Microsoft Word - Initial pagesIn the name of Allah, the most Beneficent, the Merciful
II
DETERMINING FORAGE PRODUCTION POTENTIAL OF MAIZE SOWN AS A MIXTURE WITH DIFFERENT
LEGUMES UNDER DIFFERENT NITROGEN APPLICATIONS
By
95-ag-1214
A thesis submitted in partial fulfillment of the requirements for the degree of
DOCTOR OF PHILOSOPHY
2010
III
The Controller of Examinations, University of Agriculture, Faisalabad. We, the supervisory committee, certify that the contents and form of thesis
submitted by Mr. Muhammad Ibrahim, Regd. No. 95-ag-1214 have been
found satisfactory and recommend that it be processed for evaluation by
external examiner(s) for the award of degree.
Supervisory committee:
TO
V
ACKNOWLEDGMENTS All the praises are credited to the sole creator of the entire universe
ALMIGHTY ALLAH, The Most Beneficent, The Most Merciful and The Most Compassionate, Who granted me the power of vision and wisdom to unknot the mysteries of the universe in a more systematic manner what people call it SCIENCE. And only by the grace of ALLAH, I was capable to make this material contribution to already existing ocean of knowledge. I invoke Allah’s blessings and peace for my beloved Prophet Hazrat MUHAMMAD (Peace Be upon Him), who is eternally present torch of direction and knowledge for humanity as a whole and whose honorable and spiritual teachings enlightened my heart, soul and mind.
I desire to widen most sincere thanks and deep sense of obligations to my supervisor, Dr. Muhammad Ayub, Professor, Department of Agronomy, UAF. This manuscript has found its way to a significant close due to his energetic supervision, and masterly advice.
I feel much happiness to utter the heartiest gratitude and sincere admiration to Dr. Asif Tanveer, Professor, Department of Agronomy, for his generous guidance, kind behavior, cooperation and priceless suggestions on this piece of work. In spite of his multifarious duties I enjoyed his friendly company which made the research period unforgettable era.
I wish to record my heartfelt appreciation to Dr. Muhammad Yaseen, Associate Professor, Institute of Soil and Environmental Sciences, member of supervisory committee for his affectionate behavior and moral support throughout the course of my studies.
It is very difficult to record my appreciation and thanks for Dr. Muhammad Tahir, (Assistant professor, Dept. of Agronomy, UAF), Dr. Muhammad Farooq (Assistant professor, Dept. of Agronomy, UAF) and Mr. Muhammad Saeed Imran (Lecturer, UAF, Sub-Campus, Toba Tek Singh) for providing technical and moral support, encouragement during the write-up of this manuscript. Their love is always a source of inspiration for me.
The author is obligate to Dr. Abdul Khaliq (Associate professor, Dept. of
Agronomy, UAF) and all his colleagues at UAF, Sub-Campus TT Singh for their friendly behavior, nice collaboration and help they provided as and when needed. And cooperation of research fellow Mr. Zafar Iqbal is unforgettable.
The author is also thankful to all staff members of Agronomy for their
cooperation and help during entire period of research. The cooperation and support of my whole family especially my uncle Dr. A. D. Nadeem Chaudhry is unforgettable throughout my life period.
Muhammad Ibrahim
No. TITLE Page
No. I ACKNOWLEDGEMENTS V II CONTENTS VI III LIST OF TABLES IX IV LIST OF FIGURES XI II V LIST OF ABBREVIATIONS XIV VI ENGLISH AND BOTANICAL NAMES OF CROPS IN THE
MANUSCRIPT XV
VII GROWTH HABITAT, DISEASES AND PESTS OF CROPS IN MANUSCRIPT
XVI
GROWTH HABITAT, DISEASES AND PESTS OF CROPS USED IN RESEARCH
XVII
*** ABSTRACT 1 1 INTRODUCTION 2 2 REVIEW OF LITERATURE 6 *** MIXED CROPPING 6 2.1 SIGNIFICANCE OF MIXED CROPPING 8 2.1.1 Soil fertility 9 2.1.2 Lack of risk 9 2.1.3 Tolerance against adverse climatic conditions 9 2.1.4 Better use of labor 9 2.1.5 Weed control 10 2.1.6 Complementary effects 10 2.1.7 Soil conservation 10 2.1.8 Prevention of lodging 11 2.1.9 Financial stabilization 11 2.1.10 Control on diseases and insect pest 11 2.1.11 Transfer of nitrogen from legume to non-legume 12 2.1.12 Yield and yield components 13 2.1.13 Quality of product 19 2.2 EFFECT OF COMPONENT SEED RATIO / PLANT DENSITY 20 2.2.1 Growth, yield and yield attributes of the component crops 21 2.2.2 Mixed yield, land equivalent ratio and quality traits 27 2.3 NITROGEN MANAGEMENT 33 2.3.1 Effect of nitrogen application on cereal/non legumes 33 2.3.2 Effect of nitrogen application on legumes 38 2.3.3 Effect of nitrogen application on mixtures 40 3 MATERIALS AND METHODS 45 **** EXPERIMENTAL SITE 45 3.1 Soil characteristics 45 3.2 Meteorological data 45 3.3 EXPERIMENTS 47 3.3.1 Experiment No 1 47 3.3.2 Experiment No 2 48
VII
3.4 Layout 49 3.5 Crop husbandry 49 3.5.1 Seed bed preparation 49 3.5.2 Crops and their seed rates 49 3.5.3 Time and method of sowing 50 3.5.4 Fertilizer application 50 3.5.5 Irrigation 50 3.5.6 Harvesting 50 3.6 Data collection 50 3.6.1 Observations recorded 51 3.6.2 Procedures for recording data 52 A. AGRONOMIC PARAMETERS 52 B. PHYSIOLOGICAL PARAMETERS 54 C. QUALITY PARAMETERS 55 D. COMPETITIVE FUNCTION 57 E. ECONOMIC ANALYSIS 58 3.7 STATISTICAL ANALYSIS 58 4 RESULTS AND DISCUSSION 59 4.1 EXPERIMENT NO. I 59 4.1.1 AGRONOMIC TRAITS OF FORAGE MAIZE 59 4.1.1.1 Emergence count (m-2) 59 4.1.1.2 Number of leaves per plant 61 4.1.1.3 Plant height of forage maize (cm) 64 4.1.1.4 Stem diameter of forage maize (cm) 67 4.1.1.5 Green forage yield of maize (t ha-1) 70 4.1.1.6 Dry matter yield of maize (t ha-1) 73 4.1.2. PHYSIOLOGICAL BEHAVIOR OF FORAGE MAIZE 75 4.1.2.1 Leaf area index of forage maize 75 4.1.2.2 Final leaf area duration of forage maize (days) 78 4.1.2.3 Mean crop growth rate of forage maize (g m-2d-1) 80 4.1.3. QUALITY TRAITS OF FORAGE MAIZE 82 4.1.3.1 Crude protein percentage of forage maize 82 4.1.3.2 Crude fibre percentage of forage maize 84 4.1.3.3 Ether extractable fat percentage of forage maize 84 4.1.3.4 Total ash percentage of forage maize 87 4.1.4. AGRONOMIC TRAITS OF FORAGE LEGUMES 89 4.1.4.1 Emergence count (m-2) 89 4.1.4.2 Plant height of forage legumes (cm) 91 4.1.4.3 Green forage yield of legumes (t ha-1) 93 Green fresh weight of legumes (kg m-2) 93 4.1.4.4 Dry matter yield of legumes (t ha-1) 96 Dry weight of legumes (g m-2) 96 4.1.5. QUALITY TRAITS OF FORAGE LEGUMES 99 4.1.5.1 Crude protein percentage of forage legumes 99 4.1.5.2 Crude fibre percentage of forage legumes 99 4.1.5.3 Ether extractable fat percentage of forage legumes 101 4.1.5.4 Total ash percentage of forage legumes 104
VIII
4.1.6. MIXED YIELD AND QUALITY 104 4.1.6.1 Mixed (maize+legume) green forage yield (t ha-1) 104 4.1.6.2 Mixed (maize+legume) dry matter yield (t ha-1) 108 4.1.6.3 Crude protein percentage of mixed (maize+legume) forage 110 4.1.6.4 Crude fibre percentage of mixed (maize+legume) forage 112 4.1.6.5 Ether extractable fat percentage of mixed (maize+legume) forage 112 4.1.6.6 Total ash percentage of mixed (maize+legume) forage 114 4.1.7. COMPETITIVE FUNCTION 116 4.1.7.1 Land equivalent ratio (LER) 116 4.2. EXPERIMENT NO. II 120 4.2.1. AGRONOMIC TRAITS OF FORAGE MAIZE 120 4.2.1.1 Emergence count (m-2) 120 4.2.1.2 Number of leaves per plant 122 4.2.1.3 Plant height of forage maize (cm) 126 4.2.1.4 Stem diameter of forage maize (cm) 132 4.2.1.5 Green forage yield of maize (t ha-1) 136 4.2.1.6 Dry matter yield of maize (t ha-1) 140 4.2.2. PHYSIOLOGICAL CHARACTERISTICS OF FORAGE MAIZE 144 4.2.2.1 Leaf area index of forage maize 144 4.2.2.2 Final leaf area duration of forage maize (days) 149 4.2.2.3 Mean crop growth rate of forage maize (g m-2d-1) 152 4.2.3. QAULITY TRAITS OF FORAGE MAIZE 155 4.2.3.1 Crude protein percentage of forage maize 155 4.2.3.2 Crude fibre percentage of forage maize 157 4.2.3.3 Ether extractable fat percentage of forage maize 162 4.2.3.4 Total ash percentage of forage maize 164 ****** Relationship of dry matter yield with yield contributing parameters
and quality traits of forage maize 167
4.2.4. AGRONOMIC TRAITS OF FORAGE LEGUMES 168 4.2.4.1 Emergence count of forage legumes (m-2) 168 4.2.4.2 Plant height of forage legumes (cm) 171 4.2.4.3 Green forage yield of legumes (t ha-1) 172 4.2.4.4 Dry matter yield of legumes (t ha-1) 179 4.2.5. QUALITY TRAITS OF FORAGE LEGUMES 182 4.2.5.1 Crude protein percentage of forage legumes 182 4.2.5.2 Crude fibre percentage of forage legumes 184 4.2.5.3 Ether extractable fat percentage of forage legumes 186 4.2.5.4 Total ash percentage of forage legumes 188 4.2.6. MIXED YIELD 191 4.2.6.1 Mixed (maize+legume) green forage yield (t ha-1) 191 4.2.6.2 Mixed (maize+legume) dry matter yield (t ha-1) 194 4.2.7 Economic analysis 198 5 SUMMARY 202 6 LITERATURE CITED 207 ****** APPENDICES 246
IX
No Description Page
No. ***** MATERIALS AND METHODS 3.1 Physico-chemical soil analysis of the experimental site during the year
2005 and 2006 46
3.2 Summary of climatic norms during the cropping season of 2005 and 2006
46
3.3 Cultivar and seed rate of the crops for sole cropping 49 ***** EXPERIMENT NO. I 4.1 Effect of seed ratios of different maize-legume mixtures on emergence
count (m-2) of forage maize 60
4.2 Effect of seed ratios of different maize-legume mixtures on number of leaves per plant of forage maize
62
4.3 Effect of seed ratios of different maize-legume mixtures on plant height (cm) of forage maize
65
4.4 Effect of seed ratios of different maize-legume mixtures on stem diameter (cm) of forage maize
68
4.5 Effect of seed ratios of different maize-legume mixtures on green forage yield (t ha-1) of maize
72
4.6 Effect of seed ratios of different maize-legume mixtures on dry matter yield (t ha-1) of maize
74
4.7 Effect of seed ratios of different maize-legume mixtures on leaf area index (LAI) of forage maize
76
4.8 Effect of seed ratios of different maize-legume mixtures on final leaf area duration (days) of forage maize
79
4.9 Effect of seed ratios of different maize-legume mixtures on mean crop growth rate (g m-2d-1) of forage maize
