Soil & Tillage Research 110 (2010) 101–107

Tillage and herbicides impact on weed control and wheat yield under rice–wheatcropping system in Northwestern Pakistan

Khalid Usman a,*, Shad Khan Khalil b, Amir Zaman Khan b, Iftikhar Hussain Khalil c,Muhammad Azim Khan d,1, Amanullah b

a Department of Agronomy, Faculty of Agriculture, Gomal University, Dera Ismail Khan, KPK, Pakistanb Department of Agronomy, Faculty of Crop Production Sciences, KPK Agricultural University, Peshawar 25130, Pakistanc Department of Plant breeding and Genetics, Faculty of Crop Production Sciences, KPK Agricultural University, Peshawar 25130, Pakistand Department of Weed Science, KPK Agricultural University Peshawar 25130, Pakistan

A R T I C L E I N F O

Article history:

Received 19 January 2010

Received in revised form 30 June 2010

Accepted 4 July 2010

Keywords:

Tillage

Herbicides

WCE

Grain yield

BCR

Wheat

A B S T R A C T

Wheat (Triticum aestivum L.) production is low in rice (Oryza sativa L.)–wheat cropping system in the

low-precipitation zone of Dera Ismail Khan, Pakistan. A 2 years field experiment was conducted during

2007–2009 to evaluate the effect of tillage systems and herbicides on weed control efficiency (WCE) and

wheat yield under rice–wheat cropping system. Three tillage systems, zero tillage (ZT), reduced tillage

(RT) and conventional tillage (CT) and five herbicide treatments viz. 2,4-D, Puma super, 2,4-D + Puma

super at 1.25 L ha�1 each, Affinity at 2 kg ha�1 and weedy check were evaluated in randomized complete

block design with split plot arrangement replicated four times. Tillage treatments significantly affected

grain yield, net benefit (NB), and benefit cost ratio (BCR), while no significant effect on weed control

efficiency. Both RT and ZT produced higher grain yield (5583.8, 5575.1 kg ha�1), while maximum NB (US

$ 1196.0 ha�1) and maximum BCR (5.5) were observed in ZT. Grain yield, NB and BCR were the lowest in

CT. Maximum weed control efficiency (WCE) (94.1%), grain yield (6906.9 kg ha�1), NB (US $ 1522.2 ha�1)

and BCR (6.25) were recorded with Affinity, while minimum grain yield (3765.9 kg ha�1), NB (US $

710.9 ha�1) and BCR (3.6) were recorded in weedy check. Maximum WCE (91.4%) was recorded with

Affinity and 2,4-D + puma super, irrespective of the tillage intensity. Affinity in combination with ZT was

more productive and economical than RT and CT.

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1. Introduction

Rice (Oryza sativa L.)–wheat (Triticum aestivum L.) croppingsystem (RWCS) occupies about 24 million ha in the Asiansubtropics (Ladha et al., 2000) and is a major production practicein low-precipitation zone of Dera Ismail Khan, Pakistan. Wheatyield is low in the system due to late sowing of wheat because oflate harvest of the preceding rice crop. Wheat sown after midNovember reduces yield by 1–1.5% for each successive delay perday (Hobbs et al., 1988). In conventional method of wheat sowingfarmers adopt several ploughing and planking for land preparationafter rice harvest. In addition, field is irrigated once before landpreparation, which takes 30–35 days to come in proper moistcondition. Occasionally late rainfall in standing paddy crop andexcessive moisture in the soil further delay harvesting of ricewhich ultimately delay wheat sowing. The exhaustive RWCS

* Corresponding author. Tel.: +92 0966626394.

E-mail address: marwat7862003@yahoo.com (K. Usman).1 Fax: +92 91 9216520.

0167-1987/$ – see front matter � 2010 Elsevier B.V. All rights reserved.

doi:10.1016/j.still.2010.07.009

practiced with conventional tillage (CT) has resulted in lowermarginal returns (Ladha et al., 2000). CT deteriorate soil and waterquality and increase pollution of groundwater due to excessive useof pesticides, increase water logging and salinity (Qureshi et al.,2003). There are serious concerns about the future potential forproductivity growth, long-term sustainability of the irrigatedwheat in RWCS in pace with population growth (Ladha et al., 2003;Hobbs, 2007).

Reduced (RT) and zero tillage (ZT) are collectively described asconservation tillage. It reduces production costs, saves water,increases soil organic matter, prevents soil erosion, mitigatesgreenhouse gases from the soil, improves air quality, protectswildlife habitat and biodiversity, improves production and ensuresenvironmental safety (Gupta et al., 2002; Khan et al., 2004a,b). ZTresults in very little soil disturbance, often with simultaneous basalfertilizer application (Mehla et al., 2000). In contrast, CT involvesmultiple passes of the tractor to accomplish sowing operations,which usually delay wheat sowing and reduce wheat yield(Gangwar et al., 2005). Fuel prices are lower under conservationtillage (Nail et al., 2007). ZT is particularly attractive on clay soils, tominimize compaction and induce natural structure formation

Table 1Physico-chemical characteristics of the experimental field.

Characteristic Unit Value

Sand g kg�1 150

Silt – 450

Clay – 400

Textural class – Silty clay loam

pH – 7.8

Organic matter g kg�1 9

Total N – 1

Available P mg kg�1 7.82

Available K – 192

EC d S m�1 0.12

CEC m.e/100 g 19.2

CO3 m.e/L Nil

HCO3� mol/L 1.24

Cl� – 2.06

Ca + Mg – 5.2

K. Usman et al. / Soil & Tillage Research 110 (2010) 101–107102

(McGarry et al., 2000). Conservation tillage improved soil waterholding capacity and crop yield (Fabrizzi et al., 2005). However,Sharma et al. (2004) reported that CT and ZT gave comparableyield, while Guzha (2004) observed lower wheat yields from ZTand RT than those from CT.

