BY ABDUL QAHAR DOCTOR OF PHILOSOPHY IN AGRICULTURE …prr.hec.gov.pk/jspui/bitstream/123456789/7846/1/Abdul Qahar Ph.D Thesis...NITROGEN AND SULFUR FERTILIZATION FOR ENHANCING GRAIN

NITROGEN AND SULFUR FERTILIZATION FOR ENHANCING GRAIN YIELD AND OIL QUALITY OF HIGH

OIL CORN HYBRIDS

BY

ABDUL QAHAR

A dissertation submitted to the University of Agriculture Peshawar in partial

fulfillment of the requirements for the degree of

DOCTOR OF PHILOSOPHY IN AGRICULTURE

(AGRONOMY)

DEPARTMENT OF AGRONOMY

FACULTY OF CROP PRODUCTION SCIENCES THE UNIVERSITY OF AGRICULTURE, PESHAWAR

KHYBER PAKHTUNKHWA-PAKISTAN FEBRUARY, 2015

NITROGEN AND SULFUR FERTILIZATION FOR ENHANCING GRAIN YIELD AND OIL QUALITY OF HIGH OIL

CORN HYBRIDS

BY

ABDUL QAHAR

A dissertation submitted to the University of Agriculture Peshawar in partial fulfillment of the requirements for the degree of

DOCTOR OF PHILOSOPHY IN AGRICULTURE (AGRONOMY)

Approved by:

_________________________ Chairman Supervisory Committee

Prof Dr. Bashir Ahmad

_________________________ Member (Major) Dr. Shahen Shah Assistant Professor

_________________________ Member (Minor) Dr. Dost Muhammad Assistant Professor

Deptt. of Soil & Environmental Sciences

_________________________ Chairman & Convener Board of Studies Prof. Dr. Mohammad Tariq Jan

_________________________ Dean Faculty of Crop Production Sciences Prof. Dr. Muhammad Afzal _________________________ Director Advanced Studies and Research Prof. Dr. Muhammad Jamal Khan

DEPARTMENT OF AGRONOMY

FACULTY OF CROP PRODUCTION SCIENCES THE UNIVERSITY OF AGRICULTURE, PESHAWAR

KHYBER PAKHTUNKHWA-PAKISTAN FEBRUARY, 2015

DEDICATION

To my honorable supervisor Prof. Dr. Bashir Ahmad

and to my maternal uncle Prof. Dr. Humayun Khan

Abdul Qahar

iv

NITROGEN AND SULFUR FERTILIZATION FOR ENHANCING GRAIN YIELD AND OIL QUALITY OF HIGH OIL CORN HYBRIDS

Abdul Qahar and Bashir Ahmad

Department of Agronomy, Faculty of Crop Production Sciences

The University of Agriculture, Peshawar-Pakistan

ABSTRACT

Nitrogen (N) and sulfur (S) play a crucial role in improving the grain yield and oil quality of the corn hybrids. Two years field experiments were performed to

determine the impact of N (250, 300, 350 kg ha-1) and sulfur (20, 40, 60 kg ha-1) fertilization along control (0kg N and S), using randomized complete block design with split plot arrangement, to find out the best level of both nutrients and best oil

type corn hybrid (Rafhan-3305, 2210 and 2207) for economizing maize yield, protein and oil quality, during 2013 and 2014 at the Research Farm of Agronomy department, the University of Agriculture Peshawar. Nitrogen and sulfur were

allotted to the main plot, while corn hybrids to subplot. The results showed that nitrogen and corn hybrids significantly affected tasseling, silking and plant height; however sulfur levels had a non-significant effect. With maximum level of N, tasseling and silking were delayed and plant height increased when

compared with unamended plots. R-2210 and R-2207 took more days to tasseling and silking than R-3305. R-2207 attained a maximum plant height, followed by R-2210 and R-3305, respectively. Physiological parameters (leaf

area and leaf area index) were significantly affected by nitrogen levels and corn hybrids, while sulfur levels had a non-significant effect. Leaf area and leaf area index increased with N level and R-2210 produced more leaf area and leaf area

index than R-3305 and R-2207. Among yield and yield components, 350 kg N ha-1 produced higher ear length, thousand grain weight, grain and biological yield, shelling percentage and harvest index than other levels of nitrogen.

However, sulfur levels had a non-significant effect on yield and yield components. R-2210 produced maximum yield and yield components than R-2207 and R-3305. The maximum BCR and net income were found in plots with

N and S level of 350 and 40 kg ha-1, respectively. R-2210 was observed with maximum BCR and net income. Among quality parameters, protein was significantly affected by N levels and corn hybrids; however, sulfur levels had a

non-significant effect. Maximum protein (%) was observed in plots with 350 kg N ha-1 using R-2210. Oil (%) was significantly affected by sulfur levels and corn hybrids, and high oil was found in experimental units with 40 and 60 kg S ha-1,

respectively. Post-harvest soil analysis indicated that mineral nitrogen in the soil was significantly affected by nitrogen levels and corn hybrids, and maximum mineral nitrogen was observed in plots with 350 kg N ha-1. In case of

soil analysis, sulfur and nitrogen status in the soil increased up to maximum level of sulfur and nitrogen (60 kg S and 350 kg N ha-1). Sulfur level of 60 kg ha-1 produced maximum oil content but was statistically similar to the oil content

produced with 40 kg S ha-1 and thus, it seems economical to recommend 40 kg S ha-1 for optimum oil content. Conclusively, to achieve maximum grain yield and protein, 350 kg N ha-1, while for high oil content, 40 kg S ha-1 is recommended

along with maximum level of N. Among studied hybrids, R-2210 is recommended because of high BCR, net income, grain yield, protein and oil contents.

v

ACKNOWLEDGEMENTS

I am extremely thankful to Almighty ALLAH, The most Beneficent and

Merciful, for helping me a lot in every moment of my life including this small

effort as well.

I would like to express my deepest gratitude to my honorable supervisor

Prof. Dr. Bashir Ahmad, Department of Agronomy, The University of

Agriculture, Peshawar, for giving me an opportunity to work under his

supervision. His valuable guidance provided me a sound basis for my research

work.

I am also thankful to all faculty members of the Department of

Agronomy, the University of Agriculture, Peshawar, especially Prof. Dr. Habib

Akbar, Dr. Ahmad Khan, Dr. Muhammad Arif and Dr. Shahen Shah for their

kind support and help. Moreover, I am also thankful to Dr. Dost Muhammad

and Dr. Aqib Iqbal for supporting and guiding me in my research lab work.

I am also thankful to my friends and colleagues, especially Imranuddin

and Saqib Bashir for supporting me in my field experiments.

I am indeed thankful to my family members and especially to my

maternal uncle Prof. Dr. Humayun Khan for a continuous encouragement

throughout my study.

Abdul Qahar

vi

TABLE OF CONTENTS

CHAPTER NO. TITLE PAGE NO.

ABSTRACT ................................................................................................ iv

ACKNOWLEDGEMENTS ......................................................................... v

VITAE ......................................................................................................... vii

LIST OF TABLES ...................................................................................... viii

LIST OF FIGURES .................................................................................... xi

I. INTRODUCTION ....................................................................................... 1

II. REVIEW OF LITERATURE....................................................................... 5

III. MATERIALS AND METHODS .................................................................. 24

IV. RESULTS .................................................................................................. 39

V. DISCUSSION ............................................................................................ 92

VI. SUMMARY, CONCLUSION AND RECOMMENDATIONS ..................... 106

VII. LITERATURE CITED ................................................................................ 111

APPENDICES............................................................................................ 122

vii

VITAE

The author was born on April 2nd, 1977 at a village Mayar, Tehsil and

District Mardan, Khyber Pakhtunkhwa, Pakistan. He completed his Secondary

School Examination (SSE) during 1993 from a Government High School

Mayar, Mardan and Higher Secondary School Examination (HSSE) from Nisar

Shaheed College, Risalpur during 1995. He obtained both Bachelor of Science

(Hons) and Master of Science (Hons) degree in Agriculture, with specialization

in Agronomy from University of Agriculture, Peshawar, Khyber Pakhtunkhwa

during 1999 and 2003, respectively. He has diversified experience in banking,

dairy sector and in marketing. He did MBA in marketing in 2012 from City

University of Science and Information Technology Peshawar.

(Abdul Qahar)

viii

LIST OF TABLES

TABLE NO. TITLE PAGE NO.

1 Soil physical and chemical properties at selected

experimental site ............................................................. 24

2 Days to 50% tasseling of different corn hybrids as

affected by nitrogen and sulfur ....................................... 41

3 Days to 50% silking of different corn hybrids as affected

by nitrogen and sulfur...................................................... 43

4 Plant height (cm) of different corn hybrids as affected by

nitrogen and sulfur........................................................... 45

5 Leaf area (cm2) of different corn hybrids as affected by


6 Leaf area index of different corn hybrids as affected by


7 Plant population ha-1 of different corn hybrids as

affected by nitrogen and sulfur. ...................................... 55

8 Ear length (cm) of different corn hybrids as affected by


9 Thousand grain weight (g) of different corn hybrids as

affected by nitrogen and sulfur. ...................................... 58

10 Grain yield ha-1(kg) of different corn hybrids as affected

by nitrogen and sulfur...................................................... 63

11 Shelling percentage of different corn hybrids as affected

by nitrogen and sulfur. .................................................... 65

12 Biological yield ha-1(kg) of different corn hybrids as

affected by nitrogen and sulfur ....................................... 67

13 Harvest index of different corn hybrids as affected by


14 Benefit cost ratio of different corn hybrids as affected by

nitrogen and sulfur………………………………………….

73

ix

15 Protein (%) of different corn hybrids as affected by


16 Oil content (%) of different corn hybrids as affected by

nitrogen and sulfur........................................................ 78

17 Post-harvest mineral nitrogen in soil of different corn

hybrids as affected by nitrogen and sulfur .................. 82

18 Post-harvest soil sulfur of different corn hybrids as

affected by nitrogen and sulfur. ................................... 84

19 Tissue sulfur of different corn hybrids as affected by

nitrogen and sulfur........................................................ 88

20 Total nitrogen in tissue of different corn hybrids as

affected by nitrogen and sulfur. ................................... 90

21 Combine analysis of variance of days to 50%

tasseling of different corn hybrids as affected by

nitrogen and sulfur during 2013 and 2014. ................. 122

22 Combine analysis of variance of days to 50% silking

of different corn hybrids as affected by nitrogen and

sulfur during 2013 and 2014. ....................................... 123

23 Combine analysis of variance of plant height (cm) of

different corn hybrids as affected by nitrogen and


24 Combine analysis of variance of leaf area (cm2) of



25 Combine analysis of variance of leaf area index of



26 Combine analysis of variance of plant population ha-1



27 Combine analysis of variance of ear length (cm) of



x

28 Combine analysis of variance of thousand grain

weight (g) of different corn hybrids as affected by

nitrogen and sulfur during 2013 and 2014. ............... 129

29 Combine analysis of variance of grain yield ha-1(kg)


sulfur during 2013 and 2014. ..................................... 130

30 Combine analysis of variance of shelling percentage



31 Combine analysis of variance of biological yield ha-

1(kg) of different corn hybrids as affected by nitrogen

and sulfur during 2013 and 2014. .............................. 132

32 Combine analysis of variance of harvest index of



33 Combine analysis of variance of protein (%) of



34 Combine analysis of variance of oil content (%) of



35 Combine analysis of variance of mineral nitrogen in

soil of different corn hybrids as affected by nitrogen

and sulfur during 2013 and 2014. .............................. 136

36 Combine analysis of variance of soil sulfur of



37 Combine analysis of variance of tissue sulfur of



38 Combine analysis of variance of tissue nitrogen of different corn hybrids as affected by nitrogen and


xi

LIST OF FIGURES

FIG. NO. TITLE PAGE NO.

1 Original Soxhlet (left), a) Condenser, b) Sample thimble,

c) Solvent flask, d) Siphon tube, e) Solvent vapor tube,

f) Thimble positioning mechanism, g) heater. ................ 37

2 Three step extraction procedure, including boiling,

rinsing and evaporation .................................................. 37

3 Mean monthly average temperature for the year 2013

and 2014. ........................................................................ 38

4 Mean monthly average rainfall for the year 2013 and

2014................................................................................. 38

5 Interaction between nitrogen and sulfur on days to 50%

tasseling of corn .............................................................. 42

6 Interaction between nitrogen and hybrids on days to

50% tasseling of corn. .................................................... 42

7 Interaction between nitrogen and hybrids on days to

50% silking of corn .......................................................... 44

8 Interaction between nitrogen and hybrids on plant

height of corn .................................................................. 46

9 Interaction between nitrogen and hybrids on leaf area of

corn 50

10 Interaction between nitrogen and hybrids on leaf area

index of corn .................................................................... 52

11 Interaction between nitrogen and hybrids on ear length

(cm) of corn ..................................................................... 57

12 Interaction between nitrogen and hybrids on thousand

grain weight (g) of corn ................................................... 59

13 Interaction between nitrogen and hybrids on grain yield

of corn.............................................................................. 64

14 Interaction between nitrogen, hybrids and sulfur on

grain yield of corn. ........................................................... 64

xii

15 Interaction between nitrogen and sulfur on shelling

percentage of corn. ......................................................... 66

16 Interaction between nitrogen and hybrids on shelling

percentage of corn .......................................................... 66

17 Interaction between nitrogen and hybrids on biological

yield (kg ha-1) of corn ...................................................... 68

18 Interaction between nitrogen and sulfur on harvest

index of corn .................................................................... 71

19 Interaction between nitrogen and hybrids on harvest

index of corn .................................................................... 71

20 Interaction between nitrogen and hybrids on protein (%)

of corn.............................................................................. 77

21 Interaction between nitrogen and sulfur on oil (%) of

corn .................................................................................. 79

22 Interaction between sulfur and hybrids on oil (%) of corn 79

23 Interaction between nitrogen and hybrids on post-

harvest mineral nitrogen in soil of corn .......................... 83

24 Interaction between nitrogen and sulfur on post-harvest

soil sulfur of corn ............................................................. 85

25 Interaction between nitrogen and sulfur on tissue sulfur

of corn.............................................................................. 89

26 Interaction between nitrogen and sulfur on total nitrogen

in tissue of corn. .............................................................. 89

27 Interaction between nitrogen and hybrids on total

nitrogen in tissue of corn................................................. 91

1

I. INTRODUCTION

Corn (Zea mays L.) has an important position in terms of annual grain

production (4,527 thousand tons) among cereal crops in Pakistan after wheat

(25,286 thousand tons) and rice (6,798 thousand tons). Corn can be grown

successfully in all provinces of the Pakistan, but acreage share of Punjab and

Khyber Pakhtunkhwa (KPK) is more. Corn seed has got more importance as a

commercial crop because of its large use in the agro-based industries.

Moreover, it is used as food for human consumption and as feed in the form of

grain and silage for livestock (forage) and poultry (Aurangzeb et al., 2007). Corn

grain production has been increased in Pakistan to 4,527 thousand tons in

2013-14, as compared to 4,220 thousand tons in 2012-13, with an increase of

7.3%, whereas the area under cultivation has been increased from 974 to 1083

thousand hectares (MINFA, 2014).

Corn can be grown both in spring and in autumn. With the introduction

and development of spring corn cultivars in Pakistan, an increase in spring corn

in the irrigated areas has been increased because of the active participation of

seed producing and marketing companies in Pakistan. Besides favorable soil

and climatic conditions, corn yield (kg ha-1) is below the yield produced in other

countries of the world (Farmanullah et al., 2010). The corn grain composition

varies from 11.6-20% (moisture), 1.10-2.95% (ash), 4.50–9.87% (protein), 2.17-

4.43 (fat), 2.10-26.70% (fibre) and 44.60-69.60% (carbohydrate). The nutrient

content of the grain shows significant differences except for moisture (Sule et

al., 2014). Corn seed is a good source of unsaturated oils which is good

generally and specifically for the heart patients. Corn oil has high industrial

value and significance (Ahmed et al., 1992).

2

Corn hybrids due to high yield potential have high crop growth and net

assimilation rate (Mohsin et al., 2014), and therefore require nutrients in

balance quantity, of which N is important. Hence, to achieve a maximum

potential grain yield, corn hybrids more responsive to N should be selected (De

Carvalho et al., 2012). Due to different genetic potential for N uptake and

nitrogen use efficiency, each corn hybrid needs N in different optimal quantity

(Paponov and Engels, 2003). Mostly, single cross hybrids produce higher grain

yield in response to applied inputs particularly N (Badu-Apraku et al., 2011) and

the interaction of best corn hybrid and appropriate nitrogen level will improve

grain yield according to the local conditions and environment.

Macro nutrients unavailability to the crops due to the calcareous nature

of the soil of Pakistan is very common, particularly nitrogen. Nitrogen is a major

element, associated with high photosynthetic activity, vegetative growth and a

dark green color of the leaves, because it is a part of the chlorophyll. Moreover

N is an essential component of protein, nucleic acids and N below the optimal

level, results in stunted growth. Therefore a balanced application of nitrogen

can be a factor closely related to corn grain yield (Akongwubel et al., 2012).

Corn is C4 crop, with high nutrients and water use efficiency. Nitrogen

significantly affected yield and yield components, and with an increasing

nitrogen levels, grain yield is enhanced (Khan et al., 2011, Shah et al., 2007).

Hence, it is important to optimize nitrogen application to hybrid corn for

achieving potential yield (Szulc et al., 2012).

Sulfur (S), in addition to nitrogen has an important position among

secondary macro nutrients (Platou and Jones, 1982). Corn requirement for S

and P is the same. When soil S is deficient, maximum yield of the maize cannot

3

be exploited besides the availability of all necessary nutrients (Tandon, 1989).

Sulfur is an essential nutrient necessary for plant nourishment and improving

the oil contents of seeds and quality of the crop. Combined application of S with

N is affecting the physiological and biochemical processes of crops and thus

requires intensive studies to find out their interaction for good and quality crop

production (Rasheed et al., 2004). Nitrogen application to the corn along with S,

improves not only grain yield and yield components, but also protein and oil of

the crop (Ali et al., 2013). Therefore, combined application of N and S has a

crucial role in enhancing corn grain yield and grain quality in terms of protein

and oil (Hammad et al., 2011).

The availability of sulfur in the soil significantly affects the availability of

inorganic nitrogen in the soil and hence, influences non protein nitrogen in the

tissue, leaves and reproductive parts during pollination and fertilization

(Hocking, 1987). Moreover, sulfur also affects the crop growth rate, root: shoot

ratio in corn (Clarkson, Saker and Parvez, 1989) and also the chlorophyll

contents and photosynthetic carbon dioxide fixation (Hall et al., 1972).

Deficiency of sulfur limits the availability of applied nitrogen. It has been found

that nitrogen and sulfur fertilization enhanced the concentration of both N and S

along with protein level (Walker and Booth, 1992) and the presence of sulfur in

plant tissue determine the availability of N and S for protein synthesis.

Therefore, a detailed research studies are required to find out the

nutritional behavior and the response of S in relation to N and also to know the

balanced requirements of corn for these two essential nutrients. Hence, in the

light of the above mentioned points, a two years study was designed to

investigate the effect of N and S fertilization on yield, yield components and

4

quality of high oil corn hybrids with the following objectives.

1. To find out the optimum level of nitrogen for the best yield components of

corn hybrids.

2. To find out the best level of sulfur for the economic yield of corn hybrids.

3. To investigate the interactive effect of nitrogen and sulfur on yield and

yield components of corn hybrids.

4. To select a best corn hybrid among the oil type hybrids for the best

protein and high oil contents.

5

II. REVIEW OF LITERATURE

1. Agronomic parameters

Optimum nitrogen levels could be important factor for maximizing maize

grain and biomass yield. Nitrogen (210 kg ha-1) application to the maize crop

delays tasseling (71), silking (76) and maturity (108) days (Imran et al., 2015).