81
4.10 Effect of seed ratios of different maize-legume mixtures on crude protein (%) of forage maize
83
4.11 Effect of seed ratios of different maize-legume mixtures on crude fibre (%) of forage maize
85
4.12 Effect of seed ratios of different maize-legume mixtures on ether extractable fat (%) of forage maize
86
4.13 Effect of seed ratios of different maize-legume mixtures on total ash (%) of forage maize
88
4.14 Effect of seed ratios of different maize-legume mixtures on emergence count (m-2) of forage legumes
90
4.15 Effect of seed ratios of different maize-legume mixtures on plant height (cm) of forage legumes
92
4.16 Effect of seed ratios of different maize-legume mixtures on green forage yield (t ha-1) of legumes
94
4.17 Effect of seed ratios of different maize-legume mixtures on dry matter yield (t ha-1) of legumes
97
X
4.18 Effect of seed ratios of different maize-legume mixtures on crude protein (%) of forage legumes
100
4.19 Effect of seed ratios of different maize-legume mixtures on crude fibre (%) of forage legumes
102
4.20 Effect of seed ratios of different maize-legume mixtures on ether extractable fat (%) of forage legumes
103
4.21 Effect of seed ratios of different maize-legume mixtures on total ash (%) of forage legumes
105
4.22 Effect of seed ratios of different maize-legume mixtures on mixed green forage yield (t ha-1)
107
4.23 Effect of seed ratios of different maize-legume mixtures on mixed dry matter yield (t ha-1)
109
4.24 Effect of seed ratios of different maize-legume mixtures on crude protein (%) of mixed (maize+legume) forage
111
4.25 Effect of seed ratios of different maize-legume mixtures on crude fibre (%) of mixed (maize+legume) forage
113
4.26 Effect of seed ratios of different maize-legume mixtures on ether extractable fat (%) of mixed (maize+legume) forage
115
4.27 Effect of seed ratios of different maize-legume mixtures on total ash (%) of mixed (maize+legume) forage
117
4.28 Effect of seed ratios of different maize-legume mixtures on land equivalent ratio (two year averaged data)
119
***** EXPERIMENT NO. II 4.29 Influence of nitrogen application on emergence count (m-2) of forage
maize sown alone and in mixture with legumes during 2005 and 2006 121
4.30 Influence of nitrogen application on number of leaves per plant of forage maize sown alone and in mixture with legumes during 2005 and 2006
123
4.31 Influence of nitrogen application on plant height (cm) of forage maize sown alone and in mixture with legumes during 2005
127
4.32 Influence of nitrogen application on plant height (cm) of forage maize sown alone and in mixture with legumes during 2006
129
4.33 Influence of nitrogen application on stem diameter (cm) of forage maize sown alone and in mixture with legumes during 2005 and 2006
133
4.34 Influence of nitrogen application on green forage yield (t ha-1) of maize sown alone and in mixture with legumes during 2005
138
4.35 Influence of nitrogen application on green forage yield (t ha-1) forage maize sown alone and in mixture with legumes during 2006
139
4.36 Influence of nitrogen application on dry matter yield (t ha-1) of maize sown alone and in mixture with legumes during 2005
142
4.37 Influence of nitrogen application on dry matter yield (t ha-1) of maize sown alone and in mixture with legumes during 2006
143
4.38 Influence of nitrogen application on leaf area index (LAI) of forage maize sown alone and in mixture with legumes during 2005 and 2006
145
4.39 Influence of nitrogen application on final leaf area duration (days) of forage maize sown alone and in mixture with legumes during 2005
150
4.40 Influence of nitrogen application on final leaf area duration (days) of forage maize sown alone and in mixture with legumes during 2006
151
XI
4.41 Influence of nitrogen application on mean crop growth rate (g m-2 d-1) of forage maize sown alone and in mixture with legumes during 2005
153
4.42 Influence of nitrogen application on mean crop growth rate (g m-2 d-1) of forage maize sown alone and in mixture with legumes during 2006
154
4.43 Influence of nitrogen application on crude protein (%) of forage maize sown alone and in mixture with legumes during 2005
158
4.44 Influence of nitrogen application on crude protein (%) of forage maize sown alone and in mixture with legumes during 2006
158
4.45 Influence of nitrogen application on crude fibre (%) of forage maize sown alone and in mixture with legumes during 2005
160
4.46 Influence of nitrogen application on crude fibre (%) of forage maize sown alone and in mixture with legumes during 2006
161
4.47 Influence of nitrogen application on ether extractable fat (%) of forage maize sown alone and in mixture with legumes during 2005 and 2006
163
4.48 Influence of nitrogen application on total ash (%) of forage maize sown alone and in mixture with legumes during 2005
165
4.49 Influence of nitrogen application on total ash (%) of forage maize sown alone and in mixture with legumes during 2006
166
4.50 Relationship of dry matter yield with yield contributing parameters and quality traits of forage maize during 2005 and 2006
169
4.51 Influence of nitrogen application on emergence count (m-2) of legumes sown in mixture with forage maize during 2005 and 2006
170
4.52 Influence of nitrogen application on plant height (cm) of legumes sown in mixture with forage maize during 2005
173
4.53 Influence of nitrogen application on plant height (cm) of legumes sown in mixture with forage maize during 2006
174
4.54 Influence of nitrogen application on green forage yield (t ha-1) of legumes sown in mixture with forage maize during 2005
178
4.55 Influence of nitrogen application on green forage yield (t ha-1) of legumes sown in mixture with forage maize during 2006
178
4.56 Influence of nitrogen application on dry matter yield (t ha-1) of legumes sown in mixture with forage maize during 2005
181
4.57 Influence of nitrogen application on dry matter yield (t ha-1) of legumes sown in mixture with forage maize during 2006
181
4.58 Influence of nitrogen application on crude protein (%) of legumes sown in mixture with forage maize during 2005
183
4.59 Influence of nitrogen application on crude protein (%) of legumes sown in mixture with forage maize during 2006
183
4.60 Influence of nitrogen application on crude fibre (%) of legumes sown in mixture with forage maize during 2005 and 2006
185
4.61 Influence of nitrogen application on ether extractable fat (%) of legumes sown in mixture with forage maize during 2005 and 2006
187
4.62 Influence of nitrogen application on total ash (%) of legumes sown in mixture with forage maize during 2005
189
4.63 Influence of nitrogen application on total ash (%) of legumes sown in mixture with forage maize during 2006
190
4.64 Influence of nitrogen application on mixed green forage yield (t ha-1) of maize sown alone and in mixture with legumes during 2005
192
XII
4.65 Influence of nitrogen application on mixed green forage yield (t ha-1) of maize sown alone and in mixture with legumes during 2006
193
4.66 Influence of nitrogen application on mixed dry matter yield (t ha-1) of maize sown alone and in mixture with legumes during 2005
196
4.67 Influence of nitrogen application on mixed dry matter yield (t ha-1) of maize sown alone and in mixture with legumes during 2006
197
4.68 Economic analysis 2005 200 4.69 Economic analysis 2006 201
XIII
LIST OF FIGURES
Figur e No
Description Page No.
4.1 Periodic number of leaves of forage maize as influenced by seed ratios of different maize-legume mixtures during (a) 2005 and (b) 2006
63
4.2 Periodic plant height of forage maize as influenced by seed ratios of different maize-legume mixtures during (a) 2005 and (b) 2006
66
4.3 Periodic stem diameter of forage maize as influenced by seed ratios of different maize-legume mixtures during (a) 2005 and (b) 2006
69
4.4 Periodic leaf area index of forage maize as influenced by seed ratios of different maize-legume mixtures during (a) 2005 and (b) 2006
77
4.5 Periodic fresh weight of forage legumes as influenced by seed ratios of different maize-legume mixtures during (a) 2005 and (b) 2006
95
4.6 Periodic dry weight of forage legumes as influenced by seed ratios of different maize-legume mixtures during (a) 2005 and (b) 2006
98
4.7 Periodic number of leaves of forage maize as influenced by different nitrogen levels during (a) 2005 and (b) 2006
124
4.8 Periodic number of leaves of forage maize as influenced by different maize-legume mixtures during (a) 2005 and (b) 2006
125
4.9 Periodic plant height of forage maize as influenced by different nitrogen levels during (a) 2005 and (b) 2006
130
4.10 Periodic plant height of forage maize as influenced by different maize-legume mixtures during (a) 2005 and (b) 2006
131
4.11 Periodic stem diameter of forage maize as influenced by different nitrogen levels during (a) 2005 and (b) 2006
134
4.12 Periodic stem diameter of forage maize as influenced by different maize-legume mixtures during (a) 2005 and (b) 2006
135
4.13 Periodic leaf area index of forage maize as influenced by different nitrogen levels during (a) 2005 and (b) 2006
146
4.14 Periodic leaf area index of forage maize as influenced by different maize-legume mixtures during (a) 2005 and (b) 2006
147
4.15 Periodic plant height of different forage legumes as influenced by different nitrogen levels during (a) 2005 and (b) 2006
175
4.16 Periodic plant height of different forage legumes as influenced by maize-legume mixtures during (a) 2005 and (b) 2006
176
XIV
% Percent %age Percentage
@ at the rate of < Less than > greater than ≤ Lesser or equal to
ADF Acid detergent fibre CGR Crop growth rate CP Crude protein CF Crude fibre ºC Centigrade cm Centimeter cm2 Square centimeter cm-2 Per square centimeter DAS Days after sowing DM Dry matter
dSm-1 Desi semen per meter EEF Ether extractable fat
Feddan It is unit of area and used in Egypt, Sudan, and Syria.