Both grassy and broad-leaved weeds infest wheat crop. Amonggrassy weeds Phalaris minor Retz. and among broad-leaved weedsRumex dentatus L. are of major concern in irrigated wheat underRWCS (Chhokar et al., 2008). Besides reduction in yield, P. minor athigher density causes crop lodging thus integrated approachesinvolving rotations of crops, tillage practices, and some newherbicides (e.g. fenoxaprop-p-ethyl and carfentrazone ethyl ester)were tested for proper recommendation. Because manual weedingis less effective under heavy soils and grassy weed infestation,particularly P. minor which is morphologically similar to wheatcrop and difficult to identify in the early growth stage (Bhan andKumar, 1997). Reddy et al. (2003) reported that manual weedingeffectively controls weeds but chemical weeding proved to be themost economical method as the former one is tedious, timeconsuming, often not available at the time of need, is veryexpensive and may result in stand losses.

The use of ZT for wheat planting is emerging as a new tool inintegrated weed management. It reduces weed population (Mehlaet al., 2000) and in conjunction with new herbicides provideseffective weed control (Ali and Tunio, 2002). Continuous use of CTdecrease wheat production in RWCS, therefore, there is a need tomodify current tillage practices (Atreya et al., 2006). ZT or RT withappropriate herbicide has been suggested as the possible solution.However, a shift from an intensive tillage system to ZT/RT cancause major changes in soil micro climates, which may affect weeddensity depending upon the soil and climatic conditions,particularly in early and late sowing of wheat in RWCS (Zentneret al., 2002). No studies have been conducted in Pakistan on the useof herbicides and tillage practices on weed control and wheat yieldin RWCS. The aim of this study was to evaluate the effect of tillagesystems and herbicides on weed control efficiency (WCE) andwheat yield under RWCS.

2. Materials and methods

2.1. Experimental site

Two years field experiments were conducted at Research Farm,Faculty of Agriculture, Gomal University, Dera Ismail Khan,Pakistan, during the years 2007–2009. Dera Ismail Khan (318 490

N, 708 550 E) is the southern district of the Khyber PakhtoonkhwaProvince (KPK) of Pakistan. The experimental site has an altitude of165 m. It is hot and dry in summer with moderate spells of rainduring the monsoon season; March, July, and August are thewettest months (Baloch et al., 2007). The experimental soil wasstrongly calcareous in nature.

2.2. Soil analysis

Soil samples were collected from the experimental site andanalyzed for physico-chemical characteristics before sowing(Table 1). The soil of the experimental field was silty clay loam,calcareous, alkaline in reaction (pH 7.8), low in organic matter(9 g kg�1), total N (1 g kg�1), AB-DTPA extractable P (7.8 mgP2O5 kg�1 soil) and high in available K (192 mg K2O kg�1 soil).Organic matter was determined through wet oxidation based uponthe Walkley and Black method (Nelson and Sommers, 1982). TotalN for 0–20 cm depth in soil was determined by the Kjeldhaldigestion, distillation and titration method as described inBremner and Mulvaney (1982). Phosphorus was measured byspectrophotometer and potash by flame photometer. The extract-

able P and K in soil samples were determined by the AB-DTPAextractable method (Soltanpour, 1985).

2.3. Experimental procedure

To study the effects of different herbicides and tillage systems onweed control and wheat production under RWCS an experiment wasconducted for two consecutive years in 2007–2009. Three tillagepractices viz. zero tillage (ZT), reduced tillage (RT) (includedrotavator followed by seed drilling machine), conventional tillage(CT) (comprised of disk plow, cultivator, rotavator, and seed drillingmachine), and five herbicide treatments viz. 2,4-dichlorophenoxyacetic acid (2,4-D), fenoxaprop-p-ethyl (Puma super 75 EW), 2,4-D + Puma super at 1.25 L ha�1 each, carfentrazone ethyl ester + -isoproturon (Affinity 50 WDG) at 2.00 kg ha�1, and control (weedycheck) were applied in randomized complete block design with splitplots arrangement and four replications. Tillage was allotted to mainplots, while herbicides were applied to subplots. Wheat varietyNasir-2000 recommended for irrigated areas was planted in 30-cmwide rows on October 29, 2007 and November 3, 2008 after riceharvest. A uniform seed rate of 120 kg ha�1 was used for the wholeexperiment. The size of subplot was 5 m� 1.8 m having 6 rows 5 mlong and 0.3 m apart. A standard dose of 120:60 kg N:P ha�1 wasused in the form of urea and triple supper phosphate (TSP). All thephosphorous and half of the nitrogen were applied with sowing,while remaining half of the nitrogen was applied in two splits at thefirst and second irrigation. The crop was harvested on May 16, 2008and May 20, 2009 during 2 years of experimentation. Temperatureand rainfall data were obtained from the meteorological station, D.I.Khan located near the experimental site (Table 2).

The main weeds present in the trials were P. minor, R. dentatus,Chenopodium album, Medicago denticulta, Melilotus indica, andlimited species of Cyprus rotundus, Malva perviflora, Cynodan

dactylon and Avena fatua. Data were recorded on weed controlefficiency, grain yield, net benefit and benefit cost ratio. Weeddensity m�2 was recorded 30 days after sowing before herbicidesspray. A square quadrate of 1 m2 was randomly put at three places ineach treatment and average weed counts m�2 was recorded in eachtreatment. Thirty days after herbicides spray, weed density m�2 wasagain recorded. Weed control efficiency of the different treatmentswas calculated by the following formula (Barros et al., 2007):

WCE ¼ 100� ðC2� dÞC1

100

where WCE is the weed control efficiency of the treatment (%), C1the weeds density m�2 counted before the treatment, C2 the weedsdensity m�2 recorded 1month after the treatment and d is thedifference in the weeds density m�2 between the first and secondcount in the untreated (control) plots (re-infestation).

Table 2Mean monthly air temperature and rainfall of experimental site during the years 2007–2008, 2008–2009 crop growing seasons, and 30 years average.

