Influence of weed management methods on weed characteristics, yield and economics of machine-transplanted rice

A field experiment was conducted at Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu during late Samba (Oct-Feb) season of 2017–18 to assess the weed characteristics in relation to yield under machine-transplanted rice. The experiment included eight treatments viz T₁: Unweeded check, T₂: Pretilachlor [pre-emergence (PE)] followed by hand weeding 20 days after treatment (DAT), T₃: Pretilachlor (PE) followed by metsulfuron methyl + chlorimuron methyl [post-emergence (POE)] 20 DAT, T₄: Pretilachlor (PE) followed by weeding with power weeder 20 DAT, T₅: Pretilachlor (PE) followed by weeding with power weeder 20 and 35 DAT, T₆: Pretilachlor (PE) followed by weeding with power weeder 20, 30 and 40 DAT, T₇: Weeding with power weeder 20 and 35 DAT and T₈: Weeding with power weeder 20, 30 and 40 DAT. The field trial was designed in randomised complete block design and replicated three times. The results revealed that application of pretilachlor (PE) followed by either hand weeding on 20 DAT (T₂) or with power weeding twice (T₅) or thrice (T₆) or with chemical combinations of pre-emergence and post-emergence (T₃) registered lesser weed dry weight, lower weed density with higher weed control efficiency that led to higher grain yield, straw yield and B-C ratio in rice.