Novel method to manage weeds in the rainfed groundnut (var. VRI 8 and TMV 14) using nano encapsulated herbicide formulations

The groundnut crop harbours heavy weed infestation due to its small stature and slow growing nature. The current weed management practices of hand weeding and use of commercial herbicides are unsuitable because of high labour cost and inadequate moisture availability to activate herbicides.  In order to release the herbicide in a smart way, this experiment aimed to study the efficacy of encapsulated herbicides . Field experiments were conducted during Kharif 2021 and late Rabi 2022 under rainfed conditions in randomised block design with three replications. The treatments consisted of sulfentrazone, oxyfluorfen, diclosulam and metolachlor in both commercial and encapsulated form using two doses, hand weeding at 20 and 40 DAS, weed free plot and weedy check. Minimum weed density (28.33 and 17.30 No./m2 at 90 DAS during Kharif and late Rabi respectively) and weed dry weight (65.33 and 61.25 g/m2 at 90 DAS during Kharif and late Rabi respectively) were observed in hand weeding at 20 and 40 DAS (T19) followed by diclosulam @ 25 g ha-1 with encapsulation (T7). Maximum weed density and weed dry weight was observed in metolachlor @ 1 kg/ha with encapsulation (T8). Higher productivity was observed in hand weeding at 20 and 40 DAS (T19) (1802 kg ha-1  and 1753 kg ha-1  pod yield during Kharif and late Rabi respectively) and higher profitability was obtained in diclosulam @ 25 g ha-1 with encapsulation (T7) (1.80 and 2.01 B:C ratio during (Kharif and late Rabi respectively). Nano-encapsulated herbicides can thus significantly improve weed control in rainfed groundnut.