FYM Farm yard manure ha Hectare
ha-1 Per hectare g Gram
g m-2 d-1 Grams per meter square per day K Potassium kg Kilogram
kg ha-1 Kilogram per hectare L0 Maize alone L1 Maize+cowpea L2 Maize+sesbania L3 Maize+cluster bean La LER for the crop "a"
LAD Leaf area duration LAI Leaf area index Lb LER for the crop "b"
LER Land equivalent ratio LSD Least significant difference m Meter m2 Meter square m-2 Per meter square mm Millimeter
XV
N Nitrogen N0 0 kg N ha-1 N1 50 kg N ha-1 N2 100 kg N ha-1 N3 150 kg N ha-1
NAR Net assimilation rate NDF Neutral detergent fibre NS Non-significant P Phosphorus P Probability
P2O5 Phosphorus Plant-1 Per plant Ppm Parts per million q ha-1 Quintal per hectare RGR Relative growth rate R.H. Relative humidity Rs. Rupees
SR1…….SR13 Seed ratio 1……..Seed ratio 13 SOP Sulphate of Potash SSP Single super phosphate Y Year t Tonnes
TDM Total dry matter t ha-1 Tonnes per hectare W Weight
Yaa Pure stand yield of crop "a" Yab Yield of crop "a" Yba Yield of crop "b" Ybb Pure stand yield of crop "b"
XVI
ENGLISH AND BOTANICAL NAMES OF CROPS USED IN THE MANUSCRIPT
English name Botanical name Alfalfa Medicago sativa Barley Hordeum vulgare Pearl millet Pennisetum typhoides Bilatidhonia Eryngium foetidum Chickpea/gram Cicer arientinum. Cowpea Vigna unguiculata Cluster bean Cymopsis tetragonoloba Cassava Manihot esculenta Crantz Elephant grass Saccharum ravennae Egyptian clover Trifolium alenxandrinum Faba bean Vicia faba Green bean Phaseolus vulgaris Groundnut Arachis hypogea Little millet Panicum sumatrense Lentil Lens culinaris Medik Maize Zea mays Mash bean (Green gram) Vigna radiata Mazenta Zea mays L. x Zea mexicana Moth bean Vigna aconitifolia Mung bean Vigna mungo Oat Avena sativa Pea Pisum sativum Pearl millet Pennisetum glaucum Pigeon pea Cajanus cajan Rapeseed Brassica napus Rice bean Vigna umbellate Sesame Sesamum indicum Sesbania Sesbania sesban Sorghum Sorghum bicolor Soybean Glycine max Sunflower Helianthus annuus Sudan grass Sorghum bicolor Var. sudanense Taro Colocasia esculenta (L.) Schott Tephrosia Tephrosia vogelii Vetch Vicia sativa Wheat Triticum aestivum
XVII
GROWTH HABITAT, DISEASES AND PESTS OF CROPS USED IN RESEARCH
English name
Maize • Maize is erect growing plant with thick stem.
• It has long and wider leaves and leaf consists of a sheath and a broad blade.
• Its male or terminal inflorescence called tassel.
• It has fibrous root system.
Seed rot and seedling blight Root and stalk rots Leaf spots and leaf blights Smuts and ear and kernal rots
Stalk borer, maize earworm, Shoot fly, Corn leaf aphid, Army worm, Cut worms
Cowpea • It has many types, erect, semi erect, trailing and climbing (in this study trailing was used).
• Flowers are white, white with purple marking.
• Leaves are trifoliate with ovate or lanceolate leaflets.
• It has nodulated tap root system.
Fungal disease “anthracnose” often attacks the cowpea. Scab and leaf smut.
Jassid, Aphids, beetles and white fly. Army worm is also a major pest.
Sesbania • Sesbania is an erect, fast growing annual legume plant.
• It typically grows to a height of 3-10 feet (1-3 meters).
• It has large leaves i.e. 4-12 inches long with 20-70 leaflets per leaf.
• Flowers are about 15-20 mm long and are yellowish in color, and strongly speckled with purplish brown.
• It has slender, quadrangular pods, about 6-8 inches (15-20 cm) long and 3-4mm wide.
• The seeds are small and numerous, more or less orange on their attachment side, with the other surface is more or less olive-green background, speckled/blotched with black.
• It has nodulated root system.
The bacterium, Xanthomonas sesbaniae affects the stems and foliage. Roots are attacked by nematodes.
Leaf-eating beetle, larvae of Azygophelps scalaris bore, bud beetle, sesbania seed weevil and sesbania stem borer
Cluster bean
• Cluster bean is erect growing plant • It has distinctive spikey growth habit and
upright pods • Its plants are 2.30 to 9 feet in height. Plants are also grown for the cattle fodders or green manuring crops due to its succulence while young flesh green tender pods used for vegetable purposes.
Wilt is common disease of cluster bean
Jassid is serious pest of cluster bean.
1
ABSTRACT
Two field experiments to study the agro-quantitative and qualitative response of forage maize sown alone and as a mixture with forage legumes were conducted at the Agronomic Research Area, University of Agriculture, Faisalabad, Pakistan, during the year 2005 and 2006. The sole crops and blended seed mixtures were sown in 30 cm apart rows with the help of single row hand drill. Experiment-I was replicated three times in randomized complete block design (RCBD), while the experiment-II was laid out in randomized complete block design with factorial arrangement, measuring a net plot size of 2.4 m x 8 m. First experiment comprised of thirteen treatments i.e. maize alone (100%), 75%maize + 25%cowpea, 50%maize + 50%cowpea, 25%maize + 75%cowpea, cowpea alone (100%), 75%maize + 25%sesbania, 50%maize + 50%sesbania, 25%maize + 75%sesbania, sesbania alone (100%), 75%maize + 25%cluster bean, 50%maize + 50%cluster bean, 25%maize + 75%cluster bean and cluster bean alone (100%). Mixed cropping of maize with different legumes significantly affected the growth, yield and quality of forage. The maize sown in mixture with sesbania at seed ratio of 75%+25% produced significantly higher mixed green and dry matter yield than all other seed ratios of maize in combination with any legume. The yields of all sole legumes (Cowpea, Sesbania and Cluster bean) were significantly lower than sole maize. The lowest green forage yield (16.92 t ha-1) and dry matter yield (3.52 t ha-1) was recorded when cluster bean was sown as sole crop. All maize + sesbania produced higher CP% and EEF% of mixed forage than mixtures of maize with cowpea and cluster bean at similar seed ratios. Land equivalent ratio was also highest in maize + sesbania mixture at 75:25 seed ratio. In the second experiment response of forage maize sown alone and mixture with different legumes i.e. cowpea, sesbania and cluster bean at seed ratio of 75% + 25%was evaluated at nitrogen levels of 0, 50, 100 and 150 kg ha-1. The forage and dry matter yield of sole maize was increased significantly up to 150 kg N ha-1, while the application of 150 kg N ha-1 to all maize-legume mixtures had a depressing effect on yields. Maize + sesbania mixture fertilized at 100 kg N ha-1 gave the highest mixed forage yield, dry matter yield and economic benefits (Net benefit and BCR).
2
CHAPTER-1 INTRODUCTION
Livestock sector is an important component of agriculture in Pakistan. But
the government of Pakistan has given very little attention to the livestock and
dairy sectors in the past, although livestock accounts for 51.8% of the agriculture
and it contributes about 11.29% of the total GDP. Livestock and dairy industry
needs special attention because it affects the lives of 30-35 million people in rural
areas. In Pakistan, livestock population is about 29.9 million buffaloes, 33.0
million cattle, 27.4 million sheep, 58.3 million goats, and 6.1 million other animals
(GOP, 2009a), which provides dietary requirements to millions of people. In
Pakistan, the population pressure is increasing day by day and is expected to
increase to 234 millions by 2005. According to Sheikh et al. (2005) the land
availability has declined to about 0.15 ha per capita and is forecast to shrink to
0.06 ha over time. The area under fodder crops in Pakistan is only 2.46 million
hectares, with a forage production of 55.06 million tonnes giving an average yield
of 22.38 t ha-1 (GOP, 2009b), which is insufficient to meet the requirements of the
livestock. Fodder scarcity is considered a major limiting factor for the prosperous
livestock industry in Pakistan, as the available fodder supply is 1/3 less than the
actual needs (Younas and Yaqoob, 2005). According to Chaudhary (1995),
animals in Pakistan are facing a deficiency of 25% in total digestible nutrients and
40% in digestible protein. Due to poor quality and low green fodder availability,
milk and meat production is not sufficient to fulfill the requirements of the
country. So the Government is spending million of rupees on the import of milk
and milk products every year.
In Pakistan, conventional fodder crops which are grown in kharif season
include sorghum, millet, maize, cowpea, cluster bean, sesbania, sudan grass and
new fodder crops like rice bean, mazenta, bajra napier hybrid and elephant grass.