Year 1 (2007–2008) Year 2 (2008–2009) 30 years average

Month Temp. 8C Rainfall (mm) Temp. 8C Rainfall (mm) Temp.8C Rainfall (mm)

Max Min Average Max Min Average

October 34.2 17.1 25.7 0 33.9 20 27 0 25.2 5.8

November 26.5 13.1 19.8 1.1 28.9 10.9 19.9 0 19.4 2.2

December 21.4 6.8 14.1 1.4 23 6.7 14.9 17.3 14.0 8.8

January 18.3 4.1 11.2 5.2 21.4 6 13.7 7.6 12.4 11.4

February 22.1 6.8 14.5 24.2 23.7 9.2 16.5 25 14.8 15.0

March 31.4 15.4 23.4 1.8 28 13.4 20.7 36.6 19.6 37.4

April 33.1 18.9 26 37.2 33.2 18.4 25.8 21.1 25.9 24.1

May 39.1 24.2 31.7 16.9 37 23 30 24 31.2 17.0

Total rainfall 87.8 131.6 121.7

Table 3Break-up of total cost of production (US $ ha�1) for crop season 2007–2008 and 2008–2009.

Year Treatment Inputs cost ($ ha�1)

Tillage Herbicide Seed Ploughing Irrigation water Fertilizer Chemical Harvesting Threshing Total cost

2007–2008 ZT H1* 29.3 12.2 12.2 120.9 4.9 36.6 24.4 240.5

H2 29.3 12.2 12.2 120.9 10.7 36.6 24.4 246.2

H3 29.3 12.2 12.2 120.9 15.6 36.6 24.4 251.1

H4 29.3 12.2 12.2 120.9 15.2 36.6 24.4 250.8

H5 29.3 12.2 12.2 120.9 – 36.6 24.4 235.5

RT H1 29.3 24.4 12.2 120.9 4.9 36.6 24.4 252.6

H2 29.3 24.4 12.2 120.9 10.7 36.6 24.4 258.4

H3 29.3 24.4 12.2 120.9 15.6 36.6 24.4 263.3

H4 29.3 24.4 12.2 120.9 15.2 36.6 24.4 263.0

H5 29.3 24.4 12.2 120.9 – 36.6 24.4 247.7

CT H1 29.3 54.9 12.2 120.9 4.9 36.6 24.4 283.1

H2 29.3 54.9 12.2 120.9 10.7 36.6 24.4 288.9

H3 29.3 54.9 12.2 120.9 15.6 36.6 24.4 293.8

H4 29.3 54.9 12.2 120.9 15.2 36.6 24.4 293.4

H5 29.3 54.9 12.2 120.9 – 36.6 24.4 278.2

2008–2009 ZT H1 33.7 12.2 12.2 159.1 5.5 36.6 24.4 283.6

H2 33.7 12.2 12.2 159.1 15.2 36.6 24.4 293.3

H3 33.7 12.2 12.2 159.1 20.7 36.6 24.4 298.8

H4 33.7 12.2 12.2 159.1 15.2 36.6 24.4 293.3

H5 33.7 12.2 12.2 159.1 – 36.6 24.4 278.1

RT H1 33.7 24.4 12.2 159.1 5.5 36.6 24.4 295.8

H2 33.7 24.4 12.2 159.1 15.2 36.6 24.4 305.5

H3 33.7 24.4 12.2 159.1 20.7 36.6 24.4 311.0

H4 33.7 24.4 12.2 159.1 15.2 36.6 24.4 305.5

H5 33.7 24.4 12.2 159.1 – 36.6 24.4 290.3

CT H1 33.7 54.9 12.2 159.1 5.5 36.6 24.4 326.3

H2 33.7 54.9 12.2 159.1 15.2 36.6 24.4 336.0

H3 33.7 54.9 12.2 159.1 20.7 36.6 24.4 341.5

H4 33.7 54.9 12.2 159.1 15.2 36.6 24.4 336.0

H5 33.7 54.9 12.2 159.1 – 36.6 24.4 320.8

H1 = 2,4-D, H2 = Puma super, H3 = 2,4-D + Puma super, H4 = Affinity, H5 = Control.

Note: Inputs were uniformly applied in both the years, however, due to price variation cost of inputs varied accordingly.

K. Usman et al. / Soil & Tillage Research 110 (2010) 101–107 103

Grain yield was recorded by harvesting four central rows ineach subplot, tied into bundles, air dried, threshed, cleaned andgrains obtained were weighed with electronic balance andconverted into kg ha�1. Data were collected on inputs cost suchas seed, fertilizer, herbicides, and operational costs i.e. landpreparation, irrigation, harvesting and threshing (Table 3). Grossmargin or net benefit (NB) was determined by subtracting totalcost of production from gross income. Benefit cost ratio wascalculated from gross income divided by total cost of production(Ozpinar, 2006).

2.4. Statistical analysis

The data across 2 years of the experiment was statisticallyanalyzed using analysis of variance techniques appropriate for

randomized complete block design with split plot arrangementcombined over 2 years according to MSTATC (Steel and Torrie,1980). Upon obtaining significant F values, least significantdifference (LSD) test was employed for the separation of meansand their interaction at 0.05 level of probability.

3. Results and discussion

3.1. Weather data

The second growing season (2008–2009) was cooler and wetterthan first season (2007–2008) (Table 2). The precipitation washigher in the second season (132 mm) compared with first season(88 mm). The more favorable moisture and temperature in secondseason resulted in higher yield than first season (2007–2008).

Table 4Mean square values of WCE, grain yield, net benefit and BCR as affected by year, tillage and herbicides application.