Moreover it has been observed that plant height (202 cm), leaf area plant-1

(2757 cm2), leaf area index (2.16), ear length (18.0 cm), ear weight (150 g),

grains ear-1 (548), thousand grain weight (258 g) and grain yield (2673 kg ha-1)

increased with up to 210 kg N ha-1. However, biological yield (7189 kg ha-1)

increased to a maximum with 150 kg N ha-1. Inorganic nutrients (nitrogen and

sulfur) application to the maize crop significantly affects phenology, physiology,

growth and yield components of maize hybrids (Ali et al., 2013). N and S level

of 175 and 25, 175 and 35 kg ha-1 respectively, delays tasseling, silking and

results in increased leaf area (physiology), ear length, number of grains row-1

(yield components) except number of cobs plant-1 and thousand grain weight as

compared to control and other fertilizer treatments.

Maize response to plant population and nitrogen levels varies

significantly in both growing seasons (spring and summer) in terms of yield and

yield components (Asim et al., 2012). They carried out field trials to find out the

effect of nitrogen levels, plant population and sowing dates on yield

components of both spring and summer maize. Emergence m-2, days to silking

and tasseling and maturity was delayed in spring than planted in summer. The

lowest plant population (43,000 ha-1) produced plants with lowest height and

ear length when compared with higher plant population. Nitrogen increased

6

both plant height and ear height of maize, but delayed tasseling and silking.

Maximum nitrogen level of 150 kg ha-1 delayed maturity. Interaction of sowing

date and plant population, sowing date and nitrogen, plant population and

nitrogen and sowing dates, plant population and nitrogen were found significant

for leaf area index. Summer maize produced maximum grain yield than in the

spring sown crop. Nitrogen and plant population affects maize grain yield and

yield components (Dawadi and Sah, 2012). The results indicated that plant

height was increased with planting density and N levels. Phenology was not

influenced by planting densities, whereas variety and N levels had a significant

effect on days to tasseling and silking, physiological and harvest maturity. The

plant density of 66,666 plants ha-1 produced maximum value for grain yield

when compared to 55,555 plants ha-1. However, grain yield at 66,666 and at

83,333 plants ha-1 showed a non-significant response. However, increasing

plant density from 55,555 plants ha-1 to 83,333 plants ha-1 increased biological

yield, but harvest index and grain stover ratio were not significantly affected.

Likewise, 200 kg N ha-1 produced a maximum value for grain yield than 120 kg

N ha-1. The hybrids response to yield was non-significant to population levels.

Nitrogen enhances days to tasseling and silking in addition to other

macro and micro nutrients (Rafiq et al., 2010). The results showed that the

highest values for plant height, delayed tasseling, silking and grain yield were

recorded in plots with maximum level of 250 kg N ha-1 and 15 kg Zn ha-1. It was

also found that plant height and grain yield increased with increase in nutrients

and plant density levels. Nitrogen levels, enhanced days to tasseling and silking

of maize, however, zinc levels had no significant effect on days to tasseling and

silking. The nutrients levels and plant densities had a significant effect on

7

protein of maize kernel. N at maximum level enhanced protein of grain,

however maximum plant densities significantly lowered protein of grains. It was

suggested that 250 kg N ha-1 and 15 kg Zn ha-1 and a plant density of 99900

plants ha-1 showed significant results.

The availability of nitrogen and other macro-nutrients to maize on

calcareous soils is very minimal and hence results in deficiency of nutrients

(Khan et al., 2011). The results showed that all N levels, maize varieties and

interactions produced significant effects on plant growth, dry matter partitioning

and grain yield. The values for days to tasseling, silking and plant height were

highest with maximum level of nitrogen i.e. 300 kg ha-1. Maize hybrid (FH-810)

produced maximum plant height and yield components, biological yield, harvest

index and seed protein as compared to other studied hybrids. The interaction of

FH-810 and 300 kg N ha-1 produced the highest number of grain rows cob-1,

cob diameter, number of grains cob-1, 1000 grain weight, grain yield and seed

protein. The results suggested that the cultivar (FH-810) and 300 kg N ha-1

could be used for producing optimum grain yield and increasing farmer income.

Asghar et al. (2010) investigated a field study and found that with increasing

levels of nitrogen, delayed tasseling and silking, and ultimately days to crop

maturity. However, plant height was significantly increased by different levels of

NPK. The plots applied with the highest level of NPK produced plants with

maximum height in both studied varieties, which affected the yield. Hence

inadequate or high levels of NPK reduced yield of maize. The plots applied with

175-80-60 NPK level seemed to be the most optimum level to produce

maximum grain yield.

8

2. Physiological parameters

Leaf area index and crop growth rate are essential growth and yield

measuring parameters in maize (Amanullah et al., 2014). He reported that

different N-fertilizer sources, i.e. urea, calcium ammonium nitrate (CAN) and

ammonium sulfate (AS) and N rates (50, 100, 150 and 200 kg ha-1) significantly

affected mean single leaf area (MSLA), number of leaves plant-1 (NLPP), LAI

and total dry matter (TDM) of maize cultivars. The results indicated that all

experimental units treated with maximum level of N produced higher MSLA,

NLPP, LAI and TDM when compared with unamended plots. Application of

CAN and AS produced maximum MSLA, NLPP, LAI and TDM than urea. P-

3025 produced higher MSLA, NLPP, LAI and TDM than Azam and Jalal.

Ali et al. (2006) carried out field trials on six maize genotypes to study

growth and yield components. It has been observed that all cultivars

significantly differed each other with respect to leaf area plant -1, plant height at

maturity, cob length, thousand grain weight, grain yield and harvest index. The

maximum value for leaf area, thousand grain weight, grain yield and harvest

index was reported in composit-17, while R-799 was found with maximum plant

height.

Nitrogen (N) rate and its time of application affect leaf area, plant height

and biomass yield of maize, planted at low and high plant density (Amanullah et

al., 2009). At high plant density, maize resulted in significantly longer plants and

ear lengths and biological yield than at low density. Mean single leaf area and

leaf area plant-1, plant height, ear length and biological yield showed a

significant observations with N levels. Maize hybrids respond significantly with

different growth behaviors under different planting patterns and nutrient levels

9

(Rasheed et al., 2003). Crops sown on ridges produced significantly maximum

LAI, DM, CGR and a NAR than to a flat field. Sulfur level of 15 kg ha-1 along N

and P, respectively produced maximum LAI, DM, CGR and NAR than nitrogen

and phosphorous alone. Similarly, application of sulfur or magnesium or both

sulfur and magnesium to NPK produced significantly maximum values for LAI,

DM, CGR and NAR than NPK applied independently.

3. Yield and yield components

Wajid et al. (2007) carried out a field trial to study the effect of N levels

and cultivars response on yield of maize. The highest values for grain yield and

harvest index were recorded in plots with 250 kg N ha-1 than other fertilizer

treatments. The highest grain yield (8.09 t ha-1

) was produced in plots with 250

kg N ha-1

. The cultivars also showed significant response to grain yield. The

nitrogen level (250 kg ha-1) increased plant height up to 176 cm as compared to

other nitrogen levels. The 1000 grain weight was maximum (270.43g) in plot

with 250 kg N ha-1

, whereas among hybrids, maximum 1000 grain weight of

277.02 g was achieved by P-31-R-88. These findings suggested that the

cultivar P-31-R-88 and nitrogen rate of 250 kg ha-1

could be used to optimize

maize yield.

Nitrogen levels (0, 60, 120 and 180 Kg N ha-1 and corn cultivars (Kenez-

410, Korduna and Konsur) significantly affect nitrogen use efficiency (NUE),

harvest index (HI), kernels yield, 1000 kernel weight, numbers of kernels ear -1,

grain and biomass yield (Hokmalipour et al., 2010). Maximum grain yield was

obtained using Korduna with 180 kg N ha-1, however maximum NUE was found

10

with Korduna and 60 kg N ha-1. Nitrogen levels enhanced significantly increase

in number of grains row-1, number of grains ear-1 and 1000 grains weight.

Nitrogen is an important nutrient for growth and development (Iqbal et

al., 2015) and grain yield of spring maize under irrigated conditions. Results

indicate that all levels of nitrogen influence the maize grain yield and its

components. The highest grain yield (6.93 t ha-1) and biological yield (12.91 t

ha-1) was recorded in plots applied with 180 kg N ha-1 and likewise a number of

grains cob-1 (471) and 1000 grain yield (328.4g). The plant height, number of

leaves plant-1 and stem diameter were also enhanced with increased level of

applied nitrogen. Moreover, for achieving potential maize yield, nitrogen and

sulfur fertilizer, recommendations should be done one the basis of availability of

both nutrients in the soil and crop requirements (Jamal et al., 2010).

Maize grain yield and yield components of maize respond significantly to

nitrogen levels and maize hybrids. Nitrogen affects grain yield, physiological

and agronomic parameters significantly (Inamullah et al., 2011). The data

obtained from field trials showed that highest levels of N produced maximum

number of ear plant-1, ear lengths, grain ear-1, thousand grain weight, grain

yield, biomass yield and harvest index. Hybrids also responded significantly

with varied effect on ear length, number grains ear -1, thousand grain weight,

grain yield and biological yield. Pioneer 30-P-45 produced the highest harvest

index. Interaction of nitrogen and hybrids was significant on grain ear -1, grain

yield, biological yield and harvest index significantly. It has been observed that

ear plant-1, grain ear-1, thousand grain weight, grain yield, biological yield, and

harvest index increased with increase in nitrogen levels. Maize grain yield has a

11

direct relation with fertilizers levels, pesticides application and other necessary

management practices (Memon et al., 2013). It had been observed that

emergence m-2, plant height, number of grain ear-1 and grain yield produced the

highest values in deep tillage as compared to traditional and zero tillage. Total

input and output were highest in deep tillage with N, P and K at the rate of 150-

75-75 kg ha-1. Maize grain production and net income was higher in deep

tillage, followed by traditional tillage when compared with zero tillage.

Planting method and sulfur level significantly affects maize grain yield

and yield components (Manesh et al., 2013) under saline conditions. They

found that furrow planting technology had significant influence on plant height,

yield components, cations in leaves, but the number of cobs plant-1, number of

row ears-1 and number of grains ear-1 were not influenced by planting

technology. Increasing sulfur application to the soil increased all studied

characteristics.

Maize hybrids grain yield can be increased through nitrogen and plant

population management (Bozorgi et al., 2011). The study showed that grain

yield, biological yield, harvest index and yield components of maize hybrid were

significantly affected by nitrogen levels from control to 200 kg ha-1 and plant

density from 50,000 to 70,000 plants ha-1. Interaction of nitrogen levels and

plant density on grain and biological yield was also significant. Application of

poultry manure as organic source of nutrients optimizes maize grain production

and improves the structure and texture of the soil as well (Akongwubel et al.,

2012). It was noticed that poultry manure significantly affected maize growth,

biological yield, yield and yield components. Poultry manure of 20 t ha-1

12

enhanced maize plant height (cm), stem diameter (cm) and the number of

leaves plant-1 significantly; however highest thousand grain weight and grain

yield were produced in plots applied with poultry manure of 18 t ha-1 in both

growing seasons, respectively.

Maize because of its high yielding potential, a strong relation of water

and nutrient levels on crop growth and harvest index maize has been recorded

(Hammad et al., 2011). The highest values for leaf area index, number of grain

ear-1, grain yield and harvest index were reported in experimental units applied

with 250 kg N ha-1 and with eight irrigations, while maximum biological yield was

recorded in treatment with 300 kg N ha-1 with eight irrigation regimes. The

minimum thousand grain weight, biological yield and grain yield were observed

in plots with a combination of six irrigation regimes and 150 kg N ha-1.

For sustainable maize grain production, nutrient management through

agronomic practices, especially nitrogen is the prerequisite (Wasaya et al.,

2012). Tillage treatments included conventional tillage, tillage with mould board

plough and tillage with chisel plough, while nitrogen levels were applied at

different growth stages of maize. It was found that tillage methods improved

plant height, biomass yield, harvest index and shelling percentage, while

nitrogen levels had a significant influence on yield and yield components of

maize. The plots ploughed with chisel produced tallest plants, higher biomass,

harvest index and shelling percentage while mould board plough resulted to

shortest plants, lower biomass, harvest index and shelling percentage during

both the years.

13

Nitrogen application in splits to the maize crop produces the highest

biomass yield and shelling percentage. Mukhtar et al. (2011) studied the

response of maize hybrids to various nitrogen and phosphorous (NP) levels for

growth and yield component. The results indicated that different NP levels

significantly enhanced plant height, 1000 grain weight, grain number ear -1, grain

weight ear-1 and grain yield of both studied hybrids. The NP rate of 250-125 kg

ha-1 produced the highest thousand grain weight, grain number, grain weight

ear-1and grain yield, followed by 300-150 kg NP level. The highest level of NP,

i.e. 400-200 kg ha-1 affected all studied parameters with lower values, however

plant height increased. It has been suggested that especially nitrogen dose

beyond a certain level increased days to crop maturity and lowered yield.

Dibaba et al. (2013) conducted field trials to study the response of three

maize hybrids to NPK and sulfur levels. Each maize hybrid due to different

genetic potential responded differently. Pinnacle recorded higher maize yield

than QPM-1 than with Arjun. Application of NPK along with sulfur produced

significantly maximum grain yield than other fertilizer treatments. Maximum

levels of NPK produced the highest maize grain yield. Sulfur level of 30 and 40

kg ha-1 was observed with the maximum grain yield.

Moraditochaee et al. (2012) carried out a field trial on the nitrogen and

spatial management of corn hybrid in irrigated environment. They reported that

N and spacing have a significant effect on grain yield, straw yield, harvest

index, plant height, ear length, number of ear plant-1 and thousand grain weight

and the highest grain yield and yield components were recorded in

experimental units applied with 200 kg N ha-1 and 40cm spacing.

14

Spatial arrangements of different maize hybrids significantly affects yield

parameters because inter and intra plant competition has a significant role in

nutrient uptake (Azam et al., 2007). It was found that plant stand m-2, yield, yield

components and harvest index were significantly affected by hybrids and

spacing. Spacing of 15cm had significantly more emergence m-2, number of cob

m-2, lower grains cob-1

, lowest cob weight but higher biological yield. Hence it is

concluded that integration of Pioneer hybrid 3025 with plant to plant distance of

25cm produced the highest grain yield kg ha-1

.

Optimum planting density is of prime importance for exploiting the

maximum yield potential of a maize hybrid (Rehman et al., 2011). Results

indicated that the maximum value of grain yield were produced in experimental

units with 66667 plants ha-1 planting density in both years, statistically similar to

those produced in 83333 plants ha-1 planting density and the lowest grain yield

of 7.15 t ha-1 and 7.52 t ha-1 were observed in plots where planting density was

kept as 111111 plants ha-1 during both years. In case of number of ears plant-1

and grains cob-1 and 1000 grain weight, 66667 plants ha-1 produced higher

values during both years. It was suggested that planting density of 66667 plants

ha-1 produced good quality of silage and grain yield.

Proper and judicious nutrient management will not only improve organic

matter of the soil, but could also help in moisture retention (Cheema et al.,

2010). The study included combined use of poultry manure as organic source

with urea on spring maize and its effects on yield and yield components. The

combined application of urea and poultry manure had a significant impact on

yield and yield components, however highest grain yield was observed in plots

15

receiving 50% N from urea and 50% from poultry manure.

The combined application of inorganic and organic source of nutrients

produces best and environmentally safe results in terms of grain yield than sole

application (Shah et al., 2009). In a field trial, two maize cultivars and a farm

yard manure as organic source and urea as an inorganic source on a sandy

clay loam soil were taken as treatments. Both cultivars responded significantly

differently with respect to plant height, yield and yield components. Moreover

the application of both sources combined as a nutrient management strategy

improved yield significantly.

Jan and Aslam (2007) carried a field trial to study the yield potential of

maize hybrids under high nutrients management. Maize hybrids were sown at

different plant densities and at different nitrogen levels. Hybrids responded

differently to plant density and nitrogen levels. Plant density and nitrogen

application levels had increased grain yield and biomass yield. Percent ear

barrenness increased with increase in plant density, but showed an inverse

relationship with increase in nitrogen level. The study suggested that because

of the variation in the growth habit, care must be taken in the selection of

hybrids for more efficient utilization of the available resources without significant

effect on the environment.

Alam et al. (2003) carried out a field trial on yield and seed quality of

maize hybrid. The data indicated that a maximum grain yield and thousand

grain weight were found in experimental units treated with the highest level of S

(20 kg ha-1). It has been observed that increasing rates of both nitrogen and

sulfur have enhanced grain yield, shelling percentage and harvest index.

16

Moreover nitrogen also improved seed vigor, seedling shoots and root ratio;

however the effect of sulfur was non-significant on these parameters. The

interaction of both N and S with maximum levels, enhanced shoots to root ratio.

4. Economic analysis

Nutrients uptake can be increased through efficient ways to fertilize

crops and N losses can minimized (Rehman et al., 2011). It has been found that

ridge planting significantly increased grain yield, net income and benefit cost

ratio with NPK level of 200:150:150 and resulted with higher fertilizer use

efficiency, nitrogen use efficiency and N uptake efficiency. Seed quality

parameters including seed protein, oil and starch increased with each NPK

fertilizer increment.

Singh et al. (2013) reported that each maize hybrid has different genetic

potential and responded to nitrogen with varying effect. They found that Dekalb

900 M Gold had a significantly higher grain yield and yield components, i.e.

cobs plant-1, cob length (cm), grains row-1, grains cob-1, 1000 grain weight, grain

weight, shelling percentage, grain yield (6340 kg ha-1), stover yield (8550 kg

ha-1), benefit: cost ratio (2.0) and crop productivity (62.35 kg ha-1 day-1) with

maximum level of N (160 kg ha-1). However, the maximum BCR ratio (2.0) and

crop productivity (61.76 kg ha-1 day-1) with the application of 120 kg N ha-1

closely followed by 160 kg N ha-1.

Maize grain is used as staple food in almost in all parts of the country,

especially in Khyber Pakhtunkhwa. In Pakistan a mix of production technology

can be used both mechanized and traditional one (Aurangzeb et al., 2007). For

this report, 200 respondents (130 mechanized and 70 traditional) were

17

randomly selected and studied for input use and output. The field data of the

Peshawar district showed significant differences in inputs use and output at

mechanized and traditional farms. In both types of farms the benefit cost ratio of

small farm size has been usually higher than that of the larger farms and the

ratio of tenant farms was higher than that of the owner farms. However the yield

per ha-1 of the mechanized farms was 27.66% higher than that of the traditional

farms. The benefit cost ratio of mechanized farms was higher (26.60%) than

that of the traditional farms. So it has been concluded that mechanization could

bring revolutionary change both in production and profit to the farmers.

Jeet et al. (2012) reported the effect of nitrogen levels (0, 50, 100, and

150, kg ha-1) using two quality protein maize (QPM) hybrids and three levels of

sulfur (15, 30 and 45 kg ha-1). The highest plant height, leaf area index (LAI),

yield, net returns, benefit: cost ratio (B: C), lysine and tryptophan content were

recorded with maximum level of N as compared to the rest. On average

Shaktiman-4 resulted significantly with maximum plant height, maximum leaf

area index, maize grain yield, net income, BCR ratio, tryptophan content and

lysine content as compared to Shaktiman-2. In addition to this, sulfur levels

produced taller plants, highest LAI, maize grain yields, net income, BCR ratio,

tryptophan and lysine content. The Interaction effect of N × S with maximum

level produced maize grain with good quality and high BCR and net returns.

5. Quality parameters

Nitrogen is an essential nutrient which can exploit the yield potential of

the maize hybrids. Nitrogen significantly affects ear length, ear number plant-1,

seed yield and protein content (Karasu, 2012). A field trial was carried out on

18

maize cultivars and nitrogen levels to find out the best hybrid and nitrogen level

for optimum yield. It has been observed that grain yield enhanced with nitrogen

levels. The highest grain yield was resulted in plots with 300 kg N ha-1 when

compared with control plots, and had been found optimum for best grain yield

and other yield components. Moreover, the protein contents were increased

with nitrogen levels significantly. Nitrogen and sulfur have important role in

enhancing growth, grain yield and quality of maize hybrids (Rasheed et al.,

2004). It was observed that inorganic nitrogen and sulfur significantly enhanced

dry weight plant-1, grains number ear-1 and grain weight ear-1 over control

treatments. Likewise, grain yield of 8.59 tons ha-1 was observed with 150 kg

nitrogen and 30 kg sulfur ha-1, while the highest level of grain oil and protein (%)

was observed in plots applied with nitrogen @ 150 and 30, 150 and 20 kg

nitrogen and sulfur ha-1, respectively.

