Effect of herbicide mixture and mechanical weeding on weed dynamics and yield of kharif groundnut

Abstract

Groundnut (Arachis hypogaea L.) is the major oilseed crop in India and it plays a major role in bridging the vegetable oil deficit in the country. Weed infestation poses a significant challenge and is a serious problem in reducing the productivity of groundnut. The sole application of herbicides is unable to control the later germinating weeds; hence, to mitigate the weed-related losses and increase the yield, an integrated weed management strategy needs to be studied. In view of the above, the present investigation was planned to evaluate the “effect of herbicide mixture and mechanical weeding on weed dynamics and yield of kharif groundnut”. The field experiment was conducted in the loamy sand soil of All India Coordinated Research Project on Weed Management (AICRP) on Weed Management Farm, B. A. College of Agriculture, Anand Agricultural University, Anand, during three consecutive kharif seasons of 2022–24. The experiment was laid out in a randomised block design (RBD) with three replications. The treatments included T1: Pendimethalin 30 % emulsifiable concentrate (EC) 750 g active ingredient per hectare (a.i./ha),  T2: Flumioxazin 50 % suspension concentrate (SC) 125 g a.i./ha, T3: Diclosulam 84 % water dispersible granules (WDG) 25.2 g a.i./ha,   T4: Oxyfluorfen 23.5 % EC + pendimethalin 30 % EC (tank mix) 188 + 500 g a.i./ha,  T5: Diclosulam 84 % WDG + pendimethalin 30 % EC (tank mix) 25.2 + 500 g  a.i./ha, T6: Pendimethalin 30 % +  imazethapyr 2 % EC (ready mix (RM)) 800 g a.i./ha, T7: Sodium acifluorfen 16.5 %  +  clodinafop propargyl 8 % EC  (RM) 245 g a.i./ha, T8: Fluazifop-p-butyl 11.1 % w/w  +  fomesafen 11.1 % w/w soluble concentrate (SL) (RM) 250 g a.i./ha, T9: Propaquizafop 2.5 %  +  imazethapyr 3.75 % w/w micro-emulsion (ME)  (RM)  125 g a.i./ha, T10: Quizalofop ethyl 7.5 %  +  imazethapyr 15 % w/w EC (RM) 90 g a.i./ha, T11: Intercultivation (IC) followed by hand weeding (HW) at 20 and 40 days after sowing (DAS) and T12: Weedy check. In treatments T₁–T₁₀, IC followed by HW at 40 DAS was carried out as a common practice. Results revealed that significantly lower density and dry biomass of weeds, weed index, higher weed control efficiency, shelling percentage, seed index, pod yield and benefit-to-cost ratio (B: C) were recorded in application of either diclosulam 25.2 g a.i./ha pre-emergence (PE) followed by IC + HW at 40 DAS or sodium acifluorfen + clodinafop propargyl 245 g a.i./ha post-emergence (PoE) followed by IC  +  HW at 40 DAS or fluazifop-p-butyl + fomesafen 250 g a.i./ha PoE followed by IC + HW at 40 DAS or propaquizafop  +  imazethapyr 125 g a.i./ha PoE followed by IC + HW at 40 DAS or IC followed by HW at 20 and 40 DAS. Residue of all the applied herbicides in groundnut mature pods, stover and in soil were found below the limit of quantification (LOQ) of 0.01 mg/kg at the time of harvest.