Source D.F WCE Grain yield Net benefit BCR

Year (Y) 1 1950.3* 358,602** 7,049,721,598** 0.004NS

Rep (y*) 6 348 3883 1,599,446 0.002

Tillage (T) 2 131.4 NS 134,439** 429,432,737** 7.804**

Y�T 2 86.2 NS 1,866,472** 893,069,032** 1.284**

Error a 12 230.1 2201 896,113 0.004

Herbicides (H) 3/4a 18437.3** 34,876,797** 15,657,823,480 ** 24.354**

Y�H 3/4a 1469.4** 317,328** 390,087,635** 0.231**

T�H 6/8a 524.1* 461,026** 224,907,139** 0.422**

Y�T�H 6/8a 97.2 NS 343,058** 170,645,171** 0.270**

Error b 54/72a 229.2 767 327,051 0.001

NS, non significant; Rep (y*), replication over year.a D.F for grain yield, net benefit and BCR.* Significant at the 0.05 probability levels.** Significant at the 0.01 probability levels

K. Usman et al. / Soil & Tillage Research 110 (2010) 101–107104

3.2. Weed control efficiency (WCE)

Weed control efficiency (WCE %) was significantly affected byyears (Y), herbicides (H), Y� H, and tillage (T) � H interaction(Table 4). The WCE (73.1%) was higher in 2008–2009 compared to2007–2008 (64.0%) (Table 5). The higher WCE in 2008–2009 may bedue to favorable temperature and rainfall in addition to effectiveweed management with herbicides and tillage. WCE of both Affinity(94.1%) and 2,4-D + Puma super (90.9%) was higher, while bothPuma super (44.1%) and 2,4-D (45.1%) applied alone resulted inlowest WCE. The higher WCE of Affinity may be attributed to itsbroad spectrum activity and its higher phytotoxic effects againstboth grass and broad-leaved weeds compared to other herbicide.Combination of 2,4-D + Puma super also performed better but theirhigher doses caused crop injury. In Y � H interaction, Affinity and2,4-D + Puma super recorded the highest WCE (90.3–95.3%) in boththe years. The higher weed control efficiency with broad spectrumherbicides may be attributed to their higher phytotoxic effectsagainst both broad and narrow-leaved weeds compared to otherherbicides, when applied as post emergence (Khan et al., 2004a,b).

Mean values for T � H revealed that higher WCE (88.8–97%)was recorded with Affinity and with 2,4-D + Puma super,irrespective of the tillage, while lower WCE (30.9%) was recordedwith Puma super from ZT. These results clearly indicate

Table 5Weed control efficiency (WCE %) of wheat as affected by year, tillage and herbicides d

Year Herbicide (H) Tillage (T)

Zero Mean� S.D. Re

2007–2008 2,4-D 48.7�12.6

Puma supper 15.2�23.1

2,4-D + Puma supper 89.9�5.3

Affinity 92.5�9.3

Weedy check –

2008–2009 2,4-D 59.7�12.5

Puma supper 46.7�17.5

2,4-D + Puma supper 93.8�4.6

Affinity 90.5�9.4

Weedy check –

2,4-D 54.2 b�12.6 40

Puma supper 30.9 c�20.3

2,4-D + Puma supper 91.9 a�5.0

Affinity 91.5 a�9.4

Weedy check –

Year1 61.6�12.6

Year2 72.7�11.0

Tillage 67.1�11.8

Means followed by same letter (s) or no letter in each category are not significantly dif

S.D. = standard deviation.

superiority of Affinity and 2,4-D + Puma super over otherherbicide treatments.

3.3. Grain yield

Year (Y), T, H, Y � H, T � H and Y � T � H interactionsignificantly affected grain yield (Table 4). Higher grain yield(5601 kg ha�1) was recorded in 2008–2009 compared to 2007–2008 (Table 6). The lower yield in 2007–2008 may be due to lowerrainfall and higher average temperature particularly in March toMay (Table 2) resulting in reduction of yield (Pathak et al., 2003).Mean values for herbicides revealed that combination of herbi-cides with broad spectrum activity showed better performancethan their sole application. Highest grain yield (6907 kg ha�1) wasrecorded with Affinity followed by 2,4-D + Puma super(6348 kg ha�1), while weedy check produced lowest grain yieldof 3766 kg ha�1. In Y x H interaction, maximum grain yield(6996 kg ha�1) was recorded with Affinity in second year, whileminimum grain yield (3690 kg ha�1) was recorded in weedy checkin the same year. High precipitation and low average temperaturemay be accounted for higher yield in second year (Baghestani et al.,2008; Chhokar et al., 2008).

Mean values for T revealed that both RT (5584 kg ha�1) and ZT(5575 kg ha�1) produced higher grain yield compared to CT

uring two growing seasons.

Mean� S.D.

duced mean� S.D. Conventional Mean� S.D.

45.4�38.3 37.1�20.4 43.7 c�23.8

32.3�10.2 36.3�19.7 27.9 d�17.6

92.6�4.4 92.3�2.9 91.6 a�4.2

90�2.9 96.5�2.0 93.0 a�4.7

– – –

35.4�33.9 44.2�16.3 46.5 c�20.9

62.8�16.6 71.2�10.1 60.2 b�14.7

85�8.3 92�7.8 90.3 a�6.9

97.9�2.5 97.5�4.7 95.3 a�5.5

– – –

.4 bc �36.1 40.6 bc�18.4 45.1 b�22.4

47.5 b�13.4 53.8 b�14.9 44.1 b�16.2

88.8 a�6.4 92.1 a�5.4 90.9 a�5.6

94.0 a�2.7 97.0 a�3.4 94.1 a�5.2

– – –

65�14.0 65.5�11.3 64.0 b�12.6

70.3�15.3 76.2�9.7 73.1 a�12.0

67.7�14.7 70.9�10.5 –

ferent (P<0.05) using LSD test (this definition will apply to all other data tables).

Table 6Grain yield (kg ha�1) of wheat as affected by tillage and herbicides during two growing seasons.

Year Herbicide (H) Tillage (T) Mean� S.D.

Zero (mean� S.D.) Reduced (mean� S.D.) Conventional (mean� S.D.)