Nitrogen is the basic part of amino acids and proteins, whereas sulfur is

also considered as the basic unit of sulfur containing amino acids and hence

the application of both these nutrients in inorganic form significantly affects

proteins and oil contents of maize crop (Jaliya et al., 2013). A field trial,

including nitrogen and sulfur levels and maize varieties with quality proteins was

carried out. The trial was designed in RCB and arranged in a split plot with

variety (V) and nitrogen (N) in main plot and sulfur (S) levels in sub plots with

three replications. The results indicated that V, N and S fertilizers affected

maize grain protein and oil content significantly. With the increase in N levels,

protein was significantly increased, whereas oil decreased, however S affected

oil significantly, as with increase in S level, oil content was increased.

19

Maize has been a high photo thermo sensitive crop and hence it can

respond significantly to nitrogen levels (Kandil, 2013). In field experiments

maize hybrids and nitrogen levels were selected to find out the relationship of

nitrogen and hybrids on maize yield. The results indicated that N levels, hybrids

and interactions produced significant responses on maize growth and dry

matter partitioning. The maximum values for plant height, LAI, chlorophyll,

number of rows ear-1 , number of grain row-1, number of grains cob-1, thousand

grain weight, stover weight, grain weight, biological yields, harvest index and

protein content were recorded with maximum levels of nitrogen. A hybrids with

a nitrogen level of 429 kg ha-1 during the first growing season, produced ears

with maximum length and thousand grain weight, while minimum values for

thousand grain weight was produced with a nitrogen level of 214 kg ha-1. The

results concluded that hybrids with a nitrogen level of 429 kg ha-1 could be used

for producing optimum and economic grain production.

Nitrogen is one of the most essential macro nutrient affecting yield and

quality of maize (Hammad et al., 2011). In a field trial, maize hybrids with

nitrogen levels were sown to find out its effect on yield and grain quality.

Nitrogen rates significantly increased maize growth, yield and the highest

number of grains per cob, thousand grain weight, grain yield, harvest index and

nitrogen use efficiency were recorded in plots applied with 250 kg of nitrogen

ha-1, and at 300 kg N ha-1 increased biological yield up and seed protein. Hence

it is concluded that the nitrogen level of 250 kg ha-1 could enhance maize grain

yield and quality.

20

Sulfur and nitrogen are limited crop growth nutrients for yield and quality

of oil seed crop (Mumtaz et al., 2011). A field study was designed to find out the

influence of sulfur levels and nitrogen on yield and quality of canola. The results

showed that sulfur and nitrogen increased leaf area index and crop growth rate.

The maximum seed yield of 3406.21 kg ha-1 was produced in plots with 60 kg

ha-1 phosphorous and 120 kg ha-1 nitrogen followed by treatment with 40 kg ha-

1 sulfur and 120 kg ha-1 nitrogen, which gave 3388.91 kg ha-1 seed yield while

minimum seed yield of 1417.02 kg ha-1 was produced control plots, whereas the

oil content progressively increased with increase of sulfur level and with

nitrogen i.e. 42.73%. Hence it was suggested that maximum seed yield and oil

content can be produced when the crop was fertilized at the rate 40 kg ha-1

sulfur and 120 kg ha-1 nitrogen.

Seed yield and achene oil yield might be due to nitrogen management

other than genetic reasons as nitrogen has an important role in production of

unsaturated fatty acids (Ali and Sami Ullah, 2012). A field study was carried out

to study the response of N levels on seed and oil yield and quality of sunflower

hybrids. With the increase in nitrogen levels, yield and protein (%) were

increased, however oil contents responded negatively to nitrogen levels. The

Palmitic and stearic acid percentage varied from 5.27 to 6.42 % and 2.27 to

2.95%, respectively. Both studied hybrids responded differently to nitrogen

levels. However S-278 produced higher achene yield, oil content and lower

protein than Hysun-33.

Nitrogen fertilization in different maize hybrids significantly increases

chlorophyll content; yield and protein content (Vanyine et al., 2012). The

21

chlorophyll content of maize leaf increased to some level of N fertilization (120

kg N ha-1), but beyond this level (150 kg N ha-1), no significant effect was noted.

However increase in nitrogen level, enhanced grain yield and protein content of

maize hybrids.

Singh et al. (2005) investigated the response of near infrared

transmission to study changes in corn protein, oil and starch over hybrids,

planting density, N levels, and methods of N application. Generalized Linear

Model analyses of variance showed that NIT enhanced protein (%) significantly

with increasing nitrogen rate and also with the application method. The

maximum level of protein was recorded in experimental units with the highest

level of nitrogen, while minimum level was recorded in control. Oil (%) was not

significantly affected by N level and ranged from 2.2% to 4.3%; however starch

content declined when N dose was enhanced. Starch in maize ranged from

63.4% to 72.1%. The highest level of extractable starch was observed in control

(72.1%) plots, while the lowest extractable starch recorded in plots with

maximum level of nitrogen. Soil Plant Analysis Development (SPAD) readings

were enhanced significantly by nitrogen level, application method, and with

plant density. Grain yield increased from minimum to maximum in plots

receiving nitrogen @ of 0 and 202 kg ha-1 level.

6. Soil and plant analysis

Tillage techniques, fertilizer and nutrient management may help to

improve the sustainability level of maize production and more N in plant tissue

(Ahmad et al., 2009). The influence of conventional tillage and no tillage system

with nitrogen (N) levels and their application at different maize growth stages

22

were compared. Results revealed that conventional tillage not only decreased

after harvest soil nitrogen, but also enhanced grain yield and total N content in

plant tissue. Higher grain yield was produced in plots applied with maximum

level of N. Likewise N at different growth stages of maize significantly affected

after harvest soil and tissue N content. N applied at the 5th leaf stage of maize

crop lead to more accumulation of N by plant tissue. Post-harvest soil analysis

showed a significant interaction between tillage and N levels. Grain yield was

significantly affected by nitrogen levels and conventional tillage, while with 120

kg N ha-1 in no tillage produced a maximum grain yield. Conclusively

conventional tillage with 120 kg N ha-1 and split application of N produced

significant results as compared with other levels and treatments.

Nitrogen (N) and Magnesium (Mg) are secondary macro nutrients,

whose deficiency has been found in most of the soil across the world (Szule,

2010). A field trial on two maize cultivars, six levels of nitrogen and magnesium

to investigate the utilization efficiency of nitrogen from mineral fertilizer and also

on harvest index, was carried out. Results revealed that hybrid LG-2244 utilized

nitrogen to maximum level from mineral fertilizer applied and showed a

maximum N harvest index than to traditional hybrid. An increasing level of

nitrogen decreased N utilization efficiency and ultimately nitrogen harvest index;

however the application of 15 kg ha-1 magnesium by broadcast and in strip

application caused increased nitrogen efficiency from mineral fertilizer which

was observed after maize harvest soil analysis.

Among secondary nutrients, nitrogen (N) is the most important growth

variable in crop production (Blumenthal et al., 2008). Due to this reason

nitrogen fertilizer produced crops with maximum values for biomass yields, the

23

quality parameters (oil and protein) and higher concentration in plant tissue.

Nitrogen directly influences the quality of protein and hence its nutritional value.

In grains, excessive supply of nitrogen to the soil decreases the ratio of lysine

and threonine and hence diminishing the nutritional value of the protein. With

nitrogen applied to the soil generally enhances kernel quality and strength. In oil

seed crops, protein (%) are maximized with nitrogen application, however oil

(%) is lowered. Moreover, it has been observed that N fertilization response on

seed oil composition and quality is inconsistent.

Maize has high yield potential and photosynthetic efficiency, however it

requires adequate and balance quantity of nutrients for its growth and

development, especially nitrogen (Szulc et al., 2012). Leaf chlorophyll content

was found out maximum at 5th and 6th leaf stages and at the ear blooming

stage. The results indicated that chlorophyll at 5th and 6th leaf stages and grain

yield of maize was significantly affected by nitrogen and sulfur levels. Moreover

it was observed that nitrogen application at these leaf stages improved the leaf

chlorophyll, nitrogen and sulfur content, and ultimately affected the output in

terms of grain yield.

24

III. MATERIALS AND METHODS

(a). Site Description

The experiment was conducted at the Agronomy Research Farm, The

University Of Agriculture Peshawar, in the year 2013 and was repeated in 2014,

respectively. Soil analysis was done before plantation of the crop for NPK, S

and soil Physico-chemical properties of soil of the experimental site (Table 1.).

Table 1. Physico-chemical properties of soil at research site.

Soil layers (cm)

Soil property 0-15 15-30

Sand (%)

43.6

45.2 Silt (%)

45.5

33.4

Clay (%)

13.0

9.0 pH

7.36

7.63

OM content (%)

1.06

1.32 Nitrate N (mgkg-1)

7.00

5.00

Total N (%) 0.148 0.096

P (mgkg-1)

1.98

1.19

K (mgkg-1)

110

112

S (mgkg-1) 3.00

3.00

(b). Experimental Design

The experiment was designed in RCB replicated thrice with the split-plot

arrangement. Nitrogen levels (0, 250, 300 and 350 kg ha-1) and sulfur levels (0,

20, 40 and 60 kg ha-1) were kept in main plot, whereas corn hybrids i.e. R-3305

(Three way cross), R-2210 (Single cross) and R-2207 (Single cross) were

allotted to sub plots.

(c). Management of nitrogen and sulfur

Urea and ammonium sulfate was used as a source for N, while for S,

both ammonium sulfate and elemental S was applied. Nitrogen application to

the experimental units was done in splits, each at seedling, V8 and at tasseling

25

stage, while S application levels were done pre-sowing (Wajid et al., 2007),

along with basal doses of P (100 kg ha-1) and K (120kg ha-1).

(d). Agronomic Practices

The field was thoroughly ploughed for uniform seedbed preparation.

Seeding was done using 40 kg ha-1 on 7th of March during both growing

seasons. The planting was done in rows, with 75 cm apart and a plant to plant

distance of 25 cm, using a . The subplot having a size of 3.5 m x 3.75 m. Seed

treatment was done with Confidor powder (Bayer Crop Sciences) @ 10 g kg-1 of

seed before planting to control various pests during seedling establishment.

Immediately after sowing and before the emergence of the crop, the whole

experimental plot was sprayed with a pre-emergence herbicide (Premixtra) @ 2

liters ha-1 for the control of weeds. The optimum plant population was

maintained (67333 plants ha-1). Irrigation was done weekly. Chloroperifos was

sprayed @ 2 liter ha-1 and at V5 and V10 stage and Carbofuron @ 8 kg ha-1 was

also applied at V6 and knee height stage for borer control. For aphids and white

fly control, Imida (70 WP) was sprayed regularly @ 250 g ha-1.

Data was recorded on the following parameters.


1.1 Days to 50% tasseling

1.2 Days to 50% silking

1.3 Plant height (cm)


2.1 Leaf area per plant (cm2)

2.2 Leaf area index

26


3.1 Plant population at harvest ha-1

3.2 Ear length (cm)

3.3 Thousand grain weight (g)

3.4 Shelling percentage (%)

3.5 Biological yield ha-1 (kg)

3.6 Grain yield ha-1 (kg)

3.7 Harvest index (%)


4.1 Protein (%)

4.2 Oil (%)


5.1 Benefit cost ratio

6. Soil and plant analysis (N and S)

6.1 Soil analysis

6.2 Tissue analysis

Procedure for data recording

1. Agronomic Parameters

Days to 50% tasseling and silking were measured by counting the

number of days in each subplot, when 50% of the corn plants produced tassels

and silk from the date of emergence, respectively. Height of the corn plant was

recorded by measuring distance from the base to the top of the plant of

randomly selected plants in each sub plot at harvest maturity and was then

averaged to get the optimum plant height.

27

2. Physiological Parameters

Leaf area plant-1 was calculated by first multiplying average leaf length

and leaf width by a factor 0.75 (Saxena and Singh, 1965) and then this value

was multiplied with the average number of leaf plant-1 to get the leaf area plant-

1. The unit was cm2

Leaf Area = Leaf Length x Leaf width x 0.75

Leaf area of the five randomly selected corn plants was measured in m2

in each plot and then was averaged. Average leaf area plant-1, was then divided

by the area occupied by one corn plant in m2 to get the desired value of LAI.

LAI = Leaf area per plant (m2) / Ground Area (m2)


Corn plants per m2 were calculated using the formula given as under and

then from this value plants ha-1 were calculated by multiplying this value by

10000.

Number of corn plants m-1 Corn plants ha-1= ----------------------------------------------------------------- x 10,000

Number of samples x row length x row spacing

Ear length was determined by taking ten ears in each subplot at random

and the mean ear length worked out. Thousand grain weight was recorded with

the help of a sensitive electronic balance. To record data of shelling

percentage, 10 ears in each subplot were picked at random and was shelled

and weighed using the following formula.

Grains weight

Shelling (%) = ------------------------ x 100 Ear weight

28

For calculating maize grain yield, three representative rows were

harvested and threshed in each subplot and grain yield was determined by the

given formula:

Grain weight (kg) Maize grain yield (kg ha-1) = --------------------------------------------------- x 10,000

Rows length x rows spacing x rows number

Corn biological yield (kg ha-1) was measured by weight the whole dried,

harvested sample of central three rows at harvest maturity from each subplot. The

data were measured by the formula given as under.

Bundle weight (kg)

Biological yield (kg ha-1) = ---------------------------------------------------- x 10,000 Row length x row spacing x rows number

Harvest index is the ratio of grain yield and biological yield for each plot

by using the following formula. It is a unit less and expressed in percentage.

Grain yield Harvest Index (%) = ------------------------------- x 100

Biological yield


Protein (%) was determined through Bradford method for total protein

quantification (Bradford, 1976). While, for oil (%) Soxhlet apparatus method was

used for extraction of oil from dried corn grain samples from each plot using

basic principles of the Soxhlet method for extraction of crude fat (Randall,

1974).

4.1 Soxhlet procedure for extraction of fat

The representative sample was finely grounded enough to become

29

homogeneous and passed through a 1 mm sieve and weighed for 3 g using an

analytical balance. The weighing was done in a cellulose thimble with sample in

it. The Soxhlet apparatus is shown in Fig 1.

a) Drying

Drying was necessary to minimize errors in fat extraction. Drying process

reduced the chances of presence of water of soluble components in the

samples. The weighed samples were dried in the extraction thimbles at 102 °C

for 1 to 2 hours.

b) Hydrolysis

In acid hydrolysis, the selected samples were boiled with hydrochloric

acid, which had broken down bonds between fat and protein, carbohydrate and

other bounded materials.

c) Water Rinsing

Washing of the weighed samples was done with 5 aliquots of 20 ml of

deionized water. The samples were then dried to make the sample ready for

extraction procedure.

d) Solvent Extraction

The samples were thoroughly prepared and properly placed in the

Soxhlet apparatus for fat extraction and weighed for final calculation. The

samples and extraction cups were kept in the extractor. The process of

extraction of fat started when the solvent was added, followed by boiling,

rinsing, and evaporation as discussed under.

30

e) Boiling

In this step, the sample in a thimble was fully submerged in the boiling

solvent in the extraction cup. The evaporated vapors were fluxed back against a

jacket having water to cool it down and the condensed solvent flowed back

through the sample reaching back to the boiling solvent. The whole process of

oil extraction through this method is based on boiling step. The solvent used

solubilized the extract faster in hot solvent (70-90 ml) and thus increased time

utilization efficiency. A plug of cotton was put on top of the thimble to keep it in

during extraction. The required extraction times ranged from 20 to 40 min.

f) Rinsing

The sample was removed and suspended for some time over the boiling

solvent. In this step residual traces of the extractable material were removed

from the sample and were kept in the extraction cup. This step took longer (10

to 20 min) time than the boiling step to ensure proper extraction.

g) Solvent recovery

The condensed solvent continued to boil and evaporated and the

condensate was redirected out of the condenser as shown in Fig 2. The

evaporation step was completed when all solvent was flushed out from the cup,

concentrating the extract. This step required 7–10 min.

h) Post extraction

After the extraction process, the cups were removed off the Soxhlet

apparatus and placed in a drying oven at 103°C (30 minutes) to dry off any

moisture and solvent residues. Needless drying should be avoided because it

31

can oxidize fat extract and results in false readings. To calculate final weights of

the cups, extraction cups were cooled down to room temperature in

desiccators.

Calculation

The final result was calculated from the original sample weight and the

weights of the extraction cup before and after the extraction.

% Fat = (W2 – W1) / W3 × 100

Where, W1 = weight of the extraction cup,

W2 = weight of the extraction cup and extract

W3 = weight of the sample


5.1 Benefit cost ratio

For economic analysis, the benefit cost ratio was calculated by dividing

the gross income by the total expenditure (Rasheed et al., 2004) by using the

formula given below.

Gross income Benefit cost ratio = ---------------------- (PKR. ha-1)

Total Expenditure


6.1 Soil analysis

Soil samples were taken from each sub plot and were then analyzed for

mineral nitrogen in the soil using the following Kjeldhal nitrogen method.

32

Principle

Soil sample was digested in the prescribed H2SO4 concentration with the

required catalyst for raising the temperature and for enhancing organic nitrogen

to ammonium nitrogen. NH4+ was produced by steam distillation, through NaOH

to enhance the pH. The distillate was collected in a saturated H3BO3; and then

titrated with dilute H2SO4 to pH 5.0 (Bremmer and Mulvaney, 1982)

Procedure

a) Digestion

1. 1 g of air dried soil was weighed into a 100 ml tube.

2. Catalyst mixture of 5 g was added and 15 ml of concentrated sulfuric

acid and swirled with care and kept overnight.

3. The tube racks were placed in the block digester, and increased

temperature slowly to 370 0C and continued heating for about three

hours.

4. The tube racks were removed out from the block digester, and placed

carefully to cool down to room temperature.

5. About 15 ml of distilled water was added to the tubes, and brought the

volume with distilled water.

6. At least one reagent blank (no soil) was maintained.

b) Distillation

The distillation process was carried out as under.

1. 1 ml boric acid solution and 1 ml distilled water was dispensed into a 100

ml Pyrex evaporating dish.

33

2. 10 ml aliquots into a 100 ml distillation flask was pipetted out, and added

10 ml 10 N sodium hydroxide solution.

3. Immediately the flask was attached to the distillation unit with a clamp,

and distillation started and continued for three minutes.

4. After four minutes when about 35 ml of distillate was collected, the

stream supply was stopped and washed top of the condenser into the

evaporating dish with a small amount of distilled water.

5. The distillate was titrated to pH 5.0 with a standardized 0.01 N H2SO4

using the auto titrator.

6. After finishing the titration, all equipment’s were washed out.

Calculations

% Recovery: (V - B) x N x 14.01 x 100 C x D

Where

V = Volume of 0.01 N H2SO4 titrated for the sample (ml)

B = Digested blank titration volume (ml)

N = Normality of the H2SO4 solution

14.01= Atomic weight of nitrogen

C = Volume of NH4-N standard solution (ml)

D = Concentration of NH4-N standard solution (µg ml-1)

The most commonly used methods for determination of sulfur in alkaline

soils is the extraction of SO4-S with 0.15% CaCl2.2H2O (Williams and

Steinberg’s, 1959) and measurement of SO4-S concentration in the extracts by

autoturbidimetric procedure using barium chloride (Verma, 1977). 0.5434 g

potassium sulfate (K2SO4) was dissolved in distilled water and brought to 1 liter

34

volume with distilled water. This solution contained 100 ppm SO4-S (Stock

solution). A series of standard solutions from the stock solution was prepared

by diluting 5, 10, 20, 30, 40, and 50 ml stock solutions to 100 ml final volume by

adding 0.15% calcium chloride dihydrate solution. These standards contained

5, 10, 20, 30, 40, and 50 ppm SO4-S, respectively.

