Bio-efficacy of readi-mix herbicides on weeds and productivity in late-sown wheat

A field experiment was conducted during 2015–16 and 2016–17 at Rajasthan College of Agriculture, Udaipur, India to evaluate the bio-efficacy of readi-mix herbicides in late sown wheat. The experiment consisting of fifteen treatments was laid out in randomized block design with four replications. The results revealed that Readi-mix application of sulfosulfuron + metsulfuron (32 g/ha)) and mesosulfuron + iodosulfuron (14.4 g/ha) gave higher weed control index (95.36, 94.72%), lower weed index (2.00, 2.75%) and weed persistence index (0.349, 0.351) whereas, higher index value of crop resistance index (CRI), weed management index (WMI) and herbicide efficiency index (HEI) (28.61, 0.38 and 5.50). Both of these treatments recorded 34.3 and 33.3 per cent grain yield enhancement along with 49.0% and 47.7% higher net returns over the unweeded control with the highest benefit-cost ratio (2.34 and 2.32). Results from contract analysis indicated significant (p < 0.0001) interaction of year × treatments and response of Readi-mix v/s single/sequential herbicide application on grain yield, weed density and dry matter. The joint effect of parameters on grain yield was significant with high magnitude (R_{GYWeed density total, Weed dry weight total, Total N, P and K uptake} = 0.98; p < 0.0001). Additionally, the regression model for grain yield on total weed density (R² = 0.84), weed dry weight (R²=0.79), total N uptake (R²=0.98), P uptake (R²=0.93) and K uptake (R² = 0.97) demonstrated significant dependence. Moreover, no symptoms of phytotoxicity were seen in any of the treatment in the crop at 21 days after herbicide application.