3
Maize is one of the most important forage crop being grown under both irrigated
and barani conditions and is an important constituent of cattle fodder and poultry
feed. It is an indispensable part of human diet and animal feed (Maiti and Wesche-
Ebeling, 1998). The average forage yield of maize in Pakistan is very low and this
is due to substandard methods of cultivation, poor crop stand/suboptimal plant
density, low yielding varieties, non ratooning ability of maize, inadequate water
supply, imbalance and low application of fertilizers.
Cereal forage and grains are also considered poor in protein and essential
amino acids (Cherney and Marten, 1982; Bhatia and Rabson, 1987; Ahmad,
2006). Mixed cropping, especially with legumes can improve both forage quality
and yield because legumes are a good source of protein (Moreira, 1989; Ahmad et
al., 2006; Iqbal et al., 2006a). The growing of cereal fodders in mixtures with
legumes enhanced fodder palatability and digestibility (Chaudhary and Hussain,
1985; Ahmad et al., 2006). The use of legumes and non-legume mixtures may
result in more protein production and thus reduce the need for purchasing protein
supplement (Robinson, 1960; Carr et al., 1998; Ngongoni et al., 2007). Mixed
cropping with legumes may also improve soil fertility through the addition of
nitrogen from the component legume (Eaglesham et al., 1981; Berg, 1990; Dung
et al., 2005). The percentage of nitrogen fixed by the legume component that is
transferred to a non-legume component may vary from 0-75% (Whitehead, 1970).
Fujita et al. (1990b) and Clark and Myers (1994) have also reported the transfer of
the fixed N from legume to the associated non-legume component. Legumes can
improve the yield of cereals by increasing the N availability for uptake (Giller,
2001) because legumes are the alternate of nitrogen fertilizers and protein
supplements for improving dairy production (Mapiye et al., 2006). Successful
utilization of cereal-legume intercropping system depends on the selection of
species with good associative ability (Mapiye et al., 2007).
Among the various agronomic factors that may affect the yield and quality
of forage in a cereal-legume mixture, the application of nitrogen is considered to
4
be the most important (Tofinga, 1990). Nitrogen is the most deficient nutrient in
the cultivated soils of the world although it has a very important role in plant
growth as an essential constituent of cell components (Khaliq et al., 2009).
Nitrogen is an important constituent in the structure of protein in addition to being
a component of chlorophyll (Anon, 1983). The growth of legumes and nitrogen
fixation is often increased by the application of small amount of nitrogen
particularly if fertilizer is applied to provide nitrogen during the time between
exhaustion of the seed reserves and establishment of an effective nitrogen fixing
system (Diatloff, 1974). However, as the level of nitrogen applied is increased, the
number of effective nodules is reduced (Allos and Bartholomew, 1959;
Thomas and Berry, 1989). High rates of nitrogen application also increase the risk
of lodging and encourage diseases (Nannetti et al., 1990) and can also depress the
growth of cereals and legumes (Liebman, 1989). Many studies have shown the
impact of N application on leaf area index, plant height, number of leaves and
grain and forage yield (Muchow, 1988; McCullough et al., 1994; Waraich et al.,
2007) and its application rates vary widely from field to field (Cerrato and
Blackmer, 1991; Schmitt and Randall, 1994; Bundy and Andraski, 1995). The
application of nitrogen not only affects the forage yield of maize but also improves
its quality by increasing protein contents (Khandaker and Islam, 1988; Iqbal et al.,
2006b) and reducing fibre contents (Baran, 1987; Ayub et al., 2002b and 2003a).
To obtain higher yields from mixtures containing a legume component, it is vitally
important that recommendations for nitrogen are as precise as possible to ensure
the efficient utilization of this nutrient.
The relative proportion of component crops in mixture is another important
factor determining yield, quality and production efficiency of cereal-legume
mixtures (Willey and Osiru, 1972). The cereal has been described as a dominant
component and legume as a dominated component (Huxley and Maingu, 1978).
Generally taller cereals shade legumes and at high densities cause reduced growth
and yield of the companion legume (Tofinga, 1990). However, a high proportion
5
of legumes is undesirable since they normally have a low dry matter content and
are susceptible to lodging (Gilliland and Johnston, 1992; Ayub et al., 2008). The
total exclusion of legumes or their inclusion at a very low seed rate produces
nutritionally inferior forage (Ayub, et al., 2008), since the concentration of crude
protein in the mixture is reduced. Therefore, a correct balance of legume and non-
legume in a mixture is very important. Very little work has been done on
exploring the possibility of growing forage maize in mixture with legumes in
Pakistan.
The present study has, therefore been planned with the following
objectives: -
• To compare the growth, forage yield and quality of sole cropping of maize
with mixed cropping.
• To assess the impact of different seed ratios on forage yield and quality of
maize and associated legumes.
• To compare the agro-quantitative and qualitative response of maize sown
alone and in mixture with forage legumes to nitrogen applications.
6
LITERATURE MIXED CROPPING
Earlier, cropping systems were based on mixtures of desirable species to
meet the basic necessities of life like food, fibre and shelter for the welfare of the
community (Francis, 1989). Mixtures of species were chosen by the growers over
the centuries to make use of rainfall and native soil fertility, and choices were
made from the best performing combinations observed. Ayier (1949) was the
scientist who described the importance of mixed cropping on scientific basis for
the first time in the sub-continent and defined it as “A system of growing two or
more crops (or varieties) in the same field, garden or plantation, not in separate
blocks with each carrying a single crop but mixed together, occupying the same
ground and with identical cultural operations applied to the growing area. Inter
cropping remained a wide spread practice (Okigbo and Greenland, 1976) and
Willey (1979) defined intercropping as “Growing two or more crops
simultaneously on the same piece of land with a distinct row arrangements and
mixed cropping as being without a distinct row arrangements”.
Mixed cropping of legumes and non-legumes is a very common practice in
many parts of the world and particularly in the developing countries. Legumes are
the major source of protein for both humans and animals and they also contribute
nitrogen to non-legume components when grown in mixture. Tsubo et al. (2003)
reported that mixed/intercropping is a technique for small farmers and
intercropping systems of maize with legumes (soybean, cowpea, french beans and
urd beans) were superior to sole crops (Ranbir et al., 2001). Gathumbi et al.
7
(2003) suggested that to enhance subsoil N retrieval, mixing of leguminous
species must be there in the cropping system.
TERMS RELATED TO MIXED CROPPING
Some confusion exists with regard to the terminologies used to describe
complex cropping systems. The same terms have been used to describe different
systems and different terms have been used to describe the same system. The term
“mixed cropping” is frequently, with subtle semantic differences, designated as
intercropping, interplanting, mixed cultivation and poly culture (Okigbo, 1979).
Francis (1986) published a series of definition with some additional terminology.
(A) MULTIPLE CROPPING
The intensification of cropping in temporal and spatial dimensions, growing
two or more crops on the same field in one year.
(B) SEQUENTIAL CROPPING Growing two or more crops in sequence on the same field in one year. The
succeeding crop is planted after the preceding crop has been harvested. This can
result in double, triple, and quadruple cropping.
(C) INTER CROPPING Growing two or more crops simultaneously in the same field. Crop
intensification is in both temporal and spatial dimensions. There is intercrop
competition during all or part of the growing season. Intercropping can be divided
into four main types.
Growing two or more crops simultaneously with no distinct row
arrangements.
(ii) ROW INTERCROPPING
Growing two or more crops simultaneously, where one or more crops are
planted in rows
(iii) STRIP INTERCROPPING
Growing two or more crops simultaneously in different strips wide enough
to permit independent cultivation but narrow enough for the crop to interact
agronomically.
(iv) RELAY INTERCROPPING Growing two or more crops simultaneously during part of the life cycle of
each. A second crop is planted after the first crop has reached its reproductive
stage of growth but before it is ready for harvest.
2.1 SIGNIFICANCE OF MIXED CROPPING
The significance of mixtures depends upon the extent and nature of
competition between plants in mixture. Mixed cropping may be more beneficial if
the components have different maturity time and growth requirements, have
different root system or different morphology, especially in height. Growing of
more than one crop better utilizes resources in comparison to mono cropping
(Sobkowicz, 2006). Selection of crops for mixed/intercropping includes their
compatibility, low competition and ability to produce higher yield as the most
important factor (Gharineh and Telavat, 2009). Fisher (1979) compared mixed
cropping of maize-bean with mono cropping and reported several advantages of
mixed cropping. The significance of mixed cropping over sole cropping are
summarized as under:
2.1.1 SOIL FERTILITY Mixed cropping of legumes helps to maintain soil fertility status (Rao et al.,
1983). The legumes with their ability to fix atmospheric nitrogen increase the pool
of nitrogen available to both crops and will usually increase the nitrogen content
of the soil for future crops (Willey, 1979; Berg, 1990; Weil and Samaranayake,
1991; Kurdali et al., 2003; Reda et al., 2005). Farmers realize that the legumes
9
have residual benefits for maize production (Benson, 1997; Sakala, 1999).
Intercropping of forge legumes such as Leucaena leucocephala or cowpea (Vigna
unculata), with cassava enriches the soil fertility (Wanapat et al., 2005). Even
mixtures of non-legumes may conserve fertility more than sole cropping, since the
longer period that the crops are on the land will decrease the loss of fertility by
leaching and soil erosion. Intercropping of sorghum with different legumes
improved the fertility status of the soil (Ahmad, 2006). According to Gregorich et
al. (2001) legume-based cropping systems improve the soil organic matter,
thereby enhancing soil quality.
2.1.2 LACK OF RISK
Mixed cropping protects the farmer from risks and is a good insurance,
since if the one crop fails the other may survive (Walton, 1983; Droushiotis, 1989;
Francis, 1989; Ayub, 1993; Agegnehu et al., 2008).
2.1.3 TOLERANCE AGAINST ADVERSE CLIMATIC CONDITION S Crop mixtures may withstand the vagaries of the environment better than
sole crops and can therefore be less variable in yield from season to season (Rao
and Willey, 1980; Francis, 1989; Barik et al., 1998; Agegnehu et al., 2008).
2.1.4 BETTER USE OF LABOR
The majority of farmers in the developing countries have family labor and
minimum hand tools for the limited available land area. Under these conditions,
growing a number of crops in mixtures may optimize the returns from the limited
resources available. In particular the sowing and harvesting dates of mixtures can
be adjusted to make better use of available labor than sole cropping (Yayock,
1979). Labor may be used more uniformly through the season under mixed
cropping (Aiyer, 1949; Baker and Norman, 1975; Lanini et al., 1991; Barik et al.,
1998).
