Phytotoxic Effect and the Efficiency of Different Herbicides and Nitrogen Levels on Weed Control in Wheat Crop

A field experiment was carried out during the winter (rabi) season of 2018–19 at the Agricultural Research Farm, Banaras Hindu University, Varanasi, to evaluate the impact of herbicides and nitrogen levels on phytotoxic effect and the efficiency of different herbicides and nitrogen levels in wheat. The wheat field was infested with nine weed species such as Phalaris minor, Cynodon dactylon, Anagallis arvensis, Melilotus indicus, Chenopodium album, Vicia sativa, Medicago denticulata, Solanum nigrum, and Cyperus rotundus. Among these, Cyperus rotundus and Cynodon dactylon were the major weeds. Visual phytotoxicity indicated that phytotoxicity was observed under pinoxaden (40 ml ha-1) + 2, 4-DEE (750 ml ha-1). The data pertaining to available N, P2O5, K2O in soil after harvest of crop revealed that application of herbicides and nitrogen levels observed non-significant differences except higher available K2O in soil observed by application of pinoxaden 5.1%EC + 2,4- DEE 38%EC (40+750 ml ha-1) significantly over weedy check and statistically at par with rest of the treatments. Further, higher weed management index (WMI) was recorded under HW twice plot (30&60 DAS) was 0.13 followed by under application of sulfosulfuron (25 g ha-1) + 2, 4-DEE (750 ml ha-1) was 0.11. Weed density and biomass had strong negative correlation with grain yield (r = -0.39 and r = -0.40, respectively). The interaction effect of highest grain and straw yields were achieved with the application of Sulfosulfuron (25 g ha⁻¹) + 2,4-DEE (750 ml ha⁻¹) in combination with 180 kg N ha⁻¹.