Procedure

a) Extraction

i. 5 g air dried soil was weighed into a 150 ml Erlenmeyer flask.

ii. 25 ml 0.15% calcium dihydrate solution was added.

iii. This stock was shaken for 30 minutes on a reciprocal shaker.

iv. A colorless extract was produced after filter the suspension through a

filter paper.

b). Measurement of SO4-S

i. Pipette out 10 ml aliquot of the extract into a 50 ml test tube.

ii. 1ml 6 M hydrochloric acid solution followed by 5 ml 70% Sorbitol solution

from a pipette was added with an enlarged jet. Finally about 1 g barium

chloride crystals were added to it.

iii. The flask was shaked vigorously for 30 seconds to dissolve barium

chloride and resulted in a homogeneous solution.

iv. A standard curve was prepared as follows;

10 ml of each standard (0–50 ppm) was pipetted out and

proceeded same for the samples.

35

A blank with 10 ml 0.15% calcium chloride dihydrate solution was

prepared and proceeded for the samples as well.

Absorbance (turbidity) reading of the blank, standards, and

samples at 470 nm wave length was observed.

A calibration curve was prepared for standards, plotted

absorbance against the respective SO4-S concentrations.

Calculation

SO4-S (ppm) = ppm SO4-S (from the calibration curve) x A / Wt

Where A is total volume of the extract

Wt is the weight of the dry soil (g)

6.2 Plant analysis

The nitrogen status in corn plant is determined by the Kjeldhal method

(Bremmer, 1996).

Sulfur analysis in plant tissue is based on the same principle of the

turbidity method of SO4- S determination, but in this case plant samples are

oven dried and then crushed and made it in powder form to pass through a 1

mm sieve. Then 0.5 g sample was taken in crucibles and burned in a furnace at

550 0C to convert it into ash and this process continued for 5 hours to attain a

temperature of 550 0C. Then this ash was dissolved in 5ml of 0.1 N HCl and

then filtered and volume was made to 100 ml with distilled water. This

supernatant was used for analysis and the rest portion discarded. Then the

same procedure was followed as in SO4-S determination in soil.

36

7. Metrological data

The mean monthly rainfall (mm) and temperature (0C) data from January to

August for the two growing seasons of 2013 and 2014 was collected and

presented in Fig 3 and 4, respectively.

8. Statistical analysis

The data collected was analyzed using analysis of variance procedure

appropriate for RCBD having arranged in split plots. The analysis was

performed by Statistix 8.1. The N and S means were evaluated by LSD test for

significant F-value (Jan et al., 2009).

37

Fig 1. Original Soxhlet (left), a) Condenser, b) Sample thimble, c) Solvent

flask, d) Siphon tube, e) Solvent vapor tube, f) Thimble positioning mechanism g) heater

Fig 2. Three step extraction procedure, including boiling, rinsing and

evaporation

38

Fig 3. Mean monthly temperature for the year 2013 and 2014

Months

Jan Feb Mar Apr May Jun Jul Aug

Tem

pera

ture

(0C

)

5

10

15

20

25

30

35

40

2013

2014

Fig 4. Mean monthly rainfall for the year 2013 and 2014

Months

Jan Feb Mar Apr May Jun Jul Aug

Ra

infa

ll (m

m)

0

50

100

150

200

250

2013

2014

39

IV. RESULTS


1.1 Days to 50% tasseling

Nitrogen levels and corn hybrids had a significant effect on days to 50%

tasseling (p < 0.01), whereas sulfur (S) levels and years had a non-significant

effect (p > 0.05) as presented in Table 2. Delayed tasseling was observed with

increase in N levels from control (51) to a maximum (59), in experimental units

with 350 kg N ha-1. Among studied hybrids, R-2210 and R-2207 took

statistically similar days to 50% tasseling (56), while earlier days to 50%

tasseling (55) was observed in R-3305.

Interactions between sulfur with nitrogen (S x N) and nitrogen with corn

hybrids (N x H) were significant (p < 0.01) as shown in Fig 5 and Fig 6,

respectively. In Fig 5 (S x N), it has been observed that nitrogen levels from 0 to

350 kg ha-1, delayed the trend of days to 50% tasseling; however, this trend

was higher for 0 and 20 kg S ha-1 as compared to 40 and 60 kg S ha-1,

respectively. Interaction between N x H showed that corn hybrids (R-2210, R-

2207) delayed days to 50% tasseling with nitrogen levels from 0 to 350 kg ha-1,

indicating a linear trend, however, corn hybrid (R-3305) showed a slightly

decreasing trend in days to 50% tasseling than R-2210 and R-2207. Mean data

for both growing seasons showed a non-significant effect on days to 50%

tasseling of corn hybrids (55).

1.2 Days to 50% silking

Days to 50% silking was significantly affected by N levels, years and

corn hybrids (p < 0.01), whereas S levels had a non-significant effect (Table 3).

It has been found that N levels, delayed days to 50% silking (65), when

40

compared with unamended plots (55). Among corn hybrids, R-2210 was found

with delayed days to 50% silking (61), followed by R-2207 (60) and R-3305

(59).

Interaction between nitrogen and corn hybrids (N x H) showed a

significant effect (p < 0.01) as presented in Fig 7, which indicated that the

delayed trend of days to 50% silking of R-2210, with N levels was more when

compared with other two hybrids i.e. R-3305 and R-2207. Moreover, all studied

hybrids showed a linear trend of increasing days to 50% silking with N levels.

Mean values for years, showed more days to 50% silking during first growing

season (61) compared to the second growing season (60).

1.3 Plant height (cm)

Nitrogen levels and corn hybrids had a significant effect (p < 0.01) on

plant height of corn hybrids as indicated in statistical analysis (Table 4);

however S levels and years had a non-significant effect. Plant height (247cm)

responded linearly with N levels in experimental units applied with 350 kg N

ha-1, compared with control (192). R-2207 produced maximum plant height of

232cm, followed by R-2210 (226) and R-3305 (221).

Nitrogen and hybrid interaction (N x H) was found significant for maize

plant height (Fig. 8), which indicated that R-3305 and R-2210 responded with a

steeper trend of increase in plant height to N levels as compared to R-2207.

41

Table 2. Days to 50% tasseling of different corn hybrids as affected by nitrogen and sulfur.

Sulfur(kg ha-1) 2013 2014 Mean

0 55 55 55

20 56 55 55

40 56 55 55

60 56 56 56

LSD(0.05) ns ns ns

Nitrogen(kg ha-1)

0 51 d 51 d 51d

250 54 c 53 c 53 c

300 57 b 57 b 57 b

350 60 a 59 a 59 a

LSD(0.05) 0.35 0.37 0.25

Hybrids

R-3305 55 b 55 b 55 b

R-2210 56 a 56 a 56 a

R-2207 56 a 56 a 56 a

LSD(0.05) 0.33 0.27 0.21

Mean 55 55

Interaction

S x N ** * **

S x H ns ns ns

N x H * ns **

S x N x H ns ns ns

Years interaction Significance level

Y x S ns

Y x N ns

Y x S x N ns

Y x H **

Y x S x H ns

Y x N x H ns

Y x S x N x H ns

Means in each category followed by different letters are significantly different among each other at P 0.05.

* = Significant at P 0.05 ** = Significant at P 0.01 ns = Non-signifiant

42

Fig 5. Interaction of nitrogen and sulfur for days to 50% tasseling of different corn hybrids

Nitorgen levels (kg ha-1

)

0 250 300 350

Days t

o 5

0%

tasselin

g

50

52

54

56

58

60

62

0 kg S ha-1

20 kg S ha-1

40 kg S ha-1

60 kg S ha-1

Fig 6. Interaction between nitrogen and hybrids for days to 50% tasseling of different corn hybrids

Nitrogen levels (kg ha-1

)

0 250 300 350

Da

ys to

50

% ta

sse

ling

0

10

20

30

40

50

60

70R-3305

R-2210

R-2207

43

Table 3. Days to 50% silking of different corn hybrids as affected by nitrogen and sulfur.


0 60 59 59

20 60 59 60

40 60 59 60

60 60 60 60

LSD(0.05) ns ns ns

Nitrogen(kg ha-1)

0 55 d 55 d 55 d

250 58 c 57 c 58 c

300 62 b 60 b 61 b

350 65 a 65 a 65 a

LSD(0.05) 0.33 0.72 0.39

Hybrids

R-3305 59 b 59 b 59 c

R-2210 60 a 60 a 61 a

R-2207 60 a 60 a 60 b

LSD(0.05) 0.22 0.32 0.19

Mean 61 a 60 b

Interaction

S x N ns ns ns

S x H ns ns ns

N x H * ** **

S x N x H ns ns ns


Y x S ns

Y x N **

Y x S x N ns

Y x H ns

Y x S x H ns

Y x N x H ns

Y x S x N x H ns

Means followed by different letters are significantly different from each other at

5% level of probability * = Significant at 5% level of probability

** = Significant at 1% level of probability ns = Non-signifiant

44

Fig 7. Interaction bewteen nitrogen and hybrids for days to 50% silking of different corn hybrids


)

0 250 300 350

Da

ys to

50

% s

ilkin

g

0

10

20

30

40

50

60

70

R-3305

R-2210

R-2207

45

Table 4. Plant height (cm) of different corn hybrids as affected by nitrogen and sulfur.


0 226 224 225

20 226 225 226

40 229 227 228

60 228 226 227

LSD(0.05) ns ns ns

Nitrogen(kg ha-1)

0 192 d 192 d 192 d

250 227 c 226 c 226 c

300 240 b 240 b 240 b

350 250 a 245 a 247 a

LSD(0.05) 3.15 3.13 2.17

Hybrids

R-3305 222 c 220 c 221 c

R-2210 227 b 226 b 226 b

R-2207 233 a 230 a 232 a

LSD(0.05) 2.10 1.89 1.40

Mean 228 227

Interaction

S x N ns * ns

S x H ns ns ns

N x H ** ** **

S x N x H ns ns ns

Year interaction Significance level

Y x S ns

Y x N *

Y x S x N ns

Y x H ns

Y x S x H ns

Y x N x H ns

Y x S x N x H ns




46

Fig 8. Interaction bewteen nitrogen and hybrids for plant height of different corn hybrids


)

0 250 300 350

Pla

nt heig

ht (c

m)

0

50

100

150

200

250

300

R-3305

R-2210

R-2207

47


2.1 Leaf area (cm2)

Statistical analysis of the data indicated that N levels, corn hybrids and

years had a significant effect on leaf area (p < 0.01), whereas S levels had a

non-significant effect (p > 0.05) presented in Table 5. The maximum values for

leaf area (6257 cm2) was recorded in plots with 350 kg N ha-1, followed by 300

(5544 cm2) and 250 kg ha-1 (4686 cm2), respectively, while minimum values for

leaf area (4424 cm2) were recorded in unamended plots (control). R-2210

produced maximum values for leaf area (5317 cm2) compared with R-2207

(5245 cm2) and R-3305 (5121 cm2).

Mean values for interaction between nitrogen and corn hybrids (N x H)

indicated a significant result on leaf area as shown in Fig 9. In control plots (N),

all hybrids responded similarly, but with increase in nitrogen level, a steeper

increase in leaf area had been observed, but more in R-2210 and R-2207 as

compared to R-3305. During both years, the maximum value for leaf area (5536

cm2) was recorded in the second growing season as compared to first growing

season (4918 cm2).

2.2 Leaf area index

Nitrogen levels, corn hybrids and years had a significant effect on leaf

area index, whereas S levels had a non-significant effect (Table 6). Mean

values for nitrogen levels showed that leaf area index (3.34) was enhanced with

350 kg N ha-1, when compared with other N levels, while minimum leaf area

index (2.36) was recorded in control plots. Among the studied corn hybrids, R-

2210 produced maximum values for leaf area index (2.84), followed by R-2207

48

(2.80) and R-3305 (2.73), respectively.

Interaction between nitrogen and corn hybrids (N x H) showed a

significant response to leaf area index as shown in Fig 10. Leaf area index of all

studied hybrids in control plots of nitrogen showed a similar trend, but as the N

levels increased, an increasing trend in leaf area index was observed, more in

R-2210 and R-2207 as compared to R-3305.

49

Table 5. Leaf area (cm2) of different corn hybrids as affected by nitrogen and sulfur.


0 4878 5515 5196

20 4892 5515 5203

40 4941 5557 5249

60 4963 5560 5262

LSD(0.05) ns ns ns

Nitrogen(kg ha-1)

0 4182 d 4666 d 4424 d

250 4497 c 4875 c 4686 c

300 5400 b 5688 b 5544 b

350 5596 a 6917 a 6257 a

LSD(0.05) 85 86 58

Hybrids

R-3305 4845 c 5397 c 5121 c

R-2210 4967 a 5667 a 5317 a

R-2207 4944 b 5546 b 5245 b

LSD(0.05) 42 48 32

Mean 4918 b 5536 a

Interaction

S x N ns ns ns

S x H ns ns ns

N x H ** ** **

S x N x H ns ns ns

Year interaction Significance level

Y x S ns

Y x N *

Y x S x N ns

Y x H *

Y x S x H ns

Y x N x H **

Y x S x N x H ns

Means in each category followed by different letters are significantly different

among each other at P 0.05. * = Significant at P 0.05

** = Significant at P 0.01 ns = Non-signifiant

50

Fig 9. Interaction between nitrogen and hybrids for leaf area of different corn hybrids


)

0 250 300 350

Le

af a

rea (

cm

2)

0

1000

2000

3000

4000

5000

6000

7000

R-3305

R-2210

R-2207

51

Table 6. Leaf area index of different corn hybrids as affected by nitrogen and sulfur.


0 2.60 2.94 2.77

20 2.61 2.94 2.78

40 2.64 2.96 2.80

60 2.65 2.97 2.81

LSD(0.05) ns ns ns

Nitrogen(kg ha-1)

0 2.23 d 2.49 d 2.36 d

250 2.40 c 2.60 c 2.50 c

300 2.88 b 3.03 b 2.96 b

350 2.98 a 3.69 a 3.34 a

LSD(0.05) 0.05 0.05 0.03

Hybrids

R-3305 2.58c 2.88 c 2.73 c

R-2210 2.65 a 3.02 a 2.84 a

R-2207 2.64 b 2.96 b 2.80 b

LSD(0.05) 0.02 0.03 0.02

Mean 2.62 b 2.95 a

Interaction

S x N ns ns ns

S x H ns ns ns

N x H ** ** **

S x N x H ns ns ns

Years interaction Significance

level

Y x S ns

Y x N *

Y x S x N ns

Y x H *

Y x S x H ns

Y x N x H **

Y x S x N x H ns




52

Fig 10. Interaction between nitrogen and hybrids fro leaf area index of different corn hybrids


)

0 250 300 350

Leaf are

a index

0

1

2

3

4

R-3305

R-2210

R-2207

53


3.1 Plant population at harvest (ha-1)

Data presented in Table 7, revealed that all factors, including main plot

(N and S) and subplot (maize hybrids) and their interactions had a non-

significant effect on plant population at harvest ha-1.

3.2 Ear length (cm)

Significant differenced were recorded among years, N levels and corn

hybrids (Table 8), except S levels. Ear length of corn increased up to 18.88 cm,

with 350 kg N ha-1, followed by 300 (16.49 cm), and 250 kg N ha-1 (14.48 cm),

respectively, however minimum values for ear length (13.23cm) were found in

unamended plots. Among studied hybrids, R-2210 produced higher ear length

(16.18 cm), when compared with R-2207 (15.78 cm) and R-3305 (15.35 cm),

respectively.

Interaction of N x H was found significant (Fig. 11), which indicated that

the response of all studied hybrids to nitrogen levels was similar with 300 kg N

ha-1, but at 350 kg N ha-1, R-2210 showed a steeper trend of increase in ear

length than other corn hybrids. During both growing seasons, higher ear length

was recorded during 2014 (16.01 cm) than the year 2013 (15.53 cm).

54

3.3 Thousand grain weight (g)

Significant differences were reported for nitrogen, maize hybrids and

years (p < 0.01), except for S levels (Table 9). Application of 350 kg N ha-1

resulted in higher thousand grain weight (341.67 g), however the lowest

response to thousand grain weight (250.97 g) was found in unamended plots.

The highest thousand grain weight was recorded using R-2210 (306.05 g),

compared to R-2207 (288.08 g) and R-3305 (281.29 g).

Nitrogen and hybrids (N x H) interaction showed that all studied corn

hybrids responded similarly to thousand grain weight in control plots, however,

as the nitrogen level increased, a steeper trend of increase in thousand grain

weight was observed as shown in Fig 12. In comparison to other hybrids (R-

3305 and R-2207), R-2210 showed a very steep linear trend of increase in

thousand grain weight. Mean values for year showed more values for thousand

grain weight during the second growing season (298.16 g) when compared with

the first growing season (285.42 g).

55

Table 7. Plant population ha-1 of different corn hybrids as affected by nitrogen and sulfur.


0

66131 66124 66127

20

66143 64490 65316

40

66161 66161 66161

60

66143 66140 66141

LSD(0.05) ns ns ns

Nitrogen(kg ha-1)

0

66127 66125 66126

250

66146 66140 66143

300

66158 64503 65330

350

66145 66147 66146

LSD(0.05) ns ns ns

Hybrids

R-3305

66148 66147 66148

R-2210

66143 64899 65521

R-2207

66142 66139 66140

LSD(0.05) ns ns ns

Mean

66144 65729 Interaction

S x N

ns ns ns

S x H

ns ns ns

N x H

ns ns ns

S x N x H ns ns ns


Y x S ns

Y x N ns

Y x S x N ns

Y x H ns

Y x S x H ns

Y x N x H ns

Y x S x N x H ns

ns = Non-signifiant.

56

Table 8. Ear length (cm) of different corn hybrids as affected by nitrogen and sulfur.


0 15.39 15.98 15.68

20 15.64 15.97 15.81

40 15.35 16.09 15.72

60 15.75 16.00 15.88

LSD(0.05) ns ns ns

Nitrogen(kg ha-1)

0 13.00 d 13.46 d 13.23 d

250 14.28 c 14.68 c 14.48 c

300 16.21 b 16.78 b 16.49 b

350 18.64 a 19.13 a 18.88 a

LSD(0.05) 0.20 0.29 0.17

Hybrids

R-3305 15.16 c 15.55 c 15.35 c

R-2210 15.85 a 16.51 a 16.18 a

R-2207 15.58 b 15.97 b 15.78 b

LSD(0.05) 0.13 0.15 0.10

Mean 15.53 b 16.01 b

Interaction

S x N * ns ns

S x H ns ns ns

N x H ** ** **

S x N x H * ns ns


Y x S *

Y x N ns

Y x S x N *

Y x H ns

Y x S x H ns

Y x N x H ns

Y x S x N x H **


5% level of probability * = Significant at 5% level of probability ** = Significant at 1% level of probability

ns = Non-signifiant

57

Fig 11. Interaction between nitrogen and hybrids for ear lenght of different corn hybrids


)

0 250 300 350

Ea

r le

ng

ht (c

m)

0

5

10

15

20

25

R-3305

R-2210

R-2207

58

Table 9. Thousand grain weight (g) of different corn hybrids as affected by nitrogen and sulfur.


0 285.08 300.83 292.96

20 282.92 296.19 289.56

40 286.89 297.56 292.22

60 286.78 298.06 292.42

LSD(0.05) Ns ns ns

Nitrogen(kg ha-1)

0 246.64 d 255.31 d 250.97 d

250 267.92 c 283.31 c 275.61 c

300 296.00 b 301.81 b 298.90 b

350 331.11 a 352.22 a 341.67 a

LSD(0.05) 3.65 4.33 2.77

Hybrids

R-3305 275.17 c 287.42 c 281.29 c

R-2210 297.75 a 314.35 a 306.05 a

R-2207 283.33 b 292.71 b 288.02 b

LSD(0.05) 3.20 2.09 1.89

Mean 285.42 b 298.16 a

Interaction

S x N ns ns ns

S x H ns ns ns

N x H ** ** **

S x N x H ns ns ns


Y x S ns

Y x N **

Y x S x N ns

Y x H *

Y x S x H ns

Y x N x H **

Y x S x N x H ns

Means in each category followed by different letters are significantly different

among each other at P 0.05. * = Significant at P 0.05

** = Significant at P 0.01 ns = Non-signifiant

59

Fig 12. Interaction between nitrogen and hybrids for thousand grain weight of different corn hybrids


)

0 250 300 350

Thousand g

rain

weig

ht (g

)

0

100

200

300

400

R-3305

R-2210

R-2207

60

3.4 Grain yield (kg ha-1)

Statistical analysis of the data revealed that N levels, corn hybrids and

years had a significant effect on grain yield; however, sulfur levels had a non-

significant effect (Table 10). It has been found that grain yield increased up to

8051 kg ha-1 with 350 N kg ha-1, when compared with 300 kg N ha-1 (7004 kg

ha-1) and 250 kg N ha-1 (5567 kg ha-1), however the lowest value of grain yield

(2970 kg ha-1) was observed in control plots. Among corn hybrids, R-2210

produced maximum value of grain yield (6063 kg ha-1), followed by R-2207

(6008 kg ha-1) and R-3305 (5622 kg ha-1), respectively.