10
2.1.5 WEED CONTROL
Less weed growth may occur under the canopy of mixtures because it
provides a more competitive community to plants, either for space and light than
sole cropping. This competition for available environmental resources results in
weed suppression and reduction in the amount of labor required for weeding (De
and Singh, 1979; Walton, 1983; Lanini et al., 1991; Akter et al., 2004).
Intercropping would be beneficial for weed control (Siner et al., 2000; Deksen et
al., 2002) to cover the ground, especially before the cassava canopy fully develops
(Zuofa et al., 1992; Olasantan et al., 1994). Such type of results was also
published by Agegnehu et al. (2008) in wheat-faba bean mixed cropping system.
2.1.6 COMPLEMENTARY EFFECTS
Component crops in mixture may complement each other nutritionally if
one crop requires substantial quantities of an element whilst the other crop has a
smaller requirement for this element. This will occur when the growth patterns of
crops in association differ in time so that the crops make their major demands on
resources at different times (Davies and Snaydon, 1973; Willey, 1979). Yield
improvement by mixed/intercropping as attributed mainly to the complementary
effects (Jensen, 1996), better resource use efficiency of the mixed cultures and the
buffering effects of the mixtures against diseases and weeds (Willey, 1979; Anil et
al., 1998). Hall (1974) and Prithiviraj et al. (2000) reported that there were some
complementary effects of nitrogen in grass/legume mixtures, which was attributed
to the nitrogen fixation by the legume component.
2.1.7 SOIL CONSERVATION
Appropriate mixtures may help to protect the soil from erosion, a major
cause of reduced soil fertility resulting from the removal of nutrients from the soil
surface (Hudson, 1957; Nelliat et al., 1974). Intercropping positively affected the
soil conservation by improving soil fertility (Jarenyama et al., 2000). Ardjasa et al.
(2000) reported that intercropping of cassava with upland rice and maize reduced
11
the soil erosion. Leihner et al. (1996) also observed that forage-legume intercrop-
ping controlled the soil erosion more effectively than mono cropping of cassava.
2.1.8 PREVENTION OF LODGING
Intercropping is helpful in prevention of lodging and thus allowing easier
mechanical harvesting (Osman and Osman, 1982; Droushiotis, 1989).
2.1.9 FINANCIAL STABILIZATION
Mixtures may stabilize returns over seasons as they provide more than one
commodity and can act as buffer against frequent price changes in one component
(Yayock, 1979; Francis, 1989). Rao et al. (1987) proved the profitable benefits of
intercropping over sole cropping due to the relative advantage of intercropping in
the sorghum-pigeon pea (40 to 70%), maize-groundnut (13 to 35%), and sorghum-
cowpea (18 to 25%) systems. Khola et al. (1999) noticed that intercropping of
maize+cowpea gave maximum net returns. Some intercropping systems are more
profitable than mono cropping (Pareek et al., 1991; Ghosh, 2002; Jamwal, 2002;
Iqbal, 2006; Ahmad, 2006). Intercropping of sorghum with soybean (Sherma et
al., 2000), with cowpea (Reda et al., 2005), and with mung bean (Rashid et al.,
2005) gave the additional financial benefits to the farmers. Goswami et al. (1999)
recorded the highest soybean equivalent yield and net return in an intercropping
system of soybean with sorghum and arhar. Khan et al. (2009) also reported such
type of results for wheat-canola intercropping system.
2.1.10 CONTROL ON DISEASES AND INSECT PEST
Mixtures may help to minimize the effects of diseases and insect pests
(Akter et al., 2004) if one component has repellent effects or if a component
serves as a trap crop (Risch, 1980; Szczukowski, 1989; Ramert et al., 2002). Finch
and Edmonds (1994) reported that intercropping of clover under sown was the best
technique to deter cabbage root fly, while Medicago litoralis to deter red carrot
root fly (Ramert, 1993; Ramert and Ekbom, 1996). Several green manure crops
were good traps for Lygus spp. in a lettuce agroecosystem (Ramert et al., 2001).
12
Mixed cropping is also an effective disease management tool in cereals. Vilich-
Meller (1992) stated that winter-rye/winter-wheat mixtures and spring-barley/oats
reduced fungal leaf diseases. Agegnehu et al. (2008) reported that the pressure of
chocolate spot disease was reduced when faba bean was sown in a mixed cropping
system with wheat.
2.1.11 TRANSFER OF NITROGEN FROM LEGUME TO NON-LEGU ME
Atmospheric fixed-N by legumes is transferred and taken up by the non-
legume grown in mixture with the legume. Lal et al. (1978) reported that cowpea
benefited the wheat by providing about 40 kg N ha-1. Similarly, Bouldin et al.
(1979) reported the contribution of legumes regarding proving nitrogen to non
legumes in the mixture. Similarly, Danso et al. (1987) also evaluated the effect of
different sown densities of barley-faba bean on the amount of N fixation by faba
beans and fixed N transferred from the legume to barley. They reported that dry
matter yield and total N of faba beans intercropped with barley was reduced
compared with the sole crop. However, the proportion of the N in faba beans that
was derived from fixation was significantly increased in the intercropped system.
Fujita et al. (1992) reported the transfer of nitrogen from legume to associated
cereal and ultimately it increases the yield and efficiency of N use of the cropping
system. Furthermore, the distance between the roots of cereal/legume is very
important because nitrogen is transferred through the intermingling of roots. Crops
might be mixed in different ratios and an ideal planting ratio of mixture may
produce higher gross returns. In mixtures, increase in yield was due to the
improved nitrogen of the cereal (Connolly et al., 2001). Studies have shown that
competition between cereal/legume for N may improve nitrogen fixation activity
in legumes (Fujita et al. 1990a; Hardarson and Atkins, 2003). Different
researchers have also stated the transfer of fixed nitrogen to the non-legumes sown
in combination (Giller et al., 1991; Stern, 1993; Elgersma et al., 2000; Chu et al.,
2004). Searle et al. (1981) there is found no evidence of direct transfer of nitrogen
13
from legume to the cereal sown in association and nitrogen fixation reduced due to
competition between intercrops. Similarly, Izaurralde (1992) found no evidence of
transfer of nitrogen from field pea to barley. However, the proportion of nitrogen
derived by pea intercrops was 39% higher than that derived by the sole pea. Jensen
(1996) also studied the effect of intercropping of pea-barley on nitrogen fixation
and transfer of N from legume to barley. He reported that there was no evidence of
transfer of nitrogen from pea to barley. Furthermore, he stated that the advantages
of pea-barley intercropping system were mainly due to the complementary use of
inorganic and atmospheric nitrogen by the associated crops, resulting in reduced
competition for inorganic N, rather than a facilitative effect, in which
symbiotically fixed N2 is made available to barley.
2.1.12 YIELD AND YIELD COMPONENTS
Higher yields from mixtures (Jensen, 1996; Anil et al., 1998; Dapaah et al.,
2003; Chen et al., 2004; Iqbal, 2006) have been attributed to more efficient
utilization of light by their canopies (caused by differences in height and leaves of
the component crops in mixture), efficient use of soil resources due to differences
in rooting depth and rooting patterns, the peak growth demand of the component
crops occurring at different times and one crop may provide physical support for
another or may provide shelter for another (Papastylianou, 1990; Lanini et al.,
1991; Hikam et al., 1992). Sharma and Gupta (2001) stated that the combination
of pearl millet + cluster bean produced significantly highest LER (1.21) than the
intercropping of pearl millet with cowpea. Similarly, Abou-Hussein et al. (2005)
reported the maximum LER and net return from the intercropping system of green
bean as main crop with head lettuce and/or green onion. Ennin et al. (2001) also
reported that the intercropping system gave the higher LER values in comparison
to sole crops. In a similar way, Roy et al. (1990) intercropped roselle with
blackgram, cowpea, soybean, groundnut and sesame under three row planting
patterns at three different sowing dates and reported that the LER was increased in
14
the intercropping systems. Cordero and McCollum (1979) conducted an
experiment on maize sown alone and intercropped with soybeans, snap beans, or
sweet potatoes. They found the highest LER for the intercropping system than the
sole cropping. Sivakumar and Virmani (1980) grew maize and pigeon pea in sole
and intercropping system to compare growth and interception of
photosynthetically active radiation (PAR). They observed the highest efficiency of
dry matter production and cumulative intercepted PAR for maize/pigeon pea
intercrop, followed by sole maize and sole pigeon-pea. However, the growth and
yield of maize crop were non-significant in both pure and even in intercropping.
Similarly, Awal et al. (2006) concluded that a maize/peanut intercropping system
would help to increase production through the efficient utilization of solar energy.
They reported that the mean radiation use efficiency of intercropped peanut was
79% higher than that of peanut sown alone. The radiation use efficiency of
combined intercropped stands was more than two-fold that of sole peanut, but
slightly lower than that of maize alone. Willey et al. (1983) also concluded that
legume and non-legume intercropping systems gave higher yields than
monoculture by using environmental resources more fully over time or more
efficiently in space. Furthermore, the maize-groundnut intercropping system
proved to be the best. Rao et al. (1983) reported that the sorghum/pigeon pea
intercropping system produced higher grain and dry matter yields than sole crops
when it was not fertilized or fertilized with 80 kg N ha-1. The yield of pigeon pea
in intercropping was about 50% less than yield of sole pigeon pea. Similarly,
Bhatnagar and Chaplot (1991) reported that intercropping of maize with green
bean gave higher maize equivalent yields and LER than maize sown alone.
According to Adeniyan and Ayoola (2006) and Muoneke et al. (2007) LER of the
intercropping system was higher than mono cropping. Highest maize grain and
fodder yields, LER and net returns from intercropping of maize with Vigna
radiata have also been obtained by Ali, (1993). In a similar way, Hussain et al.
