HERBICIDES, THEIR APPLICATION TIMINGS AND DIFFERENT SOIL TEMPERATURE REGIMES AFFECT WEED INFESTATION IN WHEAT

Soil temperature, herbicides and their application timings were studied to determine their effect on weed infestation in wheat during 2012-13. a randomized complete block design (rcbd) with split plot arrangement was used to layout the experiment where herbicide application timings viz; t1: 30 days after sowing (das) and 40 das (t2) were randomized in main plot whereas weedy check (w0), weed free (w1), affinity 50 wp (carfentrazone + isoproturan) (w2) and axial 0.50 ec (pinoxaden) + buctril super 60 ec (bromoxynil + mcpa) (w3) were kept in sub-plots, respectively. results showed that herbicides reduced weed density and its dry weight considerably in contrast to weedy check. moreover, axial 0.50 ec (pinoxaden) + buctril super 60 ec (bromoxynil + mcpa) was found most effective regarding weed control. overall, chemical weed control led to substantial reduction in weed infestation in wheat. however, yield and yield related attributes like fertile tillers m-2, spikelets per spike, grains per spike, 1000-grain weight, grain yield and harvest index were improved so far in weed control treatments as compared to weedy check whereas soil temperature pertaining to weed emergence rate was recorded as: 6-8 ºc > 8-10 ºc > 10-12ºc.