2007–2008 2,4-D 5619 i�22.5 5361 k�1.7 5501 j�2.7 5494 f�9.0

Puma super 5022 n�57.2 4896 p�77.6 5623 i�9.8 5180 g�48.2

2,4-D + Puma super 6092 e�75.5 5787 h�69.4 6491 d�8.2 6123 d�51.1

Affinity 6860 b�7.5 6600 c�81.7 6995 a�3.3 6818 b�30.8

Weedy check 3926 s� 0.8 3966 r�46.7 3634 t�23.6 3842 I�23.7

2008–2009 2,4-D 5847 g�18.4 6021 f�15.2 4943 o�4.1 5604 e�12.6

Puma super 4928 op�8.5 5190 m�8.2 5305 l�3.6 5141 h�6.8

2,4-D + Puma super 6963 a�2.2 6977 a�6.3 5780 h�4.1 6574 c�4.2

Affinity 6997 a�1.3 6995 a�3.6 6995 a�1.3 6996 a�2.0

Weedy check 3497 u�5.0 4045 q�61.1 3527 u�20.6 3690 j�28.9

2,4-D 5733 g�20.5 5691 h�8.5 5222 j�3.4 5549 c�10.8

Puma super 4975 l�32.9 5043 k�42.9 5464 i�6.7 5161 d�27.5

2,4-D + Puma super 6527 d�38.9 6382 e�37.9 6135 f�6.2 6348 b�27.7

Affinity 6929 b�4.4 6797 c�42.7 6995 a�2.3 6907 a�16.5

Weedy check 3712 n�2.9 4006 m�53.9 3581 o�22.1 3766 e�26.3

Year1 5504 c�32.7 5322 d�55.4 5649 b�9.5 5491 b�32.5

Year2 5647 b�7.1 5846 a�18.9 5310 d�6.7 5601 a�10.9

Tillage 5575 a�19.9 5584 a�37.2 5479 b�8.1

K. Usman et al. / Soil & Tillage Research 110 (2010) 101–107 105

(5479 kg ha�1). The higher yield in ZT and RT is ascribed to drasticreduction of weeds growth and population particularly P. minor

and enhanced fertilizer and water-use efficiency (Mehla et al.,2000; Mari et al., 2003; Erenstein et al., 2008). In Y � T interaction,highest grain yield was recorded in RT (5846 kg ha�1) followed byZT (5647 kg ha�1) in 2008–2009, while lowest grain yield(5310 kg ha�1) was recorded in CT in 2008–2009.

The T � H interaction revealed that maximum grain yield(6995 kg ha�1) was obtained from Affinity � CT followed byAffinity � ZT (6929 kg ha�1), while minimum grain yield(3581 kg ha�1) was obtained from CT �weedy check (Chhokaret al., 2007). Combination of ZT and H have significantly increasedwheat yield in different environments of the world by reducingweeds infestation and resulting in higher grain yield compared tofarmer’s practice of wheat sowing. However, the magnitude ofincrease varied is rather site specific and dependent on the type ofT and H used (Chhokar et al., 2007). The results further showed thatgrain yield of weedy check � RT was higher than ZT �weedy check

Table 7Net benefit (aUS $ ha�1) of wheat as affected by tillage and herbicides during two grow

Year Herbicide Tillage

Zero Mean� S.D. Red

2007–2008 2,4-D 1130.0 l�449 105

Puma supper 978.7 o�1144 93

2,4-D + Puma supper 1234.6 j�1511 114

Affinity 1422.5 e�149 134

Weedy check 722.1 r�16 71

2008–2009 2,4-D 1356.5 h�423 139

Puma supper 1089.0 m�195 115

2,4-D + Puma supper 1654.3 bc�51 164

Affinity 1669.1 a�30 165

Weedy check 702.8 s�114 84

2,4-D 1243.3 g�436 122

Puma supper 1033.9 l�670 104

2,4-D + Puma supper 1444.5 d�781 139

Affinity 1545.8 a�90 150

Weedy check 712.4 n�65 782

Year1 1097.6 d�654 104

Year2 1294.4 b�163 133

Tillage 1196.0 a�409 118

a 1US $ = Pak Rs.82/- during 2009 currency rate.

and CT �weedy check in both years. One of the reasons may behigher density of M. denticulata and M. indica in RT which areleguminous in nature having complementary effects on wheat cropand detrimental effects on other weeds (Banik et al., 2007). InY � T � H interaction, broad spectrum herbicides, (Affinity and2,4-D + Puma super) performed better in 2008–2009 compared to2007–2008 in ZT and RT.

3.4. Gross margin or net benefit (NB)

Y, T, H, Y � H, T � H and Y � T � H significantly affected NB(Table 4). Higher NB (US $ 1263 ha�1) was recorded in 2008–2009compared to 2007–2008 (Table 7). Mean values for H revealed thatNB increased with H and maximum NB ($ 1522 ha�1) was recordedwith Affinity followed by 2,4-D + Puma super ($ 1375 ha�1),while lowest NB ($ 711 ha�1) was observed for weedy check. It isevident from the results that broad spectrum herbicides performedbetter due to timely and effective control of both broad- and

ing seasons.

Mean� S.D.

uced mean� S.D. Conventional mean� S.D.

4.9 n�35 1058.6 n�54 1081.2 g�179

5.9 p�1552 1082.5 m�197 999.0 h�964

8.1 k�1389 1289.2 i�164 1224.0 e�1021

6.7 h�1633 1412.5 f�66 1393.9 c�616

9.6 r�935 608.2 u�472 683.3 j�474

2.9 g�349 1060.1 n�95 1269.9 d�289

0.3 k�188 1152.1 k�83 1130.4 f�156

6.0 c�144 1279.8 i�95 1526.7 b�97

6.5 b�82 1626.1 d�29 1650.5 a�47

4.4 q�1405 668.5 t�473 738.6 I�664

3.9 h�192 1059.4 j�75 1175.5 c�234

3.1 k�870 1117.3 i�140 1064.7 d�560

7.0 e�767 1284.5 f�130 1375.3 b�559

1.6 c�858 1519.3 b�48 1522.2 a�332

.0 m�1170 638.3 o�473 710.9 e�569

1.0 e�1109 1090.2 d�191 1076.3 b�651

8.0 a�434 1157.3 c�155 1263.2 a�251

9.5 b�772 1123.8 c�173

Table 8Benefit cost ratio (BCR) of wheat as affected by tillage and herbicides during two growing seasons.