Interactions of nitrogen and corn hybrids (N x H) and with sulfur (N x H x

S) were significant as shown in Fig 13 and 14, respectively. N x H showed that

all corn hybrids responded similarly to grain yield with 250 kg N ha-1, but at 300

and 350 kg N ha-1, all corn hybrids responded linearly to grain yield. However,

more in R-2210 as compared to R-2207 and R-3305. In case of N x H x S

interaction, all hybrids in control N, responded similarly to grain yield with all S

levels. However, with increase in N and S levels, a linear increase in grain yield

has been observed up to 300 kg N and 40 kg S ha-1 in all hybrids except R-

2210. Moreover, it is important that at 350 kg N ha-1, 40 and 60 kg S ha-1,

response to grain yield was similar in all hybrids but was more in R-2210 as

compared to R-2207 and R-3305. Year effect showed more significant values

for the second growing (5849 kg ha-1) season as compared to the first growing

season (5706 kg ha-1).

61

3.5 Shelling percentage (%)

Nitrogen levels, corn hybrids and years had a significant effect on the

shelling percentage, while S levels had a non-significant effect (Table 11).

Results indicated that shelling percentage enhanced up to 85.48% in

experimental units applied with 350 kg N ha-1, followed by 300 kg N ha-1

(82.02%) and 250 kg N ha-1(77.39%), respectively. However, the lowest value

of shelling percentage (72.11%) was recorded in unamended plots. R-2210

produced value for shelling percentage (80.70%) more when compared with R-

2207 (79.13%), and R-3305 (77.92%).

Interaction mean values for the shelling percentage showed that S x N (p

< 0.05) and N x H (p < 0.01) was significant as shown in Fig 15 and 16,

respectively. S x N showed that in control and at 250 kg N ha-1, the trend for

shelling percentage was similar at all S levels, however, with 300 kg N ha-1,

shelling percentage increased with increase in S levels. Moreover, with 350 kg

N ha-1, all S levels responded insignificantly to shelling percentage. In case of N

x H, all hybrids responded similarly to shelling percentage with all N levels up to

300 kg ha-1. However, at 350 kg N ha-1, R-2210 response to nitrogen levels for

shelling percentage was observed with a steeper trend as compared to other

studied hybrids (R-3305 and R-2207). Mean values for years showed that

during the second growing season, shelling percentage (79.88%) was more

than the first growing season (78.53%).

3.6 Biological yield (kg ha-1)

Biological yield was significantly affected by N levels and years;

however, corn hybrid had significantly varied effect, while S levels had a non-

62

significant effect (Table 12). Nitrogen levels indicated that biological yield

increased to 22905 and 22495 kg ha-1 with 350 and 300 kg N ha-1, respectively,

followed by 250 kg N ha-1 (21215 kg ha-1), while the lowest value of biological

yield was recorded in control plots (15697 kg ha-1). Among corn hybrids, R-

2210 produced maximum biological yield of 20622 kg ha-1, in comparison to R-

3305 (20617 kg ha-1) and R-2207, (20467 kg ha-1) respectively.

Interaction of nitrogen and corn hybrids (N x H) was significant for

biological yield as shown in Fig 17, which indicated that all corn hybrids showed

a non-significant trend in control plots (N), however, with increasing N levels

from 250 to 350 kg ha-1, an increasing trend in biological yield was observed.

Mean values for years showed a significant effect (p < 0.05) and more

biological yield was (19984 kg ha-1) recorded in second growing season as

compared to the first growing season (19763 kg ha-1).

63

Table 10. Grain yield (kg ha-1) of different corn hybrids as affected by nitrogen and sulfur


0 5866 5882 5874

20 5907 5873 5890

40 5846 5888 5867

60 5973 5948 5960

LSD ns ns ns

Nitrogen(kg ha-1)

0 3011 d 2928 d 2970 d

250 5560 c 5574 c 5567 c

300 7008 b 7000 b 7004 b

350 8013 a 8089 a 8051 a

LSD 132 79 75

Hybrids

R-3305 5607 c 5637 c 5622 c

R-2210 6050 a 6076 a 6063 a

R-2207 6037 b 5980 b 6008 b

LSD 81 56 49

Mean 5706 b 5849 a

Interaction

S x N ns ns ns

S x H ns ns ns

N x H ** ** **

S x N x H * ns **


Y x S *

Y x N *

Y x S x N *

Y x H ns

Y x S x H ns

Y x N x H ns

Y x S x N x H ns



ns = Non-signifiant

64

Fig 13. Interaction of nitrogen and hybrids for grain yield of different corn hybrids


)

0 250 300 350

Gra

in y

ield

(kg

ha

-1)

0

2000

4000

6000

8000

10000

R-3305

R-2210

R-2207

Fig 14. Interaction between nitrogen, hybrid and sulfur for grain yield of different corn hybrids

0 kg S ha-1

0 250 300 350

Gra

in y

ield

(kg

ha

-1)

0

2000

4000

6000

8000

10000

R-3305

R-2210

R-2207

0 250 300 350 0 250 300 350 0 250 300 350

20 kg S ha-1 60 kg S ha

-140 kg S ha

-1


)

65

Table 11. Shelling percentage of different corn hybrids as affected by nitrogen and sulfur


0 78.28 79.71 78.99

20 78.23 79.57 78.90

40 78.99 80.24 79.62

60 78.64 79.98 79.31

LSD(0.05) ns ns ns

Nitrogen(kg ha-1)

0 72.06 d 72.16 d 72.11 d

250 76.94 c 77.85 c 77.39 c

300 82.43 b 81.60 b 82.02 b

350 85.30 a 85.94 a 85.48 a

LSD(0.05) 0.94 0.64 0.55

Hybrids

R-3305 77.90 c 77.94 c 77.92 c

R-2210 80.70 a 80.70 a 80.70 a

R-2207 78.74 b 79.53 b 79.13 b

LSD(0.05) 0.72 0.33 0.39

Mean 78.53 b 79.88 a

Interaction

S x N * ns *

S x H ns ns ns

N x H ** ** **

S x N x H ns ns ns


level

Y x S ns

Y x N **

Y x S x N ns

Y x H **

Y x S x H ns

Y x N x H **

Y x S x N x H ns



ns = Non-signifiant

66

Fig 15. Interaction of nitrogen and sulfur for shelling percentage of different corn hybrids


)

0 100 200 300 400

Sh

elli

ng

pe

rce

nta

ge

70

72

74

76

78

80

82

84

86

88

0 kg S ha-1

20 kg S ha-1

40 kg S ha-1

60 kg S ha-1

Fig 16. Interaction between nitrogen and hybrids for shelling percentage of different corn hybrids


)

0 250 300 350

shelli

ng p

erc

enta

ge

0

20

40

60

80

100

R-3305

R-2210

R-2207

Table 12. Biological yield (kg ha-1) of different corn hybrids as affected by

67

nitrogen and sulfur


0 19783 20070 19927

20 19712 19905 19809

40 19519 19953 19736

60 20038 20009 20023

LSD(0.05) ns ns ns

Nitrogen(kg ha-1)

0 13582 d 13073 c 13328 c

250 20343 c 22088 b 21215 b

300 22156 b 22761 a 22458 a

350 22972 a 22015 b 22494 a

LSD(0.05) 866.69 321.57 452.71

Hybrids

R-3305 19944 a 20031 b 19988

R-2210 19422 b 20186 a 19804

R-2207 19923 a 19736 c 19829

LSD(0.05) 413.45 275.31 ns

Mean 19763 b 19984 a

Interaction

S x N ns ** ns

S x H ns ns ns

N x H ** ** **

S x N x H ns ns ns


Y x S ns

Y x N *

Y x S x N ns

Y x H *

Y x S x H ns

Y x N x H ns

Y x S x N x H ns

Means followed by different letters are significantly different from each other at 5% level of probability

* = Significant at 5% level of probability ** = Significant at 1% level of probability ns = Non-signifiant

68

Fig 17. Interaction between nitrogen and hybrid for biological yield of different corn hybrids


)

0 250 300 350

Bio

logic

al yie

ld (

kg h

a-1

)

0

5000

10000

15000

20000

25000

R-3305

R-2210

R-2207

69

3.7 Harvest index (%)

Data regarding harvest index indicated that N levels (p < 0.01) and years

(p < 0.05) had a significant effect, whereas corn hybrids had significantly varied

effect, while S levels (p > 0.05) had a non-significant effect on harvest index

(Table 13). Mean values for N levels showed that harvest index increased up to

36.23% in experimental units applied with 350 kg N ha-1, followed by 300

(30.93%) and 350 kg N ha-1 (26.37%), respectively. while the lowest values for

harvest index (21.95%) was observed in unamended plots. R-2210 and R-2207

produced maximum harvest index (29.96 and 29.07%), followed by R-3305

(27.57%).

Interaction between sulfur and nitrogen (S x N) was significant at 5% and

nitrogen with corn hybrids (N x H) was significant at 1% level of probability on

harvest index as shown in Fig 18 and 19, respectively. S x N showed that in

control N, S level response to harvest index was similar, but as nitrogen levels

increased from 250 to 350 kg ha-1, harvest index increased with each S level

from 20 to 60 kg ha-1. However, at 350 kg N ha-1, harvest index responded

similarly to all S levels. N x H indicated that all corn hybrids responded linearly

to nitrogen levels, however the response of R-2210 was steeper to harvest

index with nitrogen levels as compared to other corn hybrids. Years had a

significant effect on harvest index and more harvest index was observed

(29.11%) during the second growing season as compared to the first growing

season (18.63%).

70

Table 13. Harvest index (%) of different corn hybrids as affected by nitrogen and sulfur.


0 28.19 28.85 28.52

20 28.78 28.97 28.87

40 28.88 29.06 28.97

60 28.67 29.57 29.12

LSD(0.05) ns ns ns

Nitrogen(kg ha-1)

0 21.44 d 22.45 d 21.95 d

250 27.43 c 25.31 c 26.37 c

300 31.09 b 30.78 b 30.93 b

350 34.54 a 37.91 a 36.23 a

LSD(0.05) 0.88 0.65 0.53

Hybrids

R-3305 27.11 c 28.04 b 27.57 c

R-2210 30.07 a 29.85 a 29.96 a

R-2207 28.70 b 29.44 a 29.07 b

LSD(0.05) 0.63 0.47 0.39

Mean 28.63 b 29.11 a

Interaction

S x N ** ns *

S x H ns ns ns

N x H ** ** **

S x N x H ns ns ns


Y x S ns

Y x N *

Y x S x N *

Y x H **

Y x S x H ns

Y x N x H ns

Y x S x N x H ns



ns = Non-signifiant

71

Fig 18. Interaction between nitrogen and sulfur for hervest index of different corn hybrids


)

0 250 300 350

Harv

est

index (

%)

20

22

24

26

28

30

32

34

36

38

0 kg S ha-1

20 kg S ha-1

40 kg S ha-1

60 kg S ha-1

Fig 19. Interaction between nitrogen and hybrid for harvest index of different corn hybrids


)

0 250 300 350

Ha

rve

st in

de

x (%

)

0

10

20

30

40

50

R-3305

R-2210

R-2207

72


4.1 Benefit cost ratio (BCR)

In Table 14, the lowest values for net income and benefit cost ratio were

reported in control plots both for nitrogen and sulfur (N and S) for all studied corn

hybrids. In control S, with 350 N kg ha-1 both net income and BCR increased

linearly upto 143842/- (PKR) and 3.33, respectively with R-2210, followed by R-

2207 with net income of 143108/- (PKR) and BCR value of 3.31. However, in

control S, and with maximum level of N (350 kg ha-1), the lowest values for net

income (PKR. 131619) and BCR (3.05) was reported in plots with R-3305. Net

income and BCR values for all corn hybrids increased with 350 kg N ha-1 and 40

kg S ha-1 of R-2210 upto 153798/- (PKR) and a BCR value of 3.41, followed by R-

2207 with net income of 146390/- (PKR) and a BCR value of 3.24. Moreover, with

350 kg N ha-1 and 60 kg S ha-1, net income and BCR values for all corn hybrids

declined. Net income and BCR values were lowest in control plots i.e. 41028/-

(PKR), 1.91 for R-3305, 42393/- (PKR), 1.97 for R-2210 and 41822/- (PKR), 1.95

for R-2207, respectively.

73

Table 14. Benefit cost ratio of different corn hybrids as affected by nitrogen and sulfur.

Nitrogen (kg ha-1)

Sulfur (kg ha-1)

Corn hybrids

Grain yield

(kg ha-1)

Stover yield

(kg ha-1)

Grain value (Rs.)

Stover value (Rs.)

Gross income (Rs.)

Total expenditure

(Rs.)

Net income (Rs.)

BCR

0 0 R-3305 2548 12943 56056 6472 62528 21500 41028 1.91 0 0 R-2210 2598 13473 57156 6737 63893 21500 42393 1.97 0 0 R-2207 2576 13300 56672 6650 63322 21500 41822 1.95

250 0 R-3305 5471 22667 120358 11333 131692 35159 96533 2.75 250 0 R-2210 5503 22633 121055 11317 132372 35159 97213 2.76 250 0 R-2207 5509 20533 121187 10267 131454 35159 96295 2.74 300 0 R-3305 6567 22267 144467 11133 155600 39180 116420 2.97 300 0 R-2210 6948 23667 152856 11833 164689 39180 125509 3.20 300 0 R-2207 6848 23233 150656 11617 162273 39180 123092 3.14 350 0 R-3305 7444 22100 163772 11050 174822 43202 131619 3.05 350 0 R-2210 8002 22000 176044 11000 187044 43202 143842 3.33 350 0 R-2207 7980 21500 175560 10750 186310 43202 143108 3.31

0 20 R-3305 2958 13300 65080 6650 71730 22300 49430 2.22 0 20 R-2210 3036 13887 66799 6943 73743 22300 51443 2.31 0 20 R-2207 3004 12992 66088 6496 72584 22300 50284 2.25

250 20 R-3305 5451 21933 119918 10967 130885 36119 94766 2.62 250 20 R-2210 5603 22067 123273 11033 134307 36119 98188 2.72 250 20 R-2207 5592 20867 123031 10433 133465 36119 97346 2.70 300 20 R-3305 6500 22333 143000 11167 154167 40140 114026 2.84 300 20 R-2210 7340 23100 161480 11550 173030 40140 132890 3.31 300 20 R-2207 6977 22850 153487 11425 164912 40140 124771 3.11 350 20 R-3305 7455 21983 164010 10992 175002 44162 130839 2.96 350 20 R-2210 8150 21500 179300 10750 190050 44162 145888 3.30 350 20 R-2207 8107 22050 178354 11025 189379 44162 145217 3.29

0 40 R-3305 2990 13000 65787 6500 72287 23590 48697 2.06 0 40 R-2210 2980 13587 65567 6793 72361 23590 48771 2.07 0 40 R-2207 2984 13090 65641 6545 72186 23590 48596 2.06

250 40 R-3305 5443 22533 119735 11267 131002 37079 93923 2.53 250 40 R-2210 5573 22900 122613 11450 134063 37079 96985 2.62 250 40 R-2207 5536 20673 121788 10337 132125 37079 95046 2.56 300 40 R-3305 6667 22167 146667 11083 157750 41100 116650 2.84 300 40 R-2210 7100 22657 156200 11328 167528 41100 126428 3.08 300 40 R-2207 7067 22800 155467 11400 166867 41100 125766 3.06 350 40 R-3305 7467 22533 164267 11267 175533 45122 130411 2.89 350 40 R-2210 8510 23400 187220 11700 198920 45122 153798 3.41 350 40 R-2207 8198 22293 180365 11147 191512 45122 146390 3.24

0 60 R-3305 2896 12300 63701 6150 69851 23970 45881 1.91 0 60 R-2210 2978 12659 65505 6329 71834 23970 47864 2.00 0 60 R-2207 2952 12346 64937 6173 71110 23970 47140 1.97

250 60 R-3305 5549 22980 122082 11490 133572 38039 95533 2.51 250 60 R-2210 5820 23833 128040 11917 139957 38039 101918 2.68 250 60 R-2207 5759 21433 126702 10717 137418 38039 99380 2.61 300 60 R-3305 6533 22460 143733 11230 154963 42060 112903 2.68 300 60 R-2210 7433 22667 163533 11333 174867 42060 132806 3.16 300 60 R-2207 7367 22933 162067 11467 173533 42060 131473 3.13 350 60 R-3305 7600 23003 167200 11502 178702 46082 132619 2.88 350 60 R-2210 8400 21490 184800 10745 195545 46082 149463 3.24 350 60 R-2207 8138 22000 179025 11000 190025 46082 143943 3.12

Grain price kg-1 = PKR. 22 Stover price kg-1= PKR. 0.50

74


5.1 Protein (%)

Protein of different corn hybrids as presented in Table 15 showed that N

levels, corn hybrids and years had significant effect on protein, while the effect

of S was non-significant. The data indicated that protein (11.91) increased to

maximum with 350 kg N ha-1 when compared to other N levels i.e. 300 and 250

kg ha-1. However, the minimum values for protein were recorded in unamended

plots (9.01). R-2210 produced corn grain with maximum protein (10.44),

followed by R-2207 (10.06) and R-3305 (9.83).

Mean values of interaction between nitrogen and corn hybrid (N x H) was

significant as shown in Fig 20, which indicated that corn hybrids responded

linearly to protein with increasing N levels up to 300 kg ha-1 but at 350 kg N ha-

1, the response becomes steeper with all corn hybrids; however the trend lines

of R-2207 and R-2210 were at par with each other as compared to R-3305.

Year effect showed that during the second growing season more protein (10.42)

was recorded as compared to first growing season (9.79).

5.2 Oil (%)

Sulfur levels and corn hybrids had a significant effect on oil as shown in

Table 16, whereas N levels and years had no significant effect. Mean values for

S levels showed that oil of corn grain increased linearly in experimental units

applied with 40 kg ha-1 and 60 kg S ha-1 i.e. 6.22 and 5.94%, respectively,

followed by S level of 20 kg ha-1 (5.16), while the lowest value of oil of 4.67%

was observed in control plots for S. R-2210 was found with a maximum value

for oil (5.64), followed by R-2207 and R-3305 (5.43), respectively.

75

Mean data of interactions, including S x N, and S x H were significant as

shown in Fig 21 and Fig 22, respectively. S x N revealed that at control N, oil

content increased linearly with S levels from 0 to 60 kg ha-1, however, in control

S plots, nitrogen levels had a non-significant effect on corn grain oil. However,

the value of oil was maximum (6.29) with 60 kg S ha-1 and 300 kg N ha-1. S x H

indicated that all corn hybrids responded similarly at control S and 20 kg S ha-1,

however, at 40 and 60 kg S ha-1, oil of all studied corn hybrids increased.

However, R-2210 responded linearly with steeper (6.10-6.48) trend as

compared to R-2207 (5.87-6.08) and R-3305 (5.84-6.11), respectively.

76

Table 15. Protein (%) of different corn hybrids as affected by nitrogen and sulfur.


0 9.88 10.36 10.12

20 9.81 10.43 10.12

40 9.74 10.53 10.14

60 9.75 10.35 10.05

LSD(0.05) ns ns ns

Nitrogen(kg ha-1)

0 8.69 d 9.32 d 9.01 d

250 9.22 c 10.05 c 9.63 c

300 9.67 b 10.10 b 9.88 b

350 11.60 a 12.21 a 11.91 a

LSD(0.05) 0.18 0.15 0.12

Hybrids

R-3305 9.51 c 10.15 c 9.83 c

R-2210 10.15 a 10.73 a 10.44 a

R-2207 9.73 b 10.39 b 10.06 b

LSD(0.05) 0.12 0.11 0.08

Mean 9.79 b 10.42 a

Interaction

S x N ns ns ns

S x H ns ns ns

N x H ** ** **

S x N x H ns ns ns


Y x S ns

Y x N *

Y x S x N ns

Y x H ns

Y x S x H ns

Y x N x H ns

Y x S x N x H ns



ns = Non-signifiant

77

Fig 20. Interaction between nitrogen and hybrid for protien of different corn hybrids


)

0 250 300 350

Pro

tien (

%)

0

2

4

6

8

10

12

14

R-3305

R-2210

R-2207

78

Table 16. Oil content (%) of different corn hybrids as affected by nitrogen and sulfur.


