Selectivity of new generation herbicide ‘Tembotrione’ under conservation agriculture-based maize (Zea mays) in maize-wheat-mungbean cropping system

An experiment was conducted at the ICAR-Indian Agricultural Research Institute in New Delhi during the rainy (Kharif) seasons of 2021–22 and 2022–23. The study aimed to evaluate the weed control efficiency of low dose new generation herbicide: tembotrione (34.4% SC) as a component of integrated weed management (IWM), on zero-till (ZT) and conventional till (CT) maize (Zea mays L.). The treatments were comprised of conventional tillage maize (M1: CT-M), conventional tillage maize with green manure from preceding green gram (M2: CT-M+GM), zero tillage maize with residue retention at 3 t/ha (M3: ZT-M+R), zero tillage maize with Sesbania co-culture as brown manuring (cover crop) (M4: ZT-M+BM) in the main plot and five weed control treatments, viz S1: Un- weeded check, S2: Pre +1 HW, S3: Pre + Post (tembotrione) @120g/ha, S4: Pre+ Post (Premix of Mesotrione+ Atrazine) @120 g/ha, S5: Weed free check (WFC) in the sub-plots were evaluated in split-plot design. It was ob- served that ZT-M+BM caused a considerable reduction in the population of broad-leaf weed, narrow leaf weed with sedges and total weeds (28.4% reduction at 60 days after sowing) compared to M1. The results also revealed that the sequential application of atrazine @750g/ha+pendimethalin @750g/ha(pre) followed by (fb.) tembotrione (34.4% SC) @120 g/ha (post) among the herbicide options reduced the weeds population (78.5%) and dry weight (81.3%) significantly than the un-weeded control (UWC). Maize yield attributes were higher in ZT with Sesbania co-culture (ZT-M+BM) than conventional-tilled treatments (CT-M). The application of atrazine @750g/ ha+pendimethalin @750g/ha (pre) fb. tembotrione @120 g/ha (post) combined with ZT-M+BM resulting in higher maize yield (6.88 t/ha) which was comparable with that in weed-free check (WFC). The post emergence (PoE) ap- plication of tembotrione (34.4% SC) @120 g/ha recorded highest weed control efficiency (86.2%), weed control in- dex (88.1%) and lowest value of weed index (7.04) when applied in the ZT-maize with sesbania as a cover crop. Therefore, combining zero tillage (ZT) with brown manure (Sesbania), along with atrazine and pendimethalin (@750g/ha each) as pre-emergence herbicides, and tembotrione (@120g/ha) as a post-emergence herbicide is recommended for effective weed control and high maize productivity in the North-Western Indo-Gangetic plains (IGP).