Year Herbicide (H) Tillage (T) Mean� S.D.

Zero mean� S.D. Reduced mean� S.D. Conventional mean� S.D.

2007–2008 2,4-D 5.7 h� 0.02 5.2 j� 0.00 4.7 m� 0.00 5.2 f� 0.01

Puma supper 5.0 k� 0.06 4.6 n� 0.07 4.7 m� 0.01 4.8 g� 0.05

2,4-D + Puma supper 5.9 f� 0.07 5.4 I� 0.06 5.4 I� 0.01 5.6 d� 0.05

Affinity 6.7 a� 0.01 6.1 e� 0.08 5.8 g� 0.00 6.2 b� 0.03

Weedy check 4.1 q� 0.00 3.9 s� 0.05 3.2 u� 0.02 3.7 I� 0.02

2008–2009 2,4-D 5.8 g� 0.02 5.7 h� 0.01 4.2 p� 0.00 5.2 e� 0.01

Puma supper 4.7 m� 0.01 4.8 l� 0.01 4.4 o� 0.00 4.6 h� 0.01

2,4-D + Puma supper 6.5 b� 0.00 6.3 d� 0.01 4.7 m� 0.00 5.8 c� 0.00

Affinity 6.7 a� 0.00 6.4 c� 0.00 5.8 g� 0.00 6.3 a� 0.00

Weedy check 3.5 t� 0.01 3.9 r� 0.06 3.1 v� 0.02 3.5 j� 0.03

2,4-D 5.8 f� 0.02 5.5 g� 0.01 4.5 l� 0.00 5.2 c� 0.01

Puma supper 4.9 I� 0.03 4.7 j� 0.04 4.6 k� 0.01 4.7 d� 0.03

2,4-D + Puma supper 6.2 c� 0.04 5.8 d� 0.03 5.1 h� 0.01 5.7 b� 0.03

Affinity 6.7 a� 0.00 6.3 b� 0.04 5.8 e� 0.00 6.3 a� 0.02

Weedy check 3.8 n� 0.00 3.9 m� 0.05 3.2 o� 0.02 3.6 e� 0.02

Year1 5.5 a� 0.03 5.0 c� 0.05 4.8 d� 0.01 5.1� 0.03

Year2 5.4 b� 0.01 5.4 b� 0.02 4.5 e� 0.01 5.1� 0.01

Tillage 5.5 a� 0.02 5.2 b� 0.04 4.6 c� 0.01

K. Usman et al. / Soil & Tillage Research 110 (2010) 101–107106

narrow-leaved weeds causing higher net economic return. In Y � Hinteraction, maximum NB ($ 1651 ha�1) was recorded with Affinityin 2008–2009, while minimum NB ($ 683 ha�1) was recorded inweedy check in 2007–2008. The higher economic return in 2008–2009 from Affinity may be due to favorable temperature andprecipitation and more availability of resources to crop (Shah et al.,2004).

Mean values for T revealed that highest NB was obtained fromZT ($ 1196 ha�1) followed by RT ($ 1190 ha�1), while lowest NBwas obtained from CT ($ 1124 ha�1). The higher NB from ZT and RTis ascribed to higher grain yield, low cost of production, reducedweed growth and population, enhanced fertilizer and water-useefficiency (Mari et al., 2003; Ozpinar, 2006; Erenstein et al., 2008).In Y � T interaction, maximum NB ($ 1338 and $ 1294 ha�1) wasrecorded in RT and ZT in 2008–2009, while minimum NB ($ 1041and $ 1090 ha�1) was recorded in RT and CT in 2007–2008,respectively. In T � H interaction, maximum NB ($ 1546 ha�1) wasobtained from ZT � Affinity, while minimum NB ($ 638 ha�1) wasobtained from CT �weedy check. Combination of ZT/RT andherbicide significantly reduced weeds population particularly P.

minor, which increased wheat economic returns by increasingyield (Nail et al., 2007; Chhokar et al., 2007). In Y � T � Hinteraction, maximum NB ($ 1669 ha�1) was obtained fromZT � Affinity in 2008–2009, while minimum NB ($ 608 ha�1)was obtained from CT �weedy check in 2007–2008. The overallresults suggest economic superiority of ZT and RT over CT. ZT andRT might have environmental impacts like carbon sequestration,fuel saving, and reduced risk of soil erosion, surface and groundwater pollution, improvement in soil physical and chemicalstructure, increase in soil organic carbon and soil N. Moreover,ZT/RT retain crop residues at the soil surface, avoid the deleteriouseffects of intensive tillage practices on soil structure and fertility,improve water- and nutrient-use efficiencies, mitigate green housegases emission, reduce energy consumption, enrich soil biota thatcan improve nutrient recycling (Conant et al., 2007; Fernandezet al., 2007).

3.5. Benefit cost ratio (BCR)

Analysis of the data revealed that BCR was significantly affectedby T, H, Y � T, Y � H, T � H and Y � T � H interactions (Table 4).The highest BCR (5.5) was recorded in ZT followed by RT (5.2),

while the lowest BCR (4.6) was recorded in CT (Table 8). In Y � T,maximum BCR (5.5) was recorded in ZT in 2007–2008, whileminimum BCR (4.5) was recorded in CT in 2008–2009. The higherBCR from ZT and RT is ascribed to higher grain yield, and lower costof production than CT. The lower BCR under CT might be due tohigher cultivation cost in addition to provision of favorableenvironment for weeds particularly P. minor and R. dentatus whichheavily dominated the wheat crop causing reduction in grain yieldcompared to ZT/RT (Mehla et al., 2000; Chhokar et al., 2007).