0 4.64 d 4.70 d 4.67 d

20 5.15 c 5.18 c 5.16 c

40 5.93 b 5.95 b 5.94 b

60 6.23 a 6.22 a 6.22 a

LSD(0.05) 0.091 0.112 0.071

Nitrogen(kg ha-1)

0 5.45 5.47 5.46

250 5.54 5.55 5.54

300 5.49 5.53 5.51

350 5.47 5.50 5.48

LSD(0.05) ns ns ns

Hybrids

R-3305 5.41 c 5.45 b 5.43 b

R-2210 5.62 a 5.65 a 5.64 a

R-2207 5.44 b 5.43 c 5.43 b

LSD(0.05) 0.061 0.077 0.049

Mean 5.49 5.51

Interaction

S x N * * **

S x H ** ** **

N x H ns ns ns

S x N x H ns ns ns


level

Y x S ns

Y x N ns

Y x S x N ns

Y x H ns

Y x S x H ns

Y x N x H ns

Y x S x N x H ns



ns = Non-signifiant

79

Fig 21. Interaction between sulfur and nitrogen for oil of different corn hybrids

Sulfur levels (kg ha-1

)

0 20 40 60

Oil

(%)

4.4

4.6

4.8

5.0

5.2

5.4

5.6

5.8

6.0

6.2

6.4

0 kg N ha-1

250 kg N ha-1

300 kg N ha-1

350 kg N ha-1

Fig 22. Interaction between sulfur and hybrid for oil of different corn hybrids


)

0 20 40 60

oil (

%)

0

1

2

3

4

5

6

7

R-3305

R-2210

R-2207

80


6.1 Soil analysis

Statistical analysis of the data showed that post-harvest nitrogen (Nmin) in

the soil was significantly affected by N, corn hybrids and years (p < 0.01),

whereas S levels had non-significant effect (Table 17). Mean values for N levels

showed that Nmin enhanced (34.14 mg kg-1 of soil) with increase in N applied to

the soil (350 kg ha-1), followed by 300 (29.48 mg kg-1 of soil) and 250 kg

nitrogen ha-1 (23.97 mg kg-1 of soil), respectively. However the lowest level of N

min was reported in unamended N plots (17.10 mg kg-1 of soil). Experimental

units of R-2210 and R-2207 were reported with maximum values for Nmin (26.58

and 26.35 mg kg-1 of soil), in comparison to R-3305 (25.59 mg kg-1 of soil).

Interaction of nitrogen and corn hybrids (N x H) was significant as shown

in Fig 23, which indicated that in control N, all corn hybrids responses to Nmin

was similar. However, with each N level increment Nmin enhanced for each corn

hybrid. Mean values for the years indicated significant differences, resulting in

more Nmin in soil (27.05 mg kg-1 of soil) for the first growing season as

compared to second growing season (25.31 mg kg-1 of soil).

Data regarding sulfur (Smin) in soil showed that sulfur, nitrogen and corn

hybrids response was significant, and however years had non-significant effect.

Mean values for S levels showed that Smin values increased with each S level

increment from 20 to 60 kg S ha-1 (7.74 to 17.14 mg kg-1 of soil) in comparison

to control S (4.53 mg kg-1 of soil) (Table 18). Mean values for N levels showed

that Smin in experimental units applied with 0, 250 and 300 kg N ha-1 had a non-

significant effect with each other, but significant with N level of 350 kg ha-1(9.82

81

mg kg-1 of soil). Smin in the soil decreased with maximum level of N. Among corn

hybrids, R-3305 and R-2210 showed a statistical similar trend for Smin in the soil

in comparison to R-2207 (11.04 mg kg-1 of soil). Interaction of S x N was found

significant as shown in Fig 24. In control S, all nitrogen level responses to Smin

was similar and likewise all S levels response to Smin was statistically similar to

N levels from 0-300 kg ha-1, however beyond this level, Smin decreased with N

level (350 kg ha-1).

82

Table 17. Post-harvest nitrogen status in soil (g kg-1 of soil) of different corn hybrids as affected by nitrogen and sulfur


0 28.93 23.61 26.27

20 28.57 23.53 26.05

40 29.00 23.44 26.22

60 28.65 23.64 26.15

LSD(0.05) ns ns ns

Nitrogen(kg ha-1)

0 17.56 d 16.64 d 17.10 d

250 25.56 c 22.39 c 23.97 c

300 33.57 b 25.39 b 29.48 b

350 38.47 a 29.81 a 34.14 a

LSD(0.05) 1.79 0.50 0.91

Hybrids

R-3305 28.05 c 23.13 b 25.59 b

R-2210 29.20 a 23.50 b 26.35 a

R-2207 29.11 a 24.04 a 26.58 a

LSD(0.05) 0.65 0.32 0.36

Mean 28.79 a 23.56 b

Interaction

S x N ns ns ns

S x H ns ns ns

N x H ns ** *

S x N x H ns ns ns


Y x S ns

Y x N *

Y x S x N ns

Y x H ns

Y x S x H ns

Y x N x H ns

Y x S x N x H ns



ns = Non-signifiant

83

Fig 23. Interaction between nitrogen and hybrid for post-harvest soil nitrogen status of different corn hybrids


)

0 250 300 350

So

il n

itro

gen

(m

g k

g-1

of so

il)

0

10

20

30

40

R-3305

R-2210

R-2207

84

Table 18. Post-harvest sulfur status in soil (g kg-1 of soil) of different corn hybrids as affected by nitrogen and sulfur.


0 4.55 d 4.51 d 4.53 d

20 7.86 c 7.63 c 7.74 c

40 13.27 b 12.96 b 13.12 b

60 17.42 a 16.86 a 17.14 a

LSD(0.05) 0.76 0.75 0.52

Nitrogen(kg ha-1)

0 10.91 10.51 a 10.71 a

250 11.05 10.93 a 10.99 a

300 11.01 11.01 a 11.01 a

350 10.12 9.51 b 9.82 b

LSD(0.05) ns 0.53 0.52

Hybrids

R-3305 10.78 b 10.25 b 10.51 b

R-2210 10.50 b 10.19 b 10.34 b

R-2207 11.01 a 11.03 a 11.04 a

LSD(0.05) 0.60 0.84 0.51

Mean 10.77 10.49

Interaction

S x N ns * **

S x H ns ns ns

N x H ns ns ns

S x N x H ns ns ns


Y x S ns

Y x N ns

Y x S x N ns

Y x H ns

Y x S x H ns

Y x N x H ns

Y x S x N x H ns



ns = Non-signifiant

85

Fig 24. Interaction between sulfur and nitrogen for soil sulfur of different corn hybrids


)

0 20 40 60

Sulfur

(mg k

g-1

of soil)

2

4

6

8

10

12

14

16

18

20

0 kg N ha-1

250 kg N ha-1

300 kg N ha-1

350 kg N ha-1

86

6.2 Plant analysis

Data regarding nitrogen status in corn tissue (Ntotal) indicated that

nitrogen, sulfur and corn hybrids had a significant effect, while years had a non-

significant effect. Results indicated (Table 19) that Ntotal increased with each

increment of N level applied to the soil, and maximum values for Ntotal were

reported in experimental units applied to N level of 350 kg ha-1 (1.66%),

followed by 300 (1.30%) and 250 (1.00%) kg ha-1, respectively. However, the

minimum values of Ntotal were reported in control plots (0.71%). S levels during

two growing seasons had a non-significant effect on Ntotal; however, mean effect

for both years was significant. Maximum value for N total (1.18%) was reported in

plots with S level of 20 and 60 kg ha-1, followed by control and 40 kg S ha-1

(1.15 and 1.14%).

Among corn hybrids, experimental units with R-2210 had more Ntotal

(1.19%), when compared with R-2207 (1.15%) and R-3305 (1.14%),

respectively. Interaction between sulfur and nitrogen (S x N), nitrogen and

hybrid (N x H) were found significant as shown in Fig 26 and 27, respectively. S

x N showed in control N and 300 kg N ha-1, all S levels response to N total was

similar. However, with 250 and 350 kg N ha-1, N total showed an inconsistent

trend. N x H interaction showed that Ntotal increased with increase in N levels

linearly in case of all studied hybrids up to 250 kg ha-1 and then tapered with

300 kg and 350 kg level of nitrogen ha-1

Data regarding sulfur status (S total) showed that sulfur, nitrogen levels

and years had a significant effect (Table 20), while maize hybrids had non-

significant effect. Mean values for nitrogen levels showed that maximum values

for Stotal (0.16%) were reported in experimental plots applied with 250, 300 and

87

350 kg ha-1 of N; when compared with control (0.15%). Sulfur levels showed

that Stotal of 0.24 % was reported in plots with S level of 40 and 60 kg ha-1,

respectively, whereas minimum values (0.02 and 0.13%) for Stotal were found in

control and 20 kg S ha-1. Interaction between sulfur and nitrogen (S x N) was

significant as shown in Fig 25, which indicated that in control S, all levels of N

under study had a similar response, however, up to 40 kg S ha-1, Stotal

increased with N level of 300 kg ha-1, but after this Stotal decreased. Mean

values for years showed that Stotal for the second growing season was higher

(0.16%) as compare to the first growing season (0.15%).

88

Table 19. Nitrogen status in tissue (N total) of different corn hybrids tissue as affected by nitrogen and sulfur.


0 1.14 1.15 1.15 b

20 1.19 1.17 1.18 a

40 1.13 1.14 1.14 c

60 1.16 1.20 1.18 a

LSD(0.05) ns ns 0.034

Nitrogen(kg ha-1)

0 0.71 d 0.70 d 0.71 d

250 1.02 c 1.01 c 1.00 c

300 1.22 b 1.28 b 1.30 b

350 1.68 a 1.67 a 1.66 a

LSD(0.05) 0.054 0.045 0.034

Hybrids

R-3305 1.15 b 1.15 c 1.14 c

R-2210 1.20 a 1.20 a 1.19 a

R-2207 1.15 b 1.16 b 1.15 b

LSD(0.05) 0.017 0.021 0.014

Mean 1.16 1.17

Interaction

S x N ns ns *

S x H ns ns ns

N x H ns ns *

S x N x H ns ns ns


Y x S ns

Y x N ns

Y x S x N ns

Y x H ns

Y x S x H ns

Y x N x H ns

Y x S x N x H ns

Means followed by different letters are significantly different from each other at 5% level of probability * = Significant at 5% level of probability


89

Fig 25. Interaction between sulfur and nitrogen for nitrogen status in tissue of different corn hybrids


)

N1 N2 N3 N4

Nitro

gen (

%)

0.6

0.8

1.0

1.2

1.4

1.6

1.8

0 kg S ha-1

20 kg S ha-1

40 kg S ha-1

60 kg S ha-1

Fig 26. Interaction between nitrogen and hybrid for nitrogen status in tissue of different corn hybrids


)

0 250 300 350

Nitro

gen

(%

)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

R-3305

R-2210

R-2207

90

Table 20. Sulfur status in tissue (S total) of different corn hybrids as affected by nitrogen and sulfur


0

0.02 d 0.02 c 0.02 d

20

0.12 c 0.14 bc 0.13 c

40

0.24 a 0.24 a 0.24 a

60

0.24 a 0.24 a 0.24 a

LSD(0.05) 0.0042 0.0074 0.0042

Nitrogen(kg ha-1)

0

0.15 b 0.15 b 0.15 b

250

0.16 a 0.16 a 0.16 a

300

0.16 a 0.16 a 0.16 a

350

0.15 a 0.16 a 0.16 a

LSD(0.05) 0.0042 0.0074 0.0042

Hybrids

R-3305

0.15 0.16 0.16

R-2210

0.15 0.16 0.16

R-2207

0.16 0.16 0.16

LSD(0.05) ns ns ns

Mean

0.15 b 0.16 a Interaction

S x N

ns ** **

S x H

ns ns ns

N x H

ns ns ns

S x N x H ns ns ns


Y x S *

Y x N ns

Y x S x N *

Y x H ns

Y x S x H ns

Y x N x H ns

Y x S x N x H ns

Means followed by different letters are significantly different from each other at 5% level of probability

* = Significant at 5% level of probability ** = Significant at 1% level of probability

ns = Non-signifiant

91

Fig 27. Interaction bewteen sulfur and nitrogen for sulfur status in tissue of differnt corn hybrids


)

0 20 40 60

Sulfur

(%)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0 kg N ha-1

250 kg N ha-1

300 kg N ha-1

350 kg N ha-1

92

V. DISCUSSION


Enhanced levels of nitrogen delayed days to 50% tasseling and silking,

however plant height was increased. In addition to environmental condition,

nutrition significantly affected days to 50% tasseling and silking (Asghar et al.

2010), which are important parameters in determining physiological and harvest

maturity of maize crop (Imran et al., 2015), particularly nitrogen. Nitrogen not

only enhanced days to tasseling and silking but also increased plant height. The

most probable reason for this could be that nitrogen improved leaf chlorophyll

content and ultimately photo assimilate synthesis through the process of

photosynthesis (Szulc et al., 2012), which resulted in the high vegetative growth

of the crop. It was suggested that maximum nitrogen level delayed maturity,

and maximum days were taken to tasseling and silking (Asim et al., 2012).

Moreover, taller plants were observed with maximum level of nitrogen (Dawadi

and Sah, 2012). It has been found that nitrogen significantly affected maize

crop growth and plant height, and delayed crop physiological and harvest

maturity, and ultimately reduced grain yield (Mukhtar et al., 2011). Shah et al.

(2009) found that nitrogen in maize crop enhanced crop growth rate, which,

resulted in delayed flowering and taller plants. This might be due to the fact that

nitrogen being a major player in the process of photosynthesis responded well

in crop growth and hence significantly increased plant height (Cheema et al.,

2010). Likewise Akongwubel et al. (2012) also suggested that N in the form of

organic source significantly increased plant height and other yield parameters in

maize hybrids.

93

Sulfur being a qualitative nutrient, has no role in vegetative growth of the

plant and therefore showed no significant effect on days to tasseling, silking and

plant height. However, it has been observed that sulfur along with nitrogen

significantly affected phenology, physiology and yield components of maize (Ali

et al., 2013). Moreover, it has also been observed that S played an important

role in increasing plant height and yield components (Jeet et al., 2012).

The corn hybrids responded significantly to nitrogen levels for days to

50% tasseling, silking and an increasing trend for plant height was observed

with increase in nitrogen levels. The probable reason for this might be due to

different genetic makeup, which resulted in varied response to phenology and

physiology (Inamullah et al., 2011) and a significant interaction between

nitrogen and hybrids was found. Asim et al. (2012) found that maize hybrids

responded differently to yield and yield components with different nutrient levels

with significantly different response to tasseling and silking. In macro nutrients,

nitrogen is important, which affected yield components and plant height of

maize hybrids (Rafiq et al., 2010). Sulfur and nitrogen significantly affected days

to 50% tasseling and silking, and plant height because the combined

application both nutrients improved nutrient uptake and had a synergistic effect

(Ali et al., 2013).


Physiological parameters including leaf area (LA) and leaf area index

(LAI) are major photosynthetic machineries. Both LA and LAI increased with

each increment in nitrogen level with a varied response of corn hybrids. The

probable reason might be that nitrogen being a major part of chlorophyll,

94

increased assimilates synthesis and hence resulted in enhanced growth and

development. This increase in phtoassimilates synthesis and partitioning to

plant parts resulted in more LA and LAI (Amanullah et al., 2014). Since,

nitrogen plays very important role in the growth and development of plant parts

because N is a constituent of chlorophyll and resulted in high LA and LAI (Jeet

et al., 2012) and vigorous growth. Growth and development of maize along with

physiological parameters largely depends on nitrogen supply (Rasheed et al.,

2003) because N being a major component of chlorophyll and hence resulted

maize plant with more leaf area and leaf area index. Hammad et al. (2011) and

Kandil (2013) found that N rates affected the growth and yield of maize crop

significantly because nitrogen levels increased LA and LAI and ultimately yield

components (Mumtaz et al., 2011).

Sulfur levels had no significant effect on LA and LAI, respectively. This

might be due to the fact that sulfur has no role in vegetative growth of the

plants. Unlike these findings, S levels not only enhanced LA and LAI, but also

increased net returns and benefit cost ratio (Jeet et al., 2012 and Rasheed et

al., 2003). Maize hybrids responded significantly to nitrogen and sulfur levels for

LA and LAI, but with varied effect (Asim et al., 2012), which could be due to

different genetic potential of hybrids. Inamullah et al. (2011) found that different

varieties of maize responded differently to LA, LAI and other physiological

indicators, which could be due to the varied genetic makeup of hybrids. Kandil

(2013) observed that maize hybrids responded to nitrogen levels with varying

effect. Combined application of nitrogen and sulfur had a significant effect on

LA and LAI of each hybrid, which indicated that each hybrid responded

differently to N levels as due to genetic characteristics of maize hybrids. Similar

95

results were reported by Ali et al. (2013) and Asim et al. (2012) and found that

nitrogen and maize hybrids had significant interaction on physiological

parameters. The cultivars significantly differed from each other with regard to

leaf area plant-1 and plant height at maturity (Ali et al., 2006).


Plant population at harvest ha-1 was not significantly affected by main

plot (nitrogen and sulfur levels) and sub plot factors (maize hybrids). It might be

due to the fact that nitrogen and sulfur have no role in emergence m-2 and final

stand of the crop (Jan and Aslam, 2007. Combined application of nitrogen and

sulfur significantly enhanced ear length, which resulted in more thousand grain

weight and ultimately grain yield. This might be due to increased leaf area and

leaf area index with nitrogen, which are important variables for light interception

and photosynthesis, and resulted in more assimilates synthesis and partitioning

to plant parts (Rasheed et al., 2004). Moreover, N has a crucial role in

development of photosynthetic machinery, which resulted in vigorous growth

and development. Because of more assimilates partitioning to yield components

and ultimately, resulted in higher ear length (Karasu, 2012). Likewise Asim et al.

(2012) and Inamullah et al. (2011) findings were in line with these results.

The expected reason for no substantial influence of S on ear length is

that sulfur is not activity involved in the vegetative growth of maize crop,

however Ali et al. (2013) contrary to the present findings reported an increase in

ear length with application of S. Maize hybrids responded differently and

significantly to ear length and this might be due to the different genetic potential

of hybrids (Ali et al., 2006). Inamullah et al. (2011) and Karasu (2012) reported

96

similar results and found that different maize hybrids responded differently to

ear length. Both nitrogen and maize hybrid response to ear length was found

significant and this might be due to different genetic response of maize hybrids

to nutrients (Asim et al., 2012). Nitrogen enhanced thousand grain weight of

different maize cultivars and increased with each increment in nitrogen. This

might be due to the fact that N levels, enhanced the LA and LAI, which

increased photo assimilates synthesis and its partitioning to the yield

components and ultimately, increased thousand grain weight (Hammad et al.,

2011). Kandil (2013) and Inamullah et al. (2011) agreed with these findings.

Unlike these results, Rasheed et al. (2003) found that sulfur has a significant

role in the net assimilates synthesis and its partitioning and hence resulted in

more thousand grain weight. It has been confirmed that an increasing S

application not only enhanced plant height, biological yield, economic yield but

also number of ears plant-1, number of row ear-1 and thousand grain weight

(Manesh et al., 2013). Because of the different genetic potential of maize

hybrids, their response to thousand grain weight was varied (Inamullah et al.,

2011 and Azam et al., 2007). Maize hybrids responded significantly to thousand

grain weight, but with varied effect (Asim et al., 2012).

