Effect of Quantity of Irrigation on the Efficacy of Isoproturon against Phalaris minor in Wheat

Field studies carried out at the Punjab Agricultural University, Ludhiana, during 1993–94 and 1994–95 revealed that heavier first irrigation (10 cm) resulted in 18.2% reduction in weed control efficiency of isoproturon 0.94 kg/ha applied three days before first irrigation, compared to normal irrigation (7 cm). Heavy first irrigation also depressed wheat yield and its contributing characters, resulting in 46.48 q/ha grain yield as compared to 51.02 q/ha under normal irrigation. Application of higher dose of isoproturon (1.13 kg/ha) compensated the adverse effect of heavier first irrigation. Variable quantity of second irrigation after the application of isoproturon did not show marked effect on weE and grain yield of wheat when the herbicide was applied six days after nonnal first irrigation of 7.0 cm.