Mean values for herbicides revealed that herbicides signifi-cantly increased BCR compared with weedy check. Maximum BCR(6.3) was recorded with Affinity followed by 2,4-D + Puma super(5.7) (Table 8). In Y � H interaction, maximum BCR (6.3) wasrecorded with Affinity in 2008–2009, while minimum BCR (3.5)was recorded in weedy check in the same year. The highest BCRwith Affinity could be due to its highest phytotoxic effect againstdiverse flora of weeds. In addition to increase in BCR, herbicides aretime saving and economical compared to other methods of weedcontrol (Shah et al., 2004).

In T � H interactions, maximum BCR (6.7) was recorded inZT � Affinity, while minimum BCR (3.2) was recorded inCT �weedy check. Combinations of ZT/RT and H have significantlyresulted in viable economic returns. However, the quantum ofincrease may vary from area to area and dependent on the type oftillage and herbicides used. In Y � T � H interaction, maximumBCR (6.7) was recorded from ZT � Affinity in both years, whileminimum BCR (3.1) was recorded in CT �weedy check in 2008–2009. The results clearly shows economic superiority of ZT/RT overCT. ZT seems to be most feasible, cost effective and viable optioncompared to CT for adoption by farming community.

4. Conclusion

P. minor, R. dentatus and C. album are the major weeds in wheatunder RWCS in arid climate of Northwestern Pakistan. The resultsrevealed that ZT and RT produced higher grain yield, NB and BCRcompared to CT. Weeds were effectively controlled with Affinityand 2,4-D + Puma super compared with other herbicide treat-ments. However, higher doses of these herbicides may causesevere crop injury. Affinity in combination with ZT is moreproductive and economical than RT and CT. Intensive tillagepractices are not always necessary to control weeds and produce

K. Usman et al. / Soil & Tillage Research 110 (2010) 101–107 107

higher yield. ZT in combination with broad spectrum herbicidesuch as Affinity may effectively control weeds, reduce cost ofproduction, increase grain yield, and economic return in RWCS.

Acknowledgement

The authors thank the Gomal University, D.I. Khan, Pakistan forpartial support.

References

Ali, Q.M., Tunio, S., 2002. Effect of various planting patterns on weed population andyield of wheat. Asian J. Plant Sci. 1 (93), 216–217.

Atreya, K., Sharma, S., Bajracharya, R.M., Rajbhandari, N.P., 2006. Applications ofreduced tillage in hills of central Nepal. Soil Till. Res. 88, 16–29.

Baghestani, M.A., Zand, E., Soufizadeh, S., Beheshtian, M., Haghighi, A., Barjasteh, A.,Birgani, D.G., Deihimfard, R., 2008. Study on the efficacy of weed control inwheat (Triticum aestivum L.) with tank mixtures of grass herbicides withbroadleaved herbicides. Crop Prot. 27, 104–111.

Baloch, M.S., Awan, I.U., Hassan, G., Zubair, M., 2007. Studies on plant populationand stand establishment techniques for increasing productivity of rice in DeraIsmail Khan. Pak. Rice Sci. 14 (2), 118–124.

Banik, P., Pramanik, P., Sarkar, R.R., Bhattacharya, S., Chattopadhayay, J., 2007. Amathematical model on the effect of M. denticulata weed on different wintercrops. Biosystems 90, 818–829.

Barros, J.F.C., Gottlieb, B., Carvalho, M., 2007. Effect of reduced doses of a post-emergence herbicide to control grass and broad-leaved weeds in no-till wheatunder Mediterranean conditions. Crop Prot. 26, 1538–1545.

Bhan, V.M., Kumar, S., 1997. Integrated management of Phalaris minor in rice–wheat ecosystems in India. In: Proceedings of International Conference onEcological Agriculture: Towards Sustainable Development, vol. 2, Chandigarh,India, November 15-17, pp. 400–415.

Bremner, J.M., Mulvaney, C.S., 1982. Nitrogen – total. In: Page, A.L., Miller, R.H.,Keeney, D.R. (Eds.), Methods of Soil Analysis. Part II. Chemical and Microbio-logical Properties. 2nd ed. American Society of Agronomy, Madison, WI, USA,pp. 595–682.

Chhokar, R.S., Sharma, R.K., Jat, G.R., Pundir, A.K., Gathala, M.K., 2007. Effect of tillageand herbicides on weeds and productivity of wheat under rice–wheat growingsystem. Crop Prot. 26, 1689–1696.

Chhokar, R.S., Singh, S., Sharma, R.K., 2008. Herbicides for control of isoproturon-resistant little seed Canary grass (Phalaris minor) in wheat. Crop Prot. 27, 719–726.

Conant, R.T., Easter, M., Paustian, K., Swan, A., Williams, S., 2007. Impacts of periodictillage on soil C stocks: a synthesis. Soil Till. Res. 95, 1–10.

Erenstein, O., Farooq, U., Malik, R.K., Sharif, M., 2008. On-farm impacts of zero tillagewheat in South Asia’s rice–wheat systems. Field Crops Res. 105, 240–252.

Fabrizzi, K.P., Garcıa, F.O., Costa, J.L., Picone, L.I., 2005. Soil water dynamics, physicalproperties and corn and wheat responses to minimum and no-tillage systems inthe southern Pampas of Argentina. Soil Till. Res. 81, 57–69.

Fernandez, R.O., Fernandez, P.G., Cervera, J.V.G., Torres, F.P., 2007. Soil propertiesand crop yields after 21 years of direct drilling trials in southern Spain. Soil Till.Res. 94, 47–54.

Gangwar, K.S., Singh, K.K., Sharma, S.K., Tomar, O.K., 2005. Alternative tillage andcrop residue management in wheat after rice in sandy loam soils of Indo-Gangetic plains. Soil Till. Res. 88, 242–252.

Gupta, R.K., Hobbs, P.R., Ladha, J.K., Prabhakar, S.V.R.K., 2002. Resource conservationtechnologies. In: Transforming the rice–wheat system of the Indo-GangeticPlains, Asia-Pacific Association of Agricultural Research Institutions, FAO Re-gional Office for Asia and the Pacific, Bangkok, p. 42.

