Economical weed management practices to enhance the production of clusterbean [Cyamopsis tetragonoloba (L.) Taub.]

A field experiment entitled studies on weed management and phosphorus fertilization in clusterbean was conducted consecutively during kharif 2015 and 2016 at Instructional Farm (Agronomy), Rajasthan College of Agriculture, Udaipur. The test crop (Clusterbean) was growing with eight weed management treatment in main plots [pendimethalin 1.0 kg ha-1 as Pre emergence (PE), pendimethalin 1.0 kg ha-1 as PE + hand weeding (HW) 30 DAS, pendimethalin + imazethapyr 0.8 kg ha-1 PE, pendimethalin + imazethapyr 0.8 kg ha-1 PE + HW 30 DAS, imazethapyr + imazamox 0.05 kg ha-1 at 15 DAS, imazethapyr + imazamox 0.05 kg ha-1 at 15 DAS + HW 30 DAS, HW at 15 & 30 DAS and weedy check] and four phosphorus (0, 20, 40 and 60 kg ha-1) levels in sub plots. Among different weed control treatments, hand weeding at 15 & 30 DAS, pre-emergence pendimethalin + imazethapyr (RM) 0.8 kg ha-1 PE + HW 30 DAS and post-emergence imazethapyr + imazamox (RM) 0.05 kg ha-1 15 DAS+HW 30 DAS were most effective in respect of reducing weed density, weed biomass, nutrient removal by weed and to promote yield and quality of clusterbean as compared to rest of other weed control treatments. Highest seed yield (1126 kg ha-1) and halum yield of clusterbean were observed in hand weeding at 15 & 30 DAS but maximum net return (Rs. 48125/-) was recorded in pendimethalin + imazethapyr (RM) 0.8 kg ha-1 PE + HW 30 DAS followed by imazethapyr + imazamox (RM) 0.05 kg ha-1 and two hand weeding at 15 & 30 DAS. Further, they were also found responsible for highest uptake of N, P and K by clusterbean crop and lowest uptake of these plant nutrients by weed plants. Application of 40 kg P2O5 ha-1 recorded significantly higher clusterbean yield and uptake of N, P and K by clusterbean crop and lowest uptake by weed plant sover rest of the treatments during both years of experimentation.