Nitrogen significantly affected grain yield and a linear increasing trend in

grain yield with nitrogen levels was observed. The probable reason for this

could be that maize has C4 pathway of carbon fixation and high grain yield

potential and therefore needs adequate and balance nutrition especially N. Both

N and S application improved leaf chlorophyll content and photosynthetic

efficiency and resulted in maximum grain yield (Szulc et al., 2012). Moreover,

nitrogen as major part of the chlorophyll enhanced physiological parameters

97

and ultimately photo assimilates partitioning to yield components, i.e. ear

length, thousand grain weight and hence, grain yield was increased.

Akongwubel et al. (2012) found that maximum grain yield was observed in

experimental units applied with maximum level of N, however, nitrogen level

might delay crop maturity and reduced yield (Mukhtar et al., 2011). Maize

hybrids yield can be enhanced through N application (Bozorgi et al., 2011).

Grain yield was not significantly affected by sulfur levels independently,

however in combination with N, not only improved phenology, physiology but

also increased grain yield (Ali et al., 2013). Indeed, the findings of Rasheed et

al. (2009) also confirmed that sulfur played role in enhancing maize grain yield.

Maize hybrids response to grain yield was significant with varying effect.

R-2210 produced maximum grain yield, because of maximum leaf area and leaf

area index in comparison with other studied hybrids (R-3305 and R-2207), and

hence more assimilates were partitioned to the grain. It could be also due to

different genetic characteristics of hybrids, which responded differently to

nitrogen levels (Kandil, 2013). Asim et al. (2012) reported similar results and

found that maize hybrids responded differently to grain yield with various

nitrogen levels. Significant Interactions among N x H and N x H x S were found

for corn grain yield. This might be due to the fact that different hybrids had

different responses to nitrogen fertilizers (Inamullah et al., 2011). Moreover, N

improved the uptake of S and other nutrients with varied effect of hybrids and

hence N x H x S was significant for grain yield (Jaliya et al., 2013).

Shelling percentage was significantly affected by N levels and it had

been observed that with increase in N levels, shelling percentage was

98

increased. Grain yield and yield components responded considerably to N

levels and thus shelling increased with each increment in N rate (Wasaya et al.,

2012). Shelling percentage was not significantly affected by S levels, and

probably it might be due to the fact that sulfur had a significant role in improving

the quality of the grain. However, Rasheed et al. (2004) disagreed with these

results and reported that sulfur significantly affected grain yield and shelling

percentage. Maize hybrids effect on shelling percentage was significant, but

varied. R-2210 produced maximum shelling percentage than other studied

hybrids. The most probable reason is that R-2210 produced more grain yield

and yield components and hence resulted in more shelling percentage.

Inamullah et al. (2011) suggested similar results that hybrids had significantly

different response to shelling percentage (Singh et al., 2013). N interacted

positively with hybrids and sulfur, for shelling percentage which might be due to

increase in physiological parameters which enhanced ear length, thousand

grain weight, grain yield and ultimately, shelling percentage. Moreover, each

hybrid, due to unique genetic potential, responded to nitrogen levels with varied

effect (Wasaya et al., 2012).

Nitrogen levels had a significant effect on biological yield of maize

hybrids and it has been observed that increasing N levels enhanced biological

yield up to a certain level and then become plateau. The probable reason for

this could be that nitrogen enhanced leaf area, leaf area index and ultimately

increased the biomass of the plant (Hammad et al., 2011 and Kandil, 2013).

Sulfur levels had no significant effect on biological yield, likewise other yield and

yield components. However, Rasheed et al. (2004) disagreed with these results

and reported that sulfur increased dry weight of the plant significantly. Corn

99

hybrids responded significantly to biological yield during both years which might

be due to the fact that during second growing season, rainfall was more as than

to the first growing season and hence, more moisture level resulted in higher

biomass (Szulc et al., 2012). Moreover hybrids have their own genetic potential

for biological yield and nutrients use efficiency. Wasaya et al. (2012) findings

were in line with these results and reported that the application of nitrogen

significantly increased biomass yield. Interaction of nitrogen and hybrid was

significant for biological yield, due to the reason that each hybrid has different

genetic potential for nitrogen use efficiency (Akongwubel et al., 2011). Hammad

et al. (2012) also agreed with these results and reported that the highest level of

nitrogen significantly increased biological yield. Kandil (2013) and Khan et al.

(2011) also found that biological yield responded linearly with nitrogen levels

and a significant interaction was observed between nitrogen and maize

cultivars. Inamullah et al. (2011) also reported similar results and found that

nitrogen levels increased biological yield linearly up to some extent (Dawadi

and Sah, 2012).

Harvest index was significantly affected by nitrogen levels and the

probable reason could be that nitrogen enhanced grain and biological yield of

maize hybrids and hence, more harvest index was recorded. Inamullah et al.

(2011) agreed with these findings and reported that nitrogen levels enhanced

harvest index linearly because of increase in ratio of grain and biomass yield.

Harvest index was not significantly affected by sulfur levels. Hence sulfur has

no significant role in improving grain and biological yield. Therefore no

significant effect for harvest index was observed. However Szulc et al. (2012)

disagreed and reported that sulfur significantly affected grain yield and

100

ultimately, harvest index. Maize hybrids responded significantly to harvest index

and this could be due to the fact that each hybrid has different genetic potential

and moreover each maize hybrid has significant effect on grain and biological

yield and hence affected the harvest index significantly. Azam et al. (2007)

reported similar results that maize hybrids affected harvest index significantly

and different hybrids had varied response to nitrogen levels. Interaction of

nitrogen with sulfur and hybrid was significant for harvest index which probably

be due to the fact that sulfur increased the uptake of nitrogen, and hence

enhanced grain yield more than biological yield and ultimately, more harvest

index was observed. Inamullah et al. (2011) also reported similar results and

found that each hybrid has significant interaction with nitrogen for harvest index,

which might be due to its different genetic potential.


Economic analysis with respect to benefit cost ratio (BCR) is an

important input in management decision regarding fertilizers and other

necessary agronomic operations of corn. Mechanized and modern agronomic

practices along with best nutrient management strategies not only improved

yield but also BCR ((Aurangzeb et al., 2007). It has been observed that BCR

was maximum in experimental units applied with maximum level of N (350 kg

ha-1) and S level of 40 kg ha-1. Logically, it could be due to the fact that with the

these levels of N and S resulted in higher grain yield and ultimately, more net

income and BCR was obtained (Rehman et al., 2011) than unamended plots.

R-2210 produced more grain yield and hence more net income and more BCR

values were recorded. These results were confirmed by Memon et al. (2013)

and found that maximum level of input in the form of nitrogen has resulted more

101

grain yield and hence, more benefit. Rasheed et al. (2004) recorded similar

results and reported that each nutrient whether organic or inorganic added cost

but ultimately improved the yield and hence BCR values improved.


Proteins are nitrogenous compounds and hence, nitrogen is an important

element for improving the protein content of maize grain. Nitrogen significantly

affected protein of maize grain and an increasing trend was observed in protein

with each increment in nitrogen level. It has been found that maximum protein

content in the maize grain was recorded with each increment in nitrogen (Jeet

el al., 2012) level, and moreover protein quality also improved significantly. The

possible reason might be the plenty of N that is a major portion of amino acids

and thus might resulted in maize grain with improved protein. Similar results

were reported by Karasu (2012) and found that the protein content of maize

improved linearly with nitrogen level.

Sulfur levels had a non-significant effect on protein content, however

quality might be improved as sulfur is a major part of some amino acids. These

results were confirmed by Rasheed et al. (2004) and suggested that sulfur

application with nitrogen improved protein quality of maize grain. Maize hybrids

had a significant effect on the grain protein, but varying effect. Maize grain

protein enhanced up to some extent by an increase in nitrogen levels. This is

due to the genetic potential of each hybrid for protein to nitrogen levels. These

results are similar to the findings of Jaliya et al. (2013) and suggested that

maize varieties responded significantly to protein fertilized with nitrogen.

Nitrogen fertilization of maize hybrids enhanced the leaf chlorophyll and protein

content (Vanyine et al., 2012). The possible cause might be the increase

102

amount of N bring major component of amides and ultimately, improved the

protein content of maize. Rasheed et al. (2004) and Kandil (2013) also reported

similar results and found that N significantly affected protein content and

maximum protein contents were found in plots with maximum level of nitrogen.

Nitrogen being most important nutrient for crop growth and development

produced maximum protein content of maize hybrids after fertilization with

optimum level (Blumenthal et al., 2008).

Oil content of maize grain was not significantly affected by nitrogen;

however sulfur levels and maize hybrids had significant effect on oil content.

The response of maize hybrids to nitrogen for seed oil composition and quality

is inconsistent. It has been observed that with N application improved the

protein content but oil was lowered (Blumenthal et al., 2008). However, maize

grain oil was significantly affected by sulfur levels and it has been observed that

with increase in sulfur levels, oil content of maize improved. The probable

reason for this could be that sulfur being a major part of unsaturated fatty acids

and hence, oil content of maize grain was improved (Mumtaz et al., 2011).

Maize hybrids had significantly but varied effect on oil content of maize grain,

which might be due to their genetic characteristics. Ali and Sami Ullah (2012)

disagreed with these results and found that oil contents are not due to genetic

character of seed but it is due to nutrient management. Since S role in oil of

maize grain is crucial, therefore its interaction with N and maize hybrids had

significant effect on oil content. Rasheed et al. (2004) reported similar results

that sulfur enhanced the oil content of maize hybrids. However Mumtaz et al.

(2011) reported that the addition of nitrogen in the form of inorganic fertilizer

along with sulfur enhanced the oil content of oil seed crops. Singh et al. (2005)

103

reported that sulfur along with nitrogen improved the oil content of oil seed

crops (Rehman, et al., 2011).


Post-harvest soil analysis was done for determination of mineral nitrogen

(Nmin) and sulfur (Smin) in the soil. Mineral nitrogen (mg kg-1 of soil) was

significantly affected by nitrogen levels and it has been observed that with

increase in inorganic nitrogen application to the soil, Nmin increased. This could

be due to mineral nitrogen up take by the crop and the excess of which was left

over in soil. Moreover, it might be also due to the fact that nitrogen application

improved C: N ratio in the soil, which increased mineralization and ultimately

improved the mineral nitrogen in the soil. Similar results were reported by Szule

(2010) that with increasing levels of nitrogen to crop not only enhanced crop

yield but left more mineral nitrogen in the soil. However the addition of Mg to the

soil may increase utilization of mineral nitrogen by the crop (Ahmad et al.,

2009). Sulfur levels had no significant effect on mineral nitrogen in the soil,

however maize hybrids responded significantly to mineral nitrogen in soil but

with varied effect. Jaliya et al. (2012) also reported similar results that nitrogen

application to soil did not affect the soil nitrogen content but maize hybrids had

significant effect on soil nitrogen content, which resulted in positive interaction

between nitrogen and maize hybrids. Blumenthal et al. (2008) reported similar

results that each hybrid has different response for each plant nutrient (Cheema

et al., 2010).

Soil sulfur (mg kg-1 of soil) was significantly affected by nitrogen levels

and it has been observed that with increasing nitrogen level, soil sulfur was

minimized, which might suggest that nitrogen and sulfur has a synergistic effect.

104

Moreover, sulfur is a part of nitrate reductase, which may convert the nitrate

form of nitrogen into organic form (Schulte and Kelling, 1914). Soil sulfur was

significantly affected by sulfur levels and a linear trend of increase in soil sulfur

with increasing levels of sulfur was observed. The probable reason might be

that with sulfur application, the required amount of sulfur was taken up by the

plant and the rest was left over. Maize hybrids response was varied due to their

different genetic potential for nutrients up take (Cheema et al., 2010). S

improved the nutrients up take efficiency, especially N and hence, interaction of

sulfur and nitrogen was significant on soil sulfur. These results were confirmed

by Jaliya et al. (2012) and reported that sulfur application to maize varieties

significantly affected soil sulfur.

6.2 Plant analysis

Nitrogen levels had significant on nitrogen status (Ntotal) in maize plant

tissue and there had been a linear trend of increase in Ntotal with nitrogen levels.

The probable reason for this could be that nitrogen fertilization enhanced the

availability of nitrogen in soil for plant uptake and hence resulted in more tissue

nitrogen. Jaliya et al. (2012) and Ahmad et al. (2009) confirmed these results

and reported that nitrogen application to the soil not only enhanced nitrogen

content in the tissue but also in the grain. N total in tissue was not significantly

affected by sulfur levels and probably might be due to the fact sulfur

requirements for maize as compared to nitrogen is less. Maize hybrids

significantly affected N total in tissue but with varied effect. This might be due to

the fact that each hybrid has its own genetic makeup and potential for nutrients

uptake and its utilization. Interaction of nitrogen with hybrids and sulfur was

significant on Ntotal in maize tissue. This could be because of the fact that

105

nitrogen levels enhanced Nmin in the soil for plant uptake and N being a major

component of chlorophyll, improved the phtoassimilates partitioning to all plant

parts and hence, more Ntotal in tissues were found. Camberato et al. (2012)

reported that in plant, sulfur is a component of two amino acids and occurs in

protein, in a ratio of 1 part sulfur to about 15 parts of nitrogen (1:15). Therefore,

the N: S ratio of plant tissue as well as the sulfur concentration is used to

identify sulfur deficiency. The lower the sulfur concentration and the higher the

N: S ratio, the more likely sulfur is deficient in plant. However, N: S ratio greater

than 20:1 are most likely sulfur deficient.

Nitrogen levels had significant effect on sulfur status in maize plant

(Stotal), which might be due to the fact that sulfur and nitrogen has synergistic

relationship. This is due to the fact that sulfur was applied to the soil in optimum

quantity, which met maize requirements. However, plots fertilized with all N

levels have similar effect on Stotal, when compared with control, which suggest

less requirement of maize for S. Interaction of S with N had significant effect on

Stotal and this might be due to the fact that both nitrogen and sulfur has positive

relationship. Jaliya et al. (2012) agreed with these results and reported that

sulfur application along with nitrogen had significant effect on S total in tissue and

increased with sulfur application level.

106

VI. SUMMARY, CONCLUSION AND RECOMMENDATIONS

1. Summary

The basic idea and philosophy of successful crop production is based on

balanced fertilization, which take into account all essential nutrients necessary

for successful crop growth and development. Meeting all nutrients requirements

might result in the optimization of yield potential. Maize is an exhaustive crop

which produces good grain and biomass yield at the cost of nutrients and

inputs. Nitrogen is the basic limiting growth nutrient, the cost of which has

added a significant push to costs of production. This cost of nitrogen can either

be reduced by reducing nitrogen cost or improving the effectiveness of nitrogen

application method and addition of another nutrient in combination with

nitrogen. Hence, sulfur can be the best combination with nitrogen for enhancing

not only grain yield but also quality of the grain (protein and oil). Nitrogen

availability to maize with sulfur has both cost benefits and environmental

importance as its insufficiency increases the cost of production by minimizing

yield and moreover, excessive supply of nitrogen ultimately enhances the

environmental hazards by polluting the soil.

Two years field experiments were carried out at Research Farm of the

University of Agriculture, Peshawar during Kharif 2013 and was repeated in

2014, to find out the effect of nitrogen and sulfur on grain yield and oil quality of

corn hybrids. In main plot nitrogen levels (0, 250, 300 and 350 kg ha-1) and

sulfur levels (0, 20, 40 and 60 kg ha-1) were taken, while in sub plot three maize

hybrids i.e. R-3305, R-2207 and R-2210 were planted.

107

Among agronomic parameters, days to 50% tasseling, days to 50%

silking and plant height were significantly affected by nitrogen levels, whereas

maize hybrids effect varied significantly. However the effect of sulfur was non-

significant effect. Interactions of S x N and N x H had significant effect on days

to 50% tasseling, whereas N x H had significant effect on days to 50% silking

and plant height. Results revealed that increasing nitrogen levels, delayed days

to 50% tasseling and silking, while plant height increased with varied effect.

Among studied hybrids, R-2210 and R-2207 took more days to tasseling and

silking, however R-3305 took less days to tasseling and silking. However, 2207,

produced taller plants, when compared with R3305 and R-2210.

Physiological parameters (leaf area and leaf area index) were

substantially influenced by N and maize hybrids, while sulfur levels did not

considerably affect the physiological traits. Interaction between N x H had

significant effect on both leaf area and leaf area index. Leaf area and leaf area

index increased with increase in nitrogen levels and among hybrids R-2210

significantly produced maximum leaf area and leaf area index.

Among the studied yield components ear length, thousand grain weight,

grain yield (kg ha-1), shelling percentage, biological yield (kg ha-1) and harvest

index were significantly affected by nitrogen levels and maize hybrids. However,

sulfur levels had no significant effect. While plant population at harvest ha-1 was

not significantly affected either by main plot or sub plot factors. Interaction

between N x H was remained for ear length, 1000 grain weight, grain and

biological yield, shelling (%) and harvest index, while interaction of N x S was

shelling percentage, harvest index and grain oil contents. Interaction between N

108

x S x H was significant on grain yield.

The highest value for BCR and net income was observed in experimental

plots applied with N level of 350 kg ha-1 and S level of 40 kg ha-1, when compared

with unamended plots. R-2210 produced optimum yield and best value of BCR as

compared to other studied hybrids.

Quality parameter i.e. protein (%) was significantly affected by nitrogen

levels and maize hybrids, while the effect of sulfur was non-significant. There

was a linear increasing trend of protein content of maize with increase in

nitrogen levels. Interaction of N x H was significant on protein of maize grain.

Oil content of maize grain was significantly affected by sulfur levels and likewise

protein, a linear trend of increase was observed in oil content of maize with

sulfur levels upto some extent; however maize hybrids had varied significant

effect. Interactions of S x N and S x H was significant on grain oil content.

Nitrogen levels had non-significant effect on grain oil.

Results regarding post-harvest soil analysis of the maize crop during

both growing seasons showed that nitrogen status (mg kg-1 of soil) in soil was

significantly affected by nitrogen levels and maize hybrids, while sulfur levels

had no significant effect. Interaction of N x H had significant effect. S and N

levels had significant effect on soil sulfur, however maize hybrids response

varied significantly. There had been a linear trend of increase in soil sulfur with

increase in sulfur levels. Interaction of sulfur and nitrogen (S x N) had significant

effect on soil sulfur.

109

Analysis for nitrogen status in tissue showed that sulfur and nitrogen

levels had significant effect on total nitrogen, however maize hybrids response

varied significantly. Interaction of S x N and N x H was significant on nitrogen

status in tissue and there had been a linear trend of increase with nitrogen

levels. Tissue analysis for sulfur (%) status in maize tissue showed that sulfur,

nitrogen levels and maize hybrids had a significant effect. Interaction of sulfur

and nitrogen was significant on sulfur status in maize tissue.

2. Conclusion

It is concluded that nitrogen and sulfur has significant role in increasing

grain yield and also improving the quality of the maize crop. Application of

nitrogen at the rate of 350 kg ha-1 increased ear length, thousand grain weight,

grain and biological yield (kg ha-1), shelling percentage, harvest index and also

improved the protein and nitrogen status in maize tissue and soil. Sulfur level of

60 kg ha-1 produced maximum value for oil content but was statistically similar

to the oil content produced with S level of 40 kg ha-1 and thus, it seems

economical to recommend 40 kg S ha-1 for optimum oil content. R-2210

produced the highest values for ear length, thousand grain weight, grain yield

and other yield components as compared to R-3305 and R-2207, respectively.

3. Recommendations

Combined application of N and S at the rate of 350 kg ha-1 and 40 kg

ha-1, respectively, enhanced grain yield and improved the qualitative traits of

corn hybrids. Thus it is recommended that application of N at the rate of 350 kg

ha-1 could be the best level for achieving higher grain yield and protein content.

Application of S at the rate of 40 kg ha-1 is recommended for higher grain oil

110

content. It is also added that net income and BCR values were highest with N

level of 350 kg and S level of 40 kg ha-1. Among the studied hybrids, R-2210

proved to be the best maize hybrid in terms higher grain yield, BCR, protein and

oil contents.

We believe that nitrogen and sulfur as macro-nutrients can play a

dominant role in enhancing grain yield and quality of maize crop. Hence more

research work needs to be done on the wider implications of N and S

application levels and their effect on agro-ecosystem. Furthermore, keeping in

view the importance of nitrogen and sulfur in highly nutrients intensive crops like

maize should be thoroughly studied to economize the maize yield on

sustainable basis.