(1999) also reported that sorghum intercropped with cluster bean or cowpeas gave
15
the highest fresh and dry matter yield of sorghum when two rows strips of
sorghum were intercropped with 3 rows of cluster bean. Kamanga et al. (1999)
grew maize alone and intercropped with sesbania (Sesbania sesban), Tephrosia
(Tephrosia vogelii) and pigeon peas (Cajanus cajan). The legumes were relay
intercropped at first weeding using seedlings for sesbania and seeds for Tephrosia
and pigeon peas. The intercropping with sesbania produced the highest maize
yields (2937 kg ha-1) followed by Tephrosia (2592 kg ha-1) and then pigeon peas
(2122 kg ha-1). Similarly, Khola et al. (1999) intercropped maize with cowpea,
black gram, soybean and also planted their sole stands on early (10 June), normal
(25 June) and late (10 July) sowing dates. The intercropping of maize with cowpea
and black gram gave higher maize-equivalent yields (35.28 and 30.50 q ha-1),
respectively than sole maize (28.00 q ha-1). Khan et al. (2001) sowed cluster bean
at 30, 45, 60 and 75 cm spaced single, double, triple and four row strips,
respectively. They reported that cluster bean at 45cm spaced double-row strips
with two rows of mungbean produced significantly more branches, grain and stalk
yield ha-1 while number of branches and stalk yield of mungbean were not
affected. It was also observed that LER in intercropping of cluster bean planted at
45cm spaced double-row strips with two rows of mungbean was highest (1.55).
Chirwa et al. (2003) evaluated the productivity of maize, pigeon pea and gliricidia
grown as sole stands or in mixed cropping systems. The mixed cropping systems
were most productive. There was no beneficial influence of pigeon pea on
performance of maize, either in the presence or absence of gliricidia. They
suggested that agroforestry systems containing gliricidia might be used to replace
traditional maize + pigeon pea systems in southern Malawi. Rashid et al. (2005)
concluded that sorghum intercropped with mungbean or cluster bean gave the
higher grain yield than sole cropping. Tsubo et al. (2003) also reported that the
advantages of a maize-bean intercropping system on total LER for yield and
growth ranged between 1.06 to 1.58 and 1.38 to 1.86, respectively. Singh and
Balyan (2000) concluded that intercropping of sorghum + cluster bean increased
16
the total productivity and net returns over sorghum sown alone. Pal and Shehu
(2001) also investigated the beneficial effects of legumes to yield and nitrogen
uptake of maize. They reported that all legumes contributed to yield of maize
either intercropped or grown after legume as a sole crop. Ahmad et al. (2006)
planted sorghum sole and as an intercrop with different legumes, (i.e., mungbean,
cluster bean, cowpea and sesbania) to compare their competitive performance. The
cowpea proved to be the more competitive crop than the other legume intercrops
and an increase in mixed yield of 88% was noted over the sole sorghum. Similarly,
Iqbal et al. (2006a) grew maize in association with different forage legumes
namely, cluster bean, rice bean, and cowpea under different sowing techniques.
The maize+cowpea association produced the highest forage yield when cowpea
was intercropped in alternative rows. However, Santalla et al. (1999) reported that
intercropping of bush bean with maize did not make better use of land than
conventional sole cropping under their environmental conditions.
Sowing of legumes in intercropping systems may increase/decrease the
growth, yield and yield attributes of cereal in association. Bandyopadhyay and De
(1986) reported that intercropping with legumes increased the dry matter
production and leaf area index of sorghum. The highest plant height and LAI of
maize sown in association with legumes (soybeans, cowpeas, french beans and urd
beans) was also reported by Ranbir et al. (2001). Wanapat et al. (2005) reported
that intercropping of cassava with legumes (cowpea and Phaseolus calcarlatus)
increased the foliage yield of cassava. The highest intercepted PAR and dry matter
production of the intercrops in comparison to single crops was noted by Ennin et
al. (2002). Matiullah et al. (2005) stated that the grain yield of wheat was
increased, when it was intercropped with chickpea at 1:1 ratio as compared to sole
wheat. Similarly, Gill et al. (2009) conducted a pot experiment to evaluate the
effect of mixed cropping (wheat+chickpea) on growth and nodulation of chickpea.
They reported that maximum biomass yield of wheat was due to the associated
crop. However, Ghuman and Lal (1991) reported the reduction in plant height and
17
leaf area index of maize by intercropping as compared to mono crops. However,
the intercropping of maize, melon and yam produced 61% and 98% more food
than mono crops. Similarly, Chui and Shibles (1984) observed that soybean yield
in intercropping was reduced 87% in comparison to mono cropping. They further
concluded that intercropping delayed the tasseling and silking of maize up to two
days. Malik et al. (1998) also reported that intercropping reduced the yield of
fellow crops but total yield and net return was higher than sole cropping.
Jorgensen (1991) found that intercropping of maize and faba bean decreased the
maize grain yield, DM yield and total stand yield while N uptake in intercropping
was more than maize sown in monoculture. Fininsa (1997) also reported the
reduction in grain yield of bean and maize by intercropping up to 67% and 24%,
respectively, while, the land equivalent ratio was superior to sole cropping.
Prithiviraj et al. (2000) intercropped corn with soybean and lupin for silage to
investigate the effects of seeding date and number of rows of large seeded legumes
planted between the corn rows. The silage yield was decreased by the seeding of
corn and large seeded legumes. Kawamoto et al. (1983) reported that sorghum
DM yield was not increased by soybean mixed cropping, however the relative
total yield of mixture was more than one. No competition was observed between
the crops sown in mixture. Tembakazi and Lucas (2002) also investigated the
effect of maize, beans and pumpkin intercropping on yield. They concluded that
intercropping adversely affected the plant height and other parameters of the
component crops. The yield of individual crop in each intercrop was reduced by
intercropping up to 15% and 13% for maize and beans, respectively in comparison
their sole crops, but the land equivalent ratio of intercropping with maize was
highest in comparison to sole cropping. Egan and Ransom (1996) reported sowing
cereals into young alfalfa resulted in grain yield reductions of 6 to 62% in
comparison with cereal alone. Humphries et al. (2004) also reported similar grain
yield reduction of 13 to 63% in wheat sown with alfalfa than sole wheat. Zewdu
and Asregid (2001) also noted the reduction in forage yield in intercropping
18
system of maize and legumes in comparison to sole crops. Ghosh (2002) also
conducted a field trial on groundnut intercropping with three cereal fodders,
maize, pearl millet and sorghum to assess the profitability of intercropping system
over sole cropping of groundnut. He concluded that the green fodder yield was the
highest in pearl millet with 2 cuts. The highest pod yield (24 q ha-1) was recorded
in sole groundnut while, significant reduction in yield, yield attributes and leaf
area, nodule mass of groundnut as recorded when 2 cuts of pearl millet and
sorghum were planned. However, such yield reduction was nullified by high
fodder yield and high net returns obtained from 2 cuts of pearl millet. Similarly,
Dapaah et al. (2003) also intercropped cassava, maize, soybean and cowpea to
determine the yield, land use efficiency and yield stability of intercropping
systems. Intercropping significantly reduced the grain or tuber yield of maize,
cassava, gblemoduade and cassava, Ankra by 23-70%, 16-49% and 24-64%,
respectively. Maize yield decreased with increased number of soybean rows.
However cowpea yield was higher when intercropped with Ankra than with
Gblemoduade. The intercrops had more LER (1.27-2.83) and were more stable
than mono cropping. According to Clement et al. (1992) intercropping reduced the
yield of soybean (22 and 23% in two seasons) and maize (39 and 18% in two
seasons) compared to their relevant sole crops. Accordingly, Rashid and
Himayatullah (2003) evaluated the feasibility of legumes intercropped with
sorghum. Intercropping of legumes significantly reduced the plant height and
grain yield of sorghum. Similarly leaf area index of intercropped sorghum was
lower than the LAI of sorghum sown alone and the reduction was more
pronounced when the associated crop was cluster bean. Lauriault and Kirksey
(2004) also reported that intercropping of pea or vetch reduced the yield of wheat
and triticale compared to their sole crops. Furthermore, they concluded that quality
of wheat or triticale was improved when intercropped with pea. Hauggaard et al.
(2003) reported that pea-barley intercrop gave lower yield than sole pea but it was
greater than sole barley. The LER showed that resources utilized by the intercrop
19
were 17% to 31% more than by the sole crops. Dung et al. (2005) also reported a
reduction of cassava yield when it was intercropped with flemingia, but in the 2nd
year, it increased. The CP yield was increased when cassava foliage was
intercropped with flemingia. Kondo et al. (2006) reported that the dry matter yield
of maize/sesbania bi-crop was lower than maize mono crop when they were sown
in an intercropping system. Further, they recommended that the sesbania may be
intercropped with early maturing maize for forage because it has the same growing
season, high growth rate and DM yield. Similarly, Adetunji (2008) concluded that
intercropping depressed the performance of sorghum more than sunflower. The
sorghum plants grown in alternate hills in association with sunflower produced
shorter stems, less dry matter and seed yields. The highest dry matter and seed
yields were observed when sorghum was planted in five alternating rows with
sunflower.
Mixed cropping, especially with legumes provides a more nutritionally
balanced diet to the farmer’s family and quality of yield is improved (Francis and
Sanders, 1978; Szczukowski, 1989; Prithiviraj et al., 2000; Reda et al., 2005;
Ayub et al., 2004; Ibrahim et al., 2006). Cereals provide the carbohydrate and
legumes provide the protein requirements. Mpairwe et al. (2003) reported that
maize-lablab stover or oats-vetch hay were best basal diets to get optimum milk
production from crossbred cows. Ofosubuda et al. (1995) found that total N
accumulation by sorghum in association with soybean was higher than for mono
crop. Similarly, Khushawaha and Chandel (1997) reported the maximum protein
yield of sorghum in soybean + sorghum system than in sole sorghum. Andrighetto
et al. (2008) evaluated the effect of intercropping on the quanti-qualitative silage
production of maize-soybean system and reported that intercropping significantly
improved the protein contents.
