Weed suppression and crop yield in wheat after mustard seed meal aqueous extract application with reduced rate of isoproturon

Abstract Weeds are the major biological constraints to wheat production, which reduces the wheat yield up to 80%. The phytotoxic effect of brassica water extracts against weeds has been previously studied; however, the effects of mustard seed meal water extract (MSMWE) alone or in combination with reduced rate of isoproturon (IP) have not yet been explored. Hence, a field experiment was conducted in randomized complete block design to investigate the efficacy of MSMWE, at variable rates, i.e., 113, 225, 338, and 450 L ha−1 alone or combined with IP at 0.50 kg a.i. ha−1 (POST) (IP 0.5), and compared with the recommended rate of IP at 1.0 kg a.i. ha−1 (POST) (IP 1.0), weedy control, and twice-hand weeding (2-HW). Results revealed that 2-HW was the best treatment for weed suppression and wheat yield. Overall, MSMWE 450 L ha−1 + IP 0.5 was highly effective in the suppression of broadleaved weeds (BLWs) as well as of total weeds, and recorded the highest weed control efficiency (47.67) and herbicide efficiency index (0.927). Further, this treatment positively enhanced the tiller count, grain count earhead−1 and grain yield. Application of IP 1.0 effectively suppressed the BLWs, however, failed in the suppression of grassy weeds and total weeds; further, it showed a negative influence on crop dry matter accumulation and grain yield. Sole application of MSMWE suppressed the grassy weeds, dominated by Cynodon dactylon, as compared to combined and sole application of IP. Here we show for the first time that sole MSMWE has potential for suppression of C. dactylon.