111

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122

APPENDICES

Table 21. Combine analysis of variance of days to 50% tasseling of

different corn hybrids as affected by nitrogen and sulfur during 2013 and 2014.

SOV DF SS MS F-cal Significance

level

Years (Y) 1 2.53 2.53 6.63 ns

Replications 4 1.53 0.38

Sulfur (S) 3 4.29 1.43 2.57 ns

Nitrogen (N) 3 3021 1007 1811 **

S X N 9 30.95 3.44 6.18 **

Y X S 3 0.51 0.17 0.31 ns

Y X N 3 0.62 0.21 0.37 ns

Y X S X N 9 1.84 0.20 0.37 ns

Error- I 60 33.36 0.56

Hybrids (H) 2 31.36 15.68 28.76 **

S X H 6 3.31 0.55 1.01 ns

N X H 6 14.56 2.43 4.45 **

S X N X H 18 12.33 0.69 1.26 ns

Y X H 2 8.58 4.29 7.87 **

Y X S X H 6 2.75 0.46 0.84 ns

Y X N X H 6 2.06 0.34 0.63 ns

Y X S X N X H 18 6.61 0.37 0.67 ns

Error- II 128 69.78 0.55

Total 287 3248.08

123

Table 22. Combine analysis of variance of days to 50% silking of different corn hybrids as affected by nitrogen and sulfur

during 2013 and 2014.

SOV DF SS MS F-cal Significance level

Years (Y) 1 58.681 58.681 348.454 **


Sulfur (S) 3 10.528 3.509 2.578 ns

Nitrogen (N) 3 3795.694 1265.231 929.558 **

S X N 9 3.056 0.340 0.249 ns

Y X S 3 2.347 0.782 0.575 ns

Y X N 3 87.625 29.208 21.459 **

Y X S X N 9 5.792 0.644 0.473 ns

Error- I 60 81.667 1.361

Hybrids (H) 2 58.340 29.170 64.623 **

S X H 6 1.076 0.179 0.397 ns

N X H 6 17.076 2.846 6.305 **

S X N X H 18 7.174 0.399 0.883 ns

Y X H 2 1.382 0.691 1.531 ns

Y X S X H 6 2.924 0.487 1.079 ns

Y X N X H 6 5.146 0.858 1.900 ns

Y X S X N X H 18 8.438 0.469 1.038 ns

Error- II 128 57.778 0.451

Total 287 4209.278

124

Table 23. Combine analysis of variance of plant height (cm) of different corn hybrids as affected by nitrogen and sulfur during 2013

and 2014.


level

Years (Y) 1 200 200 6.21 ns


Sulfur (S) 3 340.36 113.45 2.67 ns

Nitrogen (N) 3 129800 43266 1017.61 **

S X N 9 654.56 72.73 1.71 ns

Y X S 3 18.36 6.12 0.14 ns

Y X N 3 371.53 123.84 2.91 *

Y X S X N 9 653.00 72.56 1.71 ns

Error- I 60 2551.08 42.52

Hybrids (H) 2 5240.40 2620.20 109.03 **

S X H 6 209.41 34.90 1.45 ns

N X H 6 2086.33 347.72 14.47 **

S X N X H 18 341.42 18.97 0.79 ns

Y X H 2 70.15 35.07 1.46 ns

Y X S X H 6 81.33 13.55 0.56 ns

Y X N X H 6 187.24 31.21 1.30 ns

Y X S X N X H 18 331.06 18.39 0.77 ns

Error- II 128 3076.00 24.03

Total 287 146342.00

125

Table 24. Combine analysis of variance of leaf area (cm2) of different corn hybrids as affected by nitrogen and sulfur during 2013

and 2014.


Years (Y) 1 27493584 27493584 312.20 **

Replications 4 352259 88065

Sulfur (S) 3 228154 76051 2.43 ns

Nitrogen (N) 3 15107912

6

50359709 1610.0

1

**

S X N 9 127203 14134 0.45 ns

Y X S 3 15096 5032 0.16 ns

Y X N 3 12221682 4073894 130.24 **

Y X S X N 9 53182 5909 0.19 ns

Error- I 60 1876748 31279

Hybrids (H) 2 1882794 941397 74.88 **

S X H 6 14595 2433 0.19 ns

N X H 6 1040004 173334 13.79 **

S X N X H 18 74930 4163 0.33 ns

Y X H 2 273614 136807 10.88 **

Y X S X H 6 17090 2848 0.23 ns

Y X N X H 6 254178 42363 3.37 **

Y X S X N X H 18 56905 3161 0.25 ns

Error- II 128 1609330 12573

Total 287 19867047

4

126

Table 25. Combine analysis of variance of leaf area index of different corn hybrids as affected by nitrogen and sulfur during 2013

and 2014.


level

Years (Y) 1 7.82 7.82 312.20 **


Sulfur (S) 3 0.06 0.02 2.43 ns

Nitrogen (N) 3 42.97 14.32 1610.01 **

S X N 9 0.04 0.00 0.45 ns

Y X S 3 0.00 0.00 0.16 ns

Y X N 3 3.48 1.16 130.24 **

Y X S X N 9 0.02 0.00 0.19 ns

Error- I 60 0.53 0.01

Hybrids (H) 2 0.54 0.27 74.88 **

S X H 6 0.00 0.00 0.19 ns

N X H 6 0.30 0.05 13.79 **

S X N X H 18 0.02 0.00 0.33 ns

Y X H 2 0.08 0.04 10.88 **

Y X S X H 6 0.00 0.00 0.23 ns

Y X N X H 6 0.07 0.01 3.37 **

Y X S X N X H 18 0.02 0.00 0.25 ns

Error- II 128 0.46 0.00

Total 287 56.51

127

Table 26. Combine analysis of variance for plant population at harvest ha-1 of different corn hybrids as affected by nitrogen and

sulfur during 2013 and 2014.


level

Years (Y) 1 12431344 12431344 1.00 ns

Replications 4 49900069 12475017

Sulfur (S) 3 36977441 12325813 1.01 ns

Nitrogen (N) 3 35285697 11761899 0.96 ns

S X N 9 110074949 12230549 1.00 ns

Y X S 3 36756165 12252055 1.01 ns

Y X N 3 36888462 12296154 1.01 ns

Y X S X N 9 111204034 12356003 1.01 ns

Error- I 60 731450902 12190848

Hybrids (H) 2 24859045 12429522 1.01 ns

S X H 6 74938754 12489792 1.01 ns

N X H 6 73325111 12220851 0.99 ns

S X N X H 18 225654021 12536334 1.02 ns

Y X H 2 24682303 12341151 1.00 ns

Y X S X H 6 74088851 12348141 1.00 ns

Y X N X H 6 73955992 12325998 1.00 ns

Y X S X N X H 18 221828341 12323796 1.00 ns

Error- II 128 1578598827 12332803

Total 287 3532900317.97

128

Table 27. Combine analysis of variance of ear length (cm) of different corn hybrids as affected by nitrogen and sulfur during 2013

and 2014.


Years (Y) 1 16.53 16.53 122.08 **


Sulfur (S) 3 1.61 0.54 1.97 ns

Nitrogen (N) 3 1319.69 439.90 1620.09 **

S X N 9 4.47 0.50 1.83 ns

Y X S 3 2.80 0.93 3.44 *

Y X N 3 0.26 0.09 0.32 ns

Y X S X N 9 1.13 0.13 0.46 ns

Error- I 60 16.29 0.27

Hybrids (H) 2 32.72 16.36 133.66 **

S X H 6 0.98 0.16 1.34 ns

N X H 6 16.43 2.74 22.38 **

S X N X H 18 3.49 0.19 1.58 ns

Y X H 2 1.06 0.53 4.35 *

Y X S X H 6 1.24 0.21 1.69 ns

Y X N X H 6 1.45 0.24 1.98 ns

Y X S X N X H 18 3.87 0.21 1.76 *

Error- II 128 15.67 0.12

Total 287 1440.25

129

Table 28. Combine analysis of variance of thousand grain weight (g) of different corn hybrids as affected by nitrogen and sulfur



level

Years (Y) 1 11691.75 11691.75 68.69 **


Sulfur (S) 3 499.48 166.49 2.41 ns

Nitrogen (N) 3 321560.70 107186.90 1550.69 **

S X N 9 474.73 52.75 0.76 ns

Y X S 3 284.15 94.72 1.37 ns

Y X N 3 2551.87 850.62 12.31 **

Y X S X N 9 257.17 28.57 0.41 ns

Error- I 60 4147.33 69.12

Hybrids (H) 2 31471.55 15735.77 357.98 **

S X H 6 401.76 66.96 1.52 ns

N X H 6 12068.12 2011.35 45.76 **

S X N X H 18 622.24 34.57 0.79 ns

Y X H 2 635.88 317.94 7.23 **

Y X S X H 6 515.26 85.88 1.95 ns

Y X N X H 6 2235.12 372.52 8.47 **

Y X S X N X H 18 481.63 26.76 0.61 ns

Error- II 128 5626.44 43.96

Total 287 396206.08

130

Table 29. Combine analysis of variance of grain yield (kg ha-1) of different corn hybrids as affected by nitrogen and sulfur



level

Years (Y) 1 8.16 8.16 0.00 **

Replications 4 216350.42 54087.60

Sulfur (S) 3 391616.51 130538.84 2.55 ns

Nitrogen (N) 3 1047103789.39 349034596.46 6816.44 **

S X N 9 558882.96 62098.11 1.21 ns

Y X S 3 69387.49 23129.16 0.45 ns

Y X N 3 233075.75 77691.92 1.52 ns

Y X S X N 9 360802.66 40089.18 0.78 ns

Error- I 60 3072291.43 51204.86

Hybrids (H) 2 11074402.61 5537201.30 186.11 **

S X H 6 365482.85 60913.81 2.05 ns

N X H 6 7627912.43 1271318.74 42.73 **

S X N X H 18 1314794.88 73044.16 2.46 **

Y X H 2 114112.34 57056.17 1.92 ns

Y X S X H 6 113238.80 18873.13 0.63 ns

Y X N X H 6 162210.41 27035.07 0.91 ns

Y X S X N X H 18 378646.61 21035.92 0.71 ns

Error- II 128 3808363.86 29752.84

Total 287 1076965369.54

131

Table 30. Combine analysis of variance of shelling percentage of different corn hybrids as affected by nitrogen and sulfur



Years (Y) 1 129.62 129.62 30.51 **


Sulfur (S) 3 22.89 7.63 2.75 ns

Nitrogen (N) 3 7363.27 2454.42 886.01 **

S X N 9 58.40 6.49 2.34 *

Y X S 3 0.31 0.10 0.04 ns

Y X N 3 226.37 75.46 27.24 **

Y X S X N 9 33.73 3.75 1.35 ns

Error- I 60 166.21 2.77

Hybrids (H) 2 400.50 200.25 106.83 **

S X H 6 15.94 2.66 1.42 ns

N X H 6 204.77 34.13 18.21 **

S X N X H 18 44.76 2.49 1.33 ns

Y X H 2 33.56 16.78 8.95 **

Y X S X H 6 16.73 2.79 1.49 ns

Y X N X H 6 39.49 6.58 3.51 **

Y X S X N X H 18 44.58 2.48 1.32 ns

Error- II 128 239.93 1.87

Total 287 9058.05

132

Table 31. Combine analysis of variance for biological yield (kg ha-1) of different corn hybrids as affected by nitrogen and sulfur



level

Years (Y) 1 3521455 3521455 39.68 **

Replications 4 354984 88746

Sulfur (S) 3 3481553 1160518 0.63 ns

Nitrogen (N) 3 4189895123 1396631708 757.39 **

S X N 9 17095821 1899536 1.03 ns

Y X S 3 2034551 678184 0.37 ns

Y X N 3 79037540 26345847 14.29 **

Y X S X N 9 21126294 2347366 1.27 ns

Error- I 60 110639967 1843999

Hybrids (H) 2 1906372 953186 1.28 ns

S X H 6 2709200 451533 0.61 ns

N X H 6 43563341 7260557 9.79 **

S X N X H 18 12983296 721294 0.97 ns

Y X H 2 11492433 5746217 7.75 **

Y X S X H 6 1298559 216426 0.29 ns

Y X N X H 6 9632114 1605352 2.16 ns

Y X S X N X H 18 8912820 495157 0.67 ns

Error- II 128 94961353 741886

Total 287 4614646779

133

Table 32. Combine analysis of variance of harvest index of different corn hybrids as affected by nitrogen and sulfur during 2013

and 2014.


Years (Y) 1 16.86 16.86 8.29 *


Sulfur (S) 3 13.99 4.66 1.82 ns

Nitrogen (N) 3 8107.33 2702.44 1054.34 **

S X N 9 50.67 5.63 2.20 *

Y X S 3 6.83 2.28 0.89 ns

Y X N 3 288.27 96.09 37.49 **

Y X S X N 9 80.37 8.93 3.48 **

Error- I 60 153.79 2.56

Hybrids (H) 2 279.44 139.72 75.14 **

S X H 6 7.48 1.25 0.67 ns

N X H 6 202.27 33.71 18.13 **

S X N X H 18 17.53 0.97 0.52 ns

Y X H 2 18.34 9.17 4.93 **

Y X S X H 6 5.40 0.90 0.48 ns

Y X N X H 6 23.08 3.85 2.07 ns

Y X S X N X H 18 23.92 1.33 0.71 ns

Error- II 128 238.02 1.86 *

Total 287 9541.73

134

Table 33. Combine analysis of variance of protein (%) of different corn hybrids as affected by nitrogen and sulfur during 2013 and

2014.


Years (Y) 1 28.10 28.10 196.57 **


Sulfur (S) 3 0.31 0.10 0.85 ns

Nitrogen (N) 3 340.30 113.43 939.76 **

S X N 9 0.88 0.10 0.81 ns

Y X S 3 0.91 0.30 2.53 ns

Y X N 3 1.39 0.46 3.84 *

Y X S X N 9 0.96 0.11 0.88 ns

Error- I 60 7.24 0.12

Hybrids (H) 2 18.07 9.04 108.33 **

S X H 6 0.50 0.08 1.00 ns

N X H 6 8.70 1.45 17.38 **

S X N X H 18 1.19 0.07 0.80 ns

Y X H 2 0.08 0.04 0.48 ns

Y X S X H 6 0.69 0.11 1.37 ns

Y X N X H 6 1.07 0.18 2.14 ns

Y X S X N X H 18 1.31 0.07 0.87 ns

Error- II 128 10.68 0.08

Total 287 422.96

135

Table 34. Combine analysis of variance of oil (%) of different corn hybrids as affected by nitrogen and sulfur during 2013 and

2014.


Years (Y) 1 0.04 0.04 1.05 ns


Sulfur (S) 3 109.23 36.41 806.71 **

Nitrogen (N) 3 0.26 0.09 1.91 ns

S X N 9 2.29 0.25 5.64 **

Y X S 3 0.04 0.01 0.30 ns

Y X N 3 0.01 0.00 0.07 ns

Y X S X N 9 0.06 0.01 0.15 ns

Error- I 60 2.71 0.05

Hybrids (H) 2 2.72 1.36 46.89 **

S X H 6 1.07 0.18 6.16 **

N X H 6 0.21 0.03 1.20 ns

S X N X H 18 0.41 0.02 0.79 ns

Y X H 2 0.04 0.02 0.72 ns

Y X S X H 6 0.07 0.01 0.40 ns

Y X N X H 6 0.29 0.05 1.65 ns

Y X S X N X H 18 0.53 0.03 1.02 ns

Error- II 128 3.71 0.03

Total 287 123.83

136

Table 35. Combine analysis of variance of mineral nitrogen in soil of different corn hybrids as affected by nitrogen and sulfur



Years (Y) 1 1971.40 1971.40 1127.07 **


Sulfur (S) 3 2.03 0.68 0.09 ns

Nitrogen (N) 3 11635.15 3878.38 519.52 **

S X N 9 51.56 5.73 0.77 ns

Y X S 3 3.53 1.18 0.16 ns

Y X N 3 780.82 260.27 34.86 **

Y X S X N 9 87.67 9.74 1.30 ns

Error- I 60 447.92 7.47

Hybrids (H) 2 51.52 25.76 16.17 **

S X H 6 9.98 1.66 1.04 ns

N X H 6 25.54 4.26 2.67 *

S X N X H 18 30.37 1.69 1.06 ns

Y X H 2 8.05 4.02 2.53 ns

Y X S X H 6 16.52 2.75 1.73 ns

Y X N X H 6 17.96 2.99 1.88 ns

Y X S X N X H 18 29.72 1.65 1.04 ns

Error- II 128 203.87 1.59

Total 287 15380.62

137

Table 36. Combine analysis of variance of soil sulfur of different corn hybrids as affected by nitrogen and sulfur during 2013 and

2014.


Years (Y) 1 5.73 5.73 2.17 ns


Sulfur (S) 3 6781.55 2260.52 921.03 **

Nitrogen (N) 3 67.51 22.50 9.17 **

S X N 9 83.70 9.30 3.79 **

Y X S 3 2.51 0.84 0.34 ns

Y X N 3 4.10 1.37 0.56 ns

Y X S X N 9 4.51 0.50 0.20 ns

Error- I 60 147.26 2.45

Hybrids (H) 2 24.99 12.50 3.89 *

S X H 6 36.31 6.05 1.88 ns

N X H 6 37.66 6.28 1.95 ns

S X N X H 18 90.73 5.04 1.57 ns

Y X H 2 3.30 1.65 0.51 ns

Y X S X H 6 13.09 2.18 0.68 ns

Y X N X H 6 5.20 0.87 0.27 ns

Y X S X N X H 18 12.21 0.68 0.21 ns

Error- II 128 411.00 3.21

Total 287 7741.91

138

Table 37. Combine analysis of variance of tissue sulfur of different corn hybrids as affected by nitrogen and sulfur during 2013

and 2014.


Years (Y) 1 0.0022 0.0022 53.0664 **


Sulfur (S) 3 2.3326 0.7775 4992.2112 **

Nitrogen (N) 3 0.0020 0.0007 4.3110 *

S X N 9 0.0039 0.0004 2.8122 **

Y X S 3 0.0016 0.0005 3.3576 **

Y X N 3 0.0006 0.0002 1.2720 ns

Y X S X N 9 0.0034 0.0004 2.4548 *

Error- I 60 0.0093 0.0002

Hybrids (H) 2 0.0004 0.0002 1.7484 ns

S X H 6 0.0006 0.0001 0.7685 ns

N X H 6 0.0016 0.0003 2.1172 ns

S X N X H 18 0.0010 0.0001 0.4719 ns

Y X H 2 0.0003 0.0001 1.1036 ns

Y X S X H 6 0.0003 0.0001 0.4511 ns

Y X N X H 6 0.0001 0.0000 0.1571 ns

Y X S X N X H 18 0.0003 0.0000 0.1428 ns

Error- II 128 0.0157 0.0001

Total 287 2.38

139

Table 38. Combine analysis of variance of total nitrogen in tissue of different corn hybrids as affected by nitrogen and sulfur



level

Years (Y) 1 0.01 0.01 3.86 ns


Sulfur (S) 3 0.12 0.04 3.61 *

Nitrogen (N) 3 35.72 11.91 1112.87 **

S X N 9 0.26 0.03 2.65 *

Y X S 3 0.03 0.01 0.86 ns

Y X N 3 0.07 0.02 2.12 ns

Y X S X N 9 0.07 0.01 0.68 ns

Error- I 60 0.64 0.01

Hybrids (H) 2 0.12 0.06 26.06 **

S X H 6 0.01 0.00 0.66 ns

N X H 6 0.04 0.01 2.89 *

S X N X H 18 0.07 0.00 1.67 ns

Y X H 2 0.00 0.00 0.36 ns

Y X S X H 6 0.00 0.00 0.15 ns

Y X N X H 6 0.00 0.00 0.33 ns

Y X S X N X H 18 0.03 0.00 0.74 ns

Error- II 128 0.29 0.00

Total 287 37.46

Documents

BY ABDUL QAHAR DOCTOR OF PHILOSOPHY IN AGRICULTURE …prr.hec.gov.pk/jspui/bitstream/123456789/7846/1/Abdul Qahar Ph.D Thesis...NITROGEN AND SULFUR FERTILIZATION FOR ENHANCING GRAIN