Mixed/intercropping of legumes with cereals improve the quality of the
products (Kondo et al., 2006). Waligorska (1982) reported that the protein content
and total protein yields were higher for a maize-bean mixture than for maize sown
alone. Maasdorp and Titterton (1997) studied the intercropping of fifteen legumes
with maize for nutritional value of maize silage. Legumes were also sown as sole
crops. Biomass yield with good digestibility and CP contents were greater in sole
crops of soybean, forage soybean and lablab. Finally, they recommended at
soybeans, lablab, velvet bean and possibly sun hemp and cowpea be intercropped
with maize. According to Krishna et al. (1998) the highest crude protein
percentage was obtained in comparison to maize sown as sole crop. The green and
dry forage yields were also highest when maize+cowpea mixture was sown in
rows 30 cm apart. However, Pandey et al. (1998) stated that total (maize +
legume) green fodder and crude protein yields were not significantly affected by
intercropping of maize with cowpea, rice bean and horse gram. However, a maize
+ rice bean intercropping system gave highest dry matter yield (7.50 t ha-1).
Carruthers et al. (2000) also recorded improved quality of silages when legume
was intercropped with cereal forages. Furthermore, intercropped crops received 90
kg ha-1 less nitrogen than mono crop (180 kg ha-1). A field experiment was
conducted by Redfearn et al. (1999) to evaluate the effect of intercropping of
soybean with sorghum on forage quality. The leaf CP of mono cropped soybean
was more (25 g kg-1) than intercropped soybean, however, CP of stem from
intercropped soybean was more (12 g kg-1) than sole soybean. Carr et al. (2004)
concluded that CP concentration of oat forage was lower than barley when these
were intercropped with pea. ADF and NDF concentration (39 and 41 g kg-1) were
lower, respectively for barley compared to oat. Eskandari et al. (2009) investigated
the effect of intercropping on light interception, nutrient uptake and forage quality
of cowpea. They reported that intercropping decreased the crude protein contents
of cowpea in comparison to sown alone, however, it improved the PAR
interception and nutrient uptake of cowpea.
21
2.2 EFFECT OF COMPONENT SEED RATIO / PLANT DENSITY
Seed ratio/plant density is one of the most important management factors
which can be used to improve the yield and quality of crops. The overall mixture
density and the relative proportions of component crops are important in finding
the yield and production efficiency of cereal-legume mixtures (Lakhani, 1976).
According to Dahlmann and von Fragstein (2006) yield and quality of intercrops
may be influenced by seed rate, techniques and nitrogen supply.
2.2.1 Growth, yield and yield attributes of the component crops
Fisher (1977) compared maize-bean mixtures with pure stands of two crops
at three plant densities and concluded that maximum yield advantage was only due
to the increased population level in the mixtures. Moursi et al. (1980) examined
the effect of intercropping of cowpea with sorghum on forage yield and reported
that fresh and dry weight of forage, protein content and solar conversion efficiency
of sorghum increased with increasing density of intercropped cowpea. Highest
forage yield was obtained when cowpea was intercropped with sorghum at 15cm
spacing. Thomas et al. (1984) grew three sorghum cultivars in pure stands at a
seed rate of 50 kg ha-1 or in mixture of sorghum + cowpea by using a seed rate of
45+5, 40+10, 35+15 or 30+20 kg ha-1 and they observed that increasing the
proportion of cowpea in the mixture improved the fresh fodder yield, ash and
protein contents but decreased dry matter content. Hefni et al. (1984) reported that
maize plant height increased with decreasing plant density with component
soybean. The number of leaves plant-1 and leaf area plant-1 of both maize and
soybean increased with decreasing plant density. Stem diameter at the second
internode of maize increased with decreasing plant density.
Gardiner and Craker (1981) reported that growth and yield of the legume
component is reduced markedly when intercropped with high densities of a
component. In a maize-bean intercrop system, increasing the maize density three
fold, from 18,000 to 55,000 plants ha-1 caused a reduction of 24% in the leaf area
and 70% in the yield of associated beans. Similarly, when intercrop sorghum
22
densities were varied from 55,000 to 2,20,000 plant ha-1, the intercrop sorghum
yield response was linear. In contrast, intercrop pigeon pea yield decreased with
rising sorghum density (Freyman and Venkateswarlu, 1977). The DM of maize
was also decreased with increasing plant population of bean in the intercropping
system used by Morgado and Willey (2003). Ali and Raut (1985) intercropped
sorghum and pigeon pea at different plant populations (67% + 33%, 100% +100%,
100% + 50% and 50% + 100% on the basis of pure stands) against the sorghum
and pigeon pea sown in pure stands by using the plant population of 2,22,000 and
1,11,000 plants ha-1, respectively. They observed non-significant difference of
sorghum DM accumulation in intercropping or sown as a sole crop but reduction
in the DM accumulation of pigeon pea in intercropping was noted. Pawar et al.
(1985) obtained highest grain (3.34 t ha-1) and fodder (4.75 t ha-1) yields of
sorghum when sown in skipped row pattern with 45 or 90cm between rows with or
without intercropping of chickpea sown at 33 or 66% normal density in rows 45cm
apart. Pookpakdi and Sriwatanapongse (1985) had sown sweet corn and soybeans
as sole and intercrop in combinations of 75% + 25%, 50% + 50% and 25% + 75%.
The soybean yields ranged from 0.38t to 1.39t ha-1 for 75%+25% and sole crop,
respectively. The 25% + 75% mixture proved to be the most favourable
intercropping combination. However, the combination of 50% + 50% gave the
highest LER and it was superior to mono crops. Araujo et al. (1986) reported that
both maize and bean gave higher yields when they were planted as mono crops.
However, a reduction in the yield of maize was noted, when beans were
intercropped at 200000 plants ha-1. Reddy et al. (1986) observed that when
sorghum at seed rate of 20 kg ha-1 was sown with cowpea at 0, 25, 50, 75 and
100% of sorghum seeding rate, the respective DM yields of forage were 16.5,
16.8, 17.0, 18.5 and 19.2 t ha-1. Digestible crude protein in the forage was 1.85,
2.48, 2.97, 3.35 and 3.97%, respectively and all were significantly different from
one another. Bryan and Materu (1987) intercropped maize at 40400 or 50500
plants with green bean at 0, 20,200, 40,400 or 80,800 plants ha-1. The dry matter
23
yield of maize increased from 9.5 to 10.6 t ha-1 with increasing plant population.
However, the yield of green bean was not affected by plant population.
Furthermore, intercropping with cowpeas increased the total CP yield by 15%
compared with maize alone. Accordingly, Craufurd et al. (2000) intercropped
sorghum-cowpea and/or millet-cowpea in alternate rows at various densities from
20000 to 80000 plants ha-1 to examine the effect of plant density on yield. With
the increase in cereal plant density, the yield of cowpea was decreased, whereas
cereal and total intercrop yield was increased with increasing plant density.
Biomass yield of all intercrops was also increased with increasing density in a
similar manner. Similarly, Madhavan et al. (2008) studied the effect of different
plant densities and intercropping of sorghum cv. CO 22 on compatibility of pigeon
pea genotypes. They recorded that increase in the plant density significantly
increased the dry matter yield, LAI and CGR at early stages, whether NAR, RGR
and CCR was reduced at final growth stage. Intercropping also significantly
reduced the dry matter production LAI, CGR, NAR and RGR. Hiremath et al.
(1987) grew sorghum and pigeon pea either as sole crops or intercropped in
different row ratios (i.e. 4:1, 4:2, 2:4 and 1:4). They concluded that yield of each
crop was reduced with decrease in number of its intercropped rows. Finally they
reported that 4:2 row ratio of sorghum and pigeon pea combination gave the
highest gross return. Hong et al. (1987) grew maize and soybean as single crops or
intercropped in maize : soybean row ratio of 1:1, 1:2 or 1:3. The stem length,
diameter, number of branches and nodes of soybean did not differ significantly
between sowing arrangements. Furthermore, the stalk diameter of maize was
highest in 1:3 row ratio against the lowest height in 1:2 row ratio. Highest, total
intercrop DM yield was recorded in 1:1 row ratio. Malinovskil and Shnurnikova
(1987) concluded that sowing of sorghum and soybean in a 1:1 and 2:1 row ratio
increased the fodder nutritive value (107-105g CP/FU) compared with sorghum in
pure stands (65g CP). Toniolo et al. (1987) compared maize alone and maize-
soybean strip intercropping sown at ratios 1:1 to 5:1. They reported that maize
24
sown alone gave the highest dry matter yield than in intercropping. However, the
CP yields were greater in intercropping. Further they declared that 1:1
intercropping ratio gave higher LER value and prove better exploitation of
cultivated area than sole cropping. Babu et al. (1988) intercropped sorghum with
black gram or green gram in 2:2, 2:4 or 1:4 row ratios to evaluate its best row ratio
combination with legume and they reported that sorghum and mungbean mixture
in 1:4 ratio gave the highest sorghum grain equivalent yield of 5.25 t ha-1 than 4.46
t ha-1 for sorghum sown in pure stands and increased land equivalent ratio to 1.14.
