Impact of Wheat Establishment Methods and Weed Management Practices on Weed Flora, Yield and Nutrient Uptake of Wheat in Rice-Wheat Cropping System

Establishment methods and weed management practices on weed dynamics nutrient uptake of wheat

Abstract

A field experiment was conducted at the Crop Research Centre of Govind Ballabh Pant University of Agriculture and Technology Pantnagar, Udham Singh Nagar during continuous two years to study the weed flora, yield and nutrient uptake of wheat (Triticum aestivum L.) under different wheat establishment methods i.e. Zero tillage (sowing with zero till ferti-seed drill), Reduced tillage (3 harrowing fb planking) and Conventional tillage (6-7 harrowing fb planking) in main plots and seven weed management practices (i.) Isoproturon 1.0 kg ha^-1 at 30 DAS (ii.) Clodinafop – propargyl 60 g ha^-1 at 30 DAS (iii). Metsulfuron methyl 4 g ha^-1 at 30 DAS (iv) Isoproturon 1.0 kg ha^-1 + Metsulfuron methyl 4 g ha^-1 at 30 DAS (v) Clodinafop – Propargyl 60 g ha^-1 at 30 DAS fb. Metsulfuron methyl 4 g ha^-1 at 37 DAS  (vi) Hand weeding at 30 & 50 DAS (vii). Weedy (control)  in sub plots, replicated thrice in a split plot design.  The relative contribution of grasses to total weed population in terms of density was higher at all the stages of crop growth. Phalaris minor was the most dominant weed at 60 DAS contributed 55.0 per cent of total weed population. Melilotus indica was the major non grassy weeds in wheat which contributed 11 per cent to total weed population during respective years. Density of total weeds recorded lower under zero tillage as compared to the conventional tillage. Reduced tillage also recorded lower weed density than conventional tillage but it was higher than zero tillage. Sowing of wheat with zero tillage significantly reduced the Phalaris minor density as compared to conventionally tilled wheat after transplanted rice, 60 per cent Phalaris minor emerged from 0-3 cm in reduced and conventional tillage where as in zero tillage after transplanted rice there was 55 per cent emergence from 0-3 cm layer. The weed density and dry matter of all the individual weeds were recorded higher in conventional tillage as compared to zero tillage at 60 DAS, except Rumex acetosella and Medicago denticulate. The zero tilled wheat yielded 12.35 and 3.66 per cent higher over reduced and conventional tillage during Ist year and 11.99 and 3.09 per cent during IInd year. The straw yield was higher under zero tillage and increase of 9.7 and 9.95 per cent over reduced tillage and 2.52 and 2.69 per cent over conventional tillage during Ist year and IInd year, respectively. The highest grain yield was obtained in two hand weedings done at 30 and 60 DAS and was at par with Isoproturon 1.0 kg ha^-1 + Metsulfuron methyl 4 g ha^-1 at 30 DAS and Clodinafop – Propargyl 60 g ha^-1 at 30 DAS fb. Metsulfuron methyl 4 g ha^-1 at 37 DAS. Uncontrolled weeds on an average caused 62.0 and 65.7 per cent reduction in the yield during Ist year and IInd year, respectively as compared to crop given two hand weeding at 30 and 50 DAS. The bulk density of the soil was not affected by different weed management practices in wheat. Zero tillage resulted in significantly higher uptake of NPK by wheat plants as compared to conventional tillage, whereas reduced tillage recorded minimum NPK, which was significantly lower over the other treatments of wheat establishment methods. The maximum uptake of nutrients was observed under two hand weeding done at 30 and 50 DAS which was significantly higher than Isoproturon 1.0 kg ha^-1 + Metsulfuron methyl 4 g ha^-1 at 30 DAS and Clodinafop – Propargyl 60 g ha^-1 at 30 DAS fb. Metsulfuron methyl 4 g ha^-1 at 37 DAS