INTERNATIONAL JOURNAL OF AGRICULTURE & BIOLOGY 1560–8530/2003/05–4–530–532 http://www.ijab.org Integrated Weed Management in Wheat Grown in Irrigated Areas ABDUL KHALIQ 1 , KAZIM ALI† AND MOAZZAM IMRAN‡ Department of Agronomy, University of Agriculture, Faisalabad–38040, Pakistan †Shakargang Sugarcane Research Institute, Jhang–Pakistan ‡Syngenta Pakistan, Jhang, Pakistan 1 Corresponding author e-mail: khaliquaf@yahoo.com ABSTRACT Efficacy of integrated weed control in wheat was investigated during 1999-2000 at agronomic research area, University of Agriculture, Faisalabad. Treatments comprised weedy check, one hand weeding at 25 days after sowing (DAS), two hand weeding at 25 and 50 DAS, isoproturon @ 2 kg a.i. ha -1 as pre-emergence application, clodinophob @250 g a.i. ha -1 as post- emergence , isoproturon @ 2 kg a.i. ha -1 as pre-emergence + one hoeing 50 DAS and clodinophob @ 250 g a.i. ha -1 as post emergence + one hoeing 50 DAS. All the herbicidal treatments decreased weed population and dry weight over weedy check. Maximum grain yield (6.3 t ha -1 ) and harvest index (44.69%) was obtained in case of pre-emergence application of isoproturon @ 2 kg a.i. ha -1 + one hoeing 50 DAS, which however, remained at par with clodinophob @ 250 g a.i. ha -1 as post –emergence + one hoeing 50 DAS, isoproturon (pre-emergence) spray, two hoeing at 25 and 50 DAS and one hoeing at 25 DAS. Highest net income of Rs. 45625 ha -1 was obtained from pre emergence spray of isoproturon @ 2 kg a.i. ha -1 + one hoeing at 50 DAS. Key Words: Herbicides; Integrated weed management; Wheat INTRODUCTION Wheat is most important cereal crop in Pakistan. Weed infestation is a serious hindrance in realizing its higher yields at farmer’s fields. Uncontrolled weeds can reduce wheat yield by 15-20% and in serious cases may lead to complete failure of crop (Gill & Wallia, 1979). It has been reported that crop yield may be increased by about 37% by complete eradication of weeds (Jails & Shah, 1982). The problem of weed infestation is becoming more serious in irrigated areas, where cropping intensity is rapidly increasing with the result that weed management through fallowing, hoeing, harrowing and cultivating practices has become impossible and weedicides use has become inevitable for obtaining higher yield and better quality of produce. Majid and Hussain (1983) compared the effectiveness of Dicuran MA 60WP, Stomp 330EC, Buctril M 20% and Herbit 20% with hand weeding practice in wheat and concluded that Dicuran Ma 60WP controlled 96.8% weeds and increased yield by 37%. Pandey et al. (1996) demonstrated that post-emergence application of isoproturon and metaxuron @ 1 kg a.i. ha -1 and 2 kg a.i. ha - 1 , respectively gave excellent weed control in wheat. Singh et al. (1989) compared efficacy of cultural and chemicals methods for weed control in wheat and reported highest yield of 6.8 and 10.9 t ha -1 (of grain and straw respectively) from hand weeding and 6.6 and 10.9 t ha -1 , respectively, from pendimethalin @ 1 kg a.i. ha -1 . Satao et al. (1993) studied the effects of two hand weeding at 20 and 40 DAS, one hand weeding at 20 DAS, pre-emergence application of isoproturon and pre-emergence isoproturon + one hand weeding for the control of weeds in wheat. They reported increase in wheat grain in all treatments over control; however, two hand weeding resulted in highest yield during the two years. The objective of this study was, therefore, to investigate the effect of integrated weed management in wheat including both chemical and manual methods of control. MATERIALS AND METHODS A commercial wheat variety Inqulab-91 was sown in the month of November with the help of single row hand drill in 22.5 cm apart single rows using seed rate of 125 kg ha -1 in randomized complete block design. Net plot size was 1.8 x 10 m. N Nitrogen and phosphatic fertilizers @ 100 kg ha -1 each were applied. Treatments were weedy check (control), one hand weeding at 25 DAS, two hand weeding at 25 and 50 DAS, pre-emergence application of isoproturon @ 2 kg ha -1 (Proton 500WP), post-emergence application of clodinophob @ 250 g ha -1 (Topic 15WP), pre-emergence application of isoproturon @ 2 kg ha -1 + one hand weeding at 50 DAS post-emergence application of clodinophob @ 250 g ha -1 + one hand weeding 50 DAS. Five irrigations were applied in addition to rauni to raise the crop. From each plot a unit area of one square meter was taken at random for recording germination count, plant height, number of fertile tillers, spike length, number of grains per spike, 1000-grain weight, grain yield, straw yield, harvest index and weed count per unit area. Major weed flora of the