Guzha, A.C., 2004. Effects of tillage on soil micro relief, surface depression storageand soil water storage. Soil Till. Res. 76, 105–114.

Hobbs, P.R., Mann, C.E., Buttler, L., 1988. A perspective on research needs for rice–wheat rotation. In: Klott, A.R. (Ed.), Wheat Production. CIMMYT, Mexico, pp.197–211.

Hobbs, P.R., 2007. Conservation agriculture: what is it and why is it important forfuture sustainable food production? J. Agric. Sci. 145, 127–137.

Khan, I., Hassan, G., Khan, M.I., Khan, E.A., 2004a. Efficacy of some new herbicidalmolecules on grassy and broadleaf weeds in wheat-II. Pak. J. Weed Sci. Res. 10(1–2), 33–38.

Khan, N.U., Khan, S.U., Hassan, G., 2004. Herbicides effect on weed flora and grainyield of zero vs. conventional tillage wheat. Paper Read at Fourth InternationalWeed Science Conference (IWSC), Durban, South Africa, June 20–24, 2004.S13MT17P04, Abstract. No. 300.

Ladha, J.K., Dawe, D., Pathak, H., Padre, A.T., Yadav, R.L., Singh, B.J., Singh, Y., Singh, Y.,Singh, P., Kundu, A.L., Sakal, R., Ram, N., Regmi, A.P., Gami, S.K., Bhandari, A.L.,Amin, R., Yadav, C.R., Battarai, E.M., Das, S., Aggarwal, H.P., Gupta, R.K., Hubbs,P.R., 2003. How extensive are yield declines in long term rice–wheat experi-ments in Asia? Field Crops Res. 81, 159–180.

Ladha, J.K., Fisher, K.S., Hossain, M., Hobbs, P.R., Hardy, B. (Eds.), 2000. Improving theproductivity and sustainability of rice–wheat systems of the Indo-GangeticPlains: a synthesis of NARS-IRRI partnership research. IRRI Discussion PaperSeries No. 40. IRRI, Los Banos, Philippines.

Mari, N., Khuhro, G.A., Tunio, G.S., Mailo, N., 2003. Zero-tillage sowing method ofwheat followed by transplanted rice. PARC-RWC. In: Proceedings of the Na-tional Workshop on rice–wheat systems, Islamabad, Pakistan, December 11-12,2002. Pakistan Agricultural Research Council, Islamabad, Pakistan and rice–wheat consortium for the Indo-Gangetic Plains, New Delhi, India p. 118.

McGarry, D., Bridge, B.J., Radford, B.J., 2000. Contrasting soil physical propertiesafter zero and traditional tillage of an alluvial soil in the semi-arid subtropics.Soil Till. Res. 53, 105–115.

Mehla, R.S., Verma, J.K., Gupta, R.K., Hobbs, P.R. (Eds.), 2000. Stagnation in theproductivity of wheat in the Indo-Gangetic plains: zero-till-seed-cum-fertilizerdrill as an integrated solution: Rice–Wheat Consortium Paper Series 8. Rice–Wheat Consortium for the Indo-Gangetic Plains, New Delhi, India, p 12.

Nail, E.L., Young, D.L., Schillinger, W.F., 2007. Diesel and glyphosate price changesbenefit the economics of conservation tillage versus traditional tillage. Soil Till.Res. 94, 321–327.

Nelson, D.W., Sommers, L.E., 1982. Total carbon, organic carbon, and organic matter.In: Page, A.L., Miller, R.H., Keeney, D.R. (Eds.), Methods of Soil Analysis, Part 2.Agronomy No 9, Madison, WI, USA. pp. 539–579.

Ozpinar, S., 2006. Effects of tillage systems on weed population and economics forwinter wheat production under the Mediterranean dry land conditions. Soil Till.Res. 87, 1–8.

Pathak, H., Ladha, J.K., Aggarwal, P.K., Peng, S., Das, S., Singh, Y., Singh, B., Kamra, S.K.,Mishra, B., Sastri, A.S.R.A.S., Aggarwal, H.P., Das, D.K., Gupta, R.K., 2003. Trendsof climatic potential and on-farms yields of rice and wheat in the Indo-GangeticPlains. Field Crops Res. 80, 223–234.

Qureshi, A.S., Shah, T., Akhtar, M., 2003. The groundwater economy of Pakistan.IWMI working paper 64. Pakistan country series No. 19. International watermanagement institute, Lahore, Pakistan.

Reddy, B.V.S., Reddy, P.S., Bidinger, F., Blummel, M., 2003. Crop management factorsinfluencing yield and quality of crop residues. Field Crops Res. 84, 57–77.

Shah, N.S., Hassan, G., Rahman, S.U., Ahmad, N., Subhan, F., 2004. Weed manage-ment in wheat on farmers, fields of DASP command area. Pak. J. Weed Sci. Res.10 (1–2), 25–32.

Sharma, R.K., Babu, K.S., Chhokar, R.S., Sharma, A.K., 2004. Effect of tillage ontermites, weed incidence and productivity of spring wheat in rice–wheatsystem of North Western Indian plains. Crop Prot. 23, 1049–1054.

Soltanpour, P.N., 1985. Use of ammonium bicarbonate-DTPA soil test to evaluateelemental availability and toxicity. Commun. Soil Sci. Plant Anal. 16, 322–338.

Steel, R.G.D., Torrie, J.H., 1980. Principles and Procedures of Statistics. McGraw HillBook Co. Inc., New York.

Zentner, R.P., Wall, D.D., Nagy, C.N., Smith, E.G., Young, D.L., Miller, P.R., Campbell,C.A., McConkey, B.G., Brandt, S.A., Lafond, G.P., Johnston, A.M., Derksen, D.A.,2002. Economics of crop diversification and soil tillage opportunities in theCanadian Prairies. Agron. J. 94, 216–230.