Effect of irrigation and weed management practices on Nutrient uptake and Economics of production of Aerobic rice

In a study conducted during 2007 and 2008 on irrigation and weed management effect on aerobic rice, scheduling the irrigation with IW/CPE of 1.2 produced significantly higher stature of yield attributes viz., total number of panicles m -2 , total number of grains and number of filled grains and grain (4702 and 4547 kg ha -1 ) and straw yield and were distinctly superior to IW/CPE of 0.8 and 1.0. The nutrient uptake (nitrogen, phosphorus and potassium) by crop was also significantly highest with IW/CPE of 1.2.Weed management practices exerted significant influence on yield attributes, yield (5761 and 5595 kg ha -1 ), nutrient uptake by crop and all of them were at their highest with hand weeding at 20 and 40 days, which were comparable with oxadiargyl 0.07 kg ai ha -1 supplemented with hand weeding at 40 days. All the yield attributes and yield of rice were the lowest with unweeded check. Nutrient uptake by weeds was significantly highest with IW/CPE of 1.0 and among weed management practices with hand weeding at 20 and 40 days. Highest returns and benefit-cost ratio were recorded with the irrigations scheduled at IW/CPE ratio of 1.2 and with pre emergence application of oxadiargyl 0.07 kg ai ha -1 supplemented with hand weeding at 40 days.