Drousiotis (1989) grew oats and triticale and two legumes (i.e. vetch and peas) as
sole and in mixtures at various seed ratios (20:80, 40:60, 60:40 and 80:20). He
concluded that cereal sole crops produced highest (8.40 t ha-1) dry matter and
digestible organic matter (4.12 t ha-1) than the legume mono crops, 3.68 and 2.18 t
ha-1, respectively. Furthermore, total dry matter production decreased linearly as
the seed ratio of legume component increased in the mixture. He also recorded the
maximum digestibility and CP content in the mixtures of triticale and peas. Gupta
(1990) reported that sorghum grain and fodder yields were not significantly
affected by the intercropping with different legumes. He recorded the highest
legume seed yields (0.75-1.04t ha-1) in pure stands rather than in intercropping
(0.08-0.46 t ha-1). Oliveira and Garcia (1990) planted grain sorghum cv. BR-300
and forage sorghum cv.BR-601 and CMS-XS-649 alone at 30 seeds m-1 or
intercropped with soybean cv. UFV-5 at 30 or 60 seeds m-1 row length between
the sorghum rows. They found that sorghum DM production was not significantly
affected by intercropping with soybean but was affected by the cultivar. However,
DM production of soybean was significantly affected by both sowing density and
sorghum cultivars. Total dry matter production of sorghum in intercrops was more
with decreasing proportion of soybean in the forage mixture. The forage crude
protein content of sorghum was increased by the presence of soybean in the
mixture. Evangelista et al. (1991) grew maize with four or six plants m-1 of row in
pure stands or intercropped with soybean at 25 or 50 plants m-1 of row. They
25
reported that DM contents were greater in pure maize (34.3%) than in all other
treatments (31.0-33.8%). Forage crude protein contents (7.90-9.00%) were greater
in intercropping than sown in pure stand. Hikam et al. (1992) compared the early
and late maturing maize hybrids in intercropping with Psophocarpus
tetragonolobus cv. Tpt-1 at plant densities of 35900 and 46500 plants ha-1 in 1984
and 47500 plants ha-1 in 1985. The intercropping of Psophocarpus tetragonolobus
with early maize produced 14% and 18% more biomass than pure early maturing
maize during 1984 and 1985, respectively. Finally they suggested that sowing of
maize with Psophocarpus tetragonolobus is the best intercropping system to
provide higher biomass and protein contents of silage. Similarly, Lima Filho
(2000) compared the productivity of maize and cowpea as sole crops at a
population of 40,000 plants ha-1, and as an intercrop at a population of 20,000
plants ha-1. The maize productivity increased 18% in relation to sole crop,
whereas, 5% decrease was observed with cowpea. Hennawy and Bially (1997)
intercropped mungbeans with sorghum in four different seeding ratios and
reported that 2:1 mungbean : sorghum ratio gave the highest mung bean yield than
other arrangements. Renganayaki and Subramanian (1992) grew sorghum cv. Co
26 and 6 pigeon pea cultivars in pure stands or intercropped in 2:1 or 3:1 row
ratios. They reported the highest yield from cv. CoRG 11 in 3:1 row ratio of
sorghum:pigeon pea. Mohammed et al. (2008) intercropped six cowpea genotypes
with local millet under 1:1, 1:2, 2:2 and 2:4 row arrangements. Genotype and row
arrangement did not affect the yield, yield attributes and partial LER of millet.
However, panicle weight m-2 of millet was significantly lower at 1:1 and 2:2 than
1:2 and 2:4 row arrangements in the 2nd year. Furthermore, intercropping reduced
grain yield of cowpea by 47%. However, the total LER and gross monetary return
were higher at 2:4 row arrangements relative to the other arrangements.
Hazra et al. (1993) evaluated the yield and yield components by growing
pearl millet in single and paired rows with and without 1 or 2 rows of cowpeas,
cluster bean or rice bean. The legume yield compensated for the loss of millet
26
yield in the intercropped systems by increasing total green forage yield, 11-29%
and dry forage yield by 5-23% over sole pearl millet. Similarly, Chittapur et al.
(1994) intercropped maize cv. Deccan 103 with six forage legumes, cowpeas,
horsegram, lablab, black soybean, sunhemp and soybean in 2:1 row ratios. All
crops were also sown as sole. The legumes did not adversely affect the plant
height, total DM production or grain yield of maize. The maize yields were
significantly higher in intercropping system than the sole crop due to moisture
conservation by the intercrops. However, Griesh and Yakout (2001) evaluated the
effect of three plant population densities of maize (i.e. 175000, 21000 and 28000
plants per feddan) under three N levels, (i.e. 60, 90, 120 Kg fed-1). They reported
that increased plant densities significantly decreased all yield traits and yield
components except ear position. Similarly, Ayub et al. (2004) reported that the
plant height, number of leaves of both sorghum and rice bean were significantly
affected by seed proportions of sorghum and rice bean under mixed cropping
system. The green forage yield and dry matter yield of sorghum in mixture was
also higher than when sown alone. Increased seed rate of rice bean in mixture
increased crude protein contents. They concluded that yield and quality of fodder
was equally good, when crops were sown at seed proportions of 50: 50, and 35:65.
In the same way, Ibrahim et al. (2006) studied the effect of seed ratio of maize-
cowpea mixed cropping on forage yield and quality. The maximum green fodder
yield (68.30 t ha-1) at a maize-cowpea seed ratio of 75:25 against the minimum
(22.60 t ha-1) was recorded when cowpea was sown alone. Crude protein, dry
matter and ash contents were also influenced significantly by different seed ratios.
The concentration of ash and crude protein increased with increased cowpea
population, whereas dry matter contents were decreased by increased population
of cowpea in the mixture. Similarly, Dahmardeh et al. (2009) evaluated the effect
of different planting ratio (100:100, 50:100, 100:50, 25:75, 75:25, 50:50, 0:100
and 100:0) of maize and cowpea on economical and biological yield and quality of
maize forage. They reported the maximum green forage yield at highest sowing
27
density 100%:100% maize:cowpea. However the highest CP content was observed
in sole cowpea while the minimum were recorded in the plot of maize sown alone.
2.2.2 Mixed yield, land equivalent ratio and quality traits
Moursi et al. (1980) reported that green, dry matter yield and protein content
of sorghum increased with increasing seeding density of cowpea in intercropping.
Similarly, Thomas et al. (1984) noted that increasing proportion of cowpea in the
mixture improved the fresh fodder yield, ash and protein contents of the cereals.
Park et al. (2002) sowed maize and bean both in monoculture and intercropped at a
range of densities. The maize yield was not affected, but the yield of bean was
reduced by intercropping. The highest LER was also observed in the intercropping
system at high maize densities. Khandaker (1994) examined the effect of different
seed proportions of maize and cowpea (100% maize, 75% maize + 25% cowpea,
50% maize + 50% cowpea, 25% maize + 75% cowpea, and100% cowpea) on forage
yield and quality. He recorded the highest and lowest green forage yield at seed
proportion of 75% maize + 25% cowpea and cowpea alone at 100%, respectively.
The crude protein contents of forage mixture increased with increasing proportion of
cowpea. Crude fibre and ash contents did not differ significantly among treatments.
He recommended that maize and cowpea mixture sown at 75%:25% seed ratio is a
good technique to improve the forage yield and quality. Parveen et al. (2001) also
studied the effect of five seed ratios of rice bean and blue panic on forage yield,
yield contributing parameters and crude protein contents. They concluded that the
mixture of 75% rice bean and 25% blue panic produced the highest DM yield and
CP content of rice bean were higher at 100% seed ratio and decreased with the
increase in grass ratio. Similarly, Azim et al. (2000) investigated the effect of maize
and cowpea intercropping on biomass production and silage characteristics. Maize
was sown alone and intercropped with cowpea at seed ratio of 85:15 and 70:30. The
data revealed a significant increase in biomass and crude protein production of
fodder in which maize and cowpea were intercropped at seed ratio of 70:30
followed by a seed ratio of 85:15, compared with maize alone. However, no
28
difference was observed in the production of total digestible nutrients among the
treatments. The data further indicated that intercropping of maize and cowpea at a
seed ratio of 70:30 also produced better quality silage. Finally they stated that yield
and quality of forage may be enhanced by intercropping of oat or barley with pea.
According to Mudita et al. (2008) intercropping of maize and soybean at 5:2 row
ratio proved to be more efficient than sole cropping with regard to LER and income.
Chellaiah and Ernest (1994) grew sorghum cv. CO 25, maize cv. African Tall,
cowpea cv. CO-3 and soybean cv. CO-1 as mono crops and in mixture of 1:1 or 2:1
row ratios. The fresh yields were 51.8, 39.1, 14.3 and 19.9 t ha-1 for sole crops,
respectively. Sorghum grown with soybean in 2:1 mixture yielded 60.7 and 1.55 t
ha-1 fresh forage and crude protein, respectively, while maize grown in mixture with
soybean in 2:1 row ratio gave 43.2 and 1.16 t ha-1 fresh forage and crude protein
yield, respectively. Similarly, Bulson et al. (1997) intercropped wheat and faba
beans in an organic farming system as sole crops and additive intercrops. They were
sown sole crops at 25, 50, 75, 100 and 150% of the recommended density and the
intercrops consisted of all density combinations of wheat and beans from 25 to
100%. The grain yield of sole wheat and bean increased significantly as their
density was increased and highest yield of both crops was recorded at 100% seeding
density. The highest LER (1·29) was observed when wheat and beans were both
sown at 75% recommended density. The increase in beans density increased the
nitrogen content of wheat grain and whole plant biomass; significant increase in
grain protein at harvest was also noted. Total accumulated N by the wheat decreased
with increasing bean density and it was due to a reduction in the wheat biomass. It
was also observed that all of the intercrops accumulated more N than the sole wheat,
however, it was lower than sole beans. Carr et al. (1998) intercropped barley and oat
@ 93, 185 and 278 kernels with pea using seed rate of 40, 80 and 120 seeds m-2 to
evaluate cereal-pea intercropping system for forage production, CP and N yield.
They also grew two cultivars of barley and two of oat as sole crop @ 185 seeds m-2.
The forage yield was not affected by intercropping when the cereal crop was sown
29
at the sole or greater seed rate but it was reduced by intercropping when cereal was
sown at half of the sole seed rate. The CP concentration was increased with
increasing seed rates of pea. The cereal component contributes more to yield than
pea but the CP concentration of forage can be increased as the relative proportion of
pea is increased. Mishra et al. (1997) reported that the sorghum intercropped with
cowpea sown in paired alternate rows (2:2) produced the maximum green forage,
dry matter and crude protein yields in comparison to intercropping with horse gram.
Moga et al. (1994) grew two maize cultivars at 40,000-100,000 plants ha-1 with
soybean at 0-200,000 plants ha-1 and they recorded the highest yield by maize sown
at 100,000 plants + soybean at 50,000 plants with cv. fundulea-102 and with maize
at 66,000 plants + soybean at 200,000 plants or at 100,000 plants + soybean at
100,000 plants with Elan. Protein yield of both maize cultivars was increased with
the increase in soybean plant population. Blumenthal et al. (2003) also estimated the
influence of plant population and N application on corn yield in semi arid western
Nebraska. Five plant populations (17,300, 27,200, 37,100, 46,900, and 56,800 plants
ha-1) and five N fertilizer rates (0, 34, 67, 101, and 134 kg N ha-1) were tested.
Overall, grain yield increased (353 kg ha-1) with increasing population from 17,300
to 27,200 plants ha-1.
Sharaiha (1994) stated that intercropping of maize with green bean in row
ratio of 1:1, 1:2, 2:1 or 2:2 gave lower combined yield than the sole crop. Pandey
et al. (2002) conducted an experiment to find out the optimum level of three plant
population (i.e. 1,11,000, 1,