Effect of Varied Irrigation Scheduling with Levels and Times of Nitrogen Application on Yield and Water Use Efficiency of Aerobic Rice

摘要

More rice needs to be produced with lesser water to feed the increasing human population. Judicious water management practices and appropriate water saving technologies in rice cultivation are in need in the coming decades. Aerobic rice is one of water saving method of rice cultivation. The field experiment was conducted during Summer season of February 2018 to May 2018 at Tamil Nadu Agricultural University, Agricultural College and Research Institute, Madurai, to find out the effect of irrigation schedules with varied doses and time of nitrogen application on yield of aerobic rice. Irrigation scheduling of IW/CPE (Irrigation Water/Cumulative Pan Evaporation) 1.0 up to panicle initiation stage and thereafter IW/CPE 1.2 up to dough stage recorded higher yield attributes viz ., number of panicles hill~(-1) (9.1), number of filled grains panicle~(-1) (87.9), test weight (15.3 g), grain yield (4462 kg·ha~(-1)), straw yield (5977 kg·ha~(-1)). However, the highest water use efficiency (6.8 kg·ha~(-1)·mm~(-1)) was recorded in the treatment of IW/CPE 1.0 throughout the crop growth period. Lower yield attributes, yield and water use efficiency were recorded with irrigation scheduling of IW/CPE 0.8 throughout the growth stage. Application of nitrogen at 150 kg·ha~(-1) in 5 equal splits at 20, 35, 50, 65 and 80 DAS (Days after sowing) recorded higher yield attributes viz ., number of panicles hill~(-1) (9.3), number of filled grains panicle~(-1) (90.5), test weight (15.4 g), grain yield (4746 kg·ha~(-1)), straw yield (6258 kg·ha~(-1)) and WUE (7.5 kg·ha~(-1)·mm~(-1)). Application of nitrogen 100 kg·ha~(-1) in 4 equal splits at 20, 40, 60 and 80 DAS recorded lower yield attributes, yield and water use efficiency. The interaction effect between irrigation scheduling and nitrogen management on yield was significant. The combination of IW/CPE 1.0 up to panicle initiation stage and thereafter IW/CPE 1.2 up to dough stage along with application of nitrogen at 150 kg·ha~(-1) in 5 equal splits at 20, 35, 50, 65 and 80 DAS significantly produced higher number of panicles hill~(-1) (10.7), grain yield of 5419 kg·ha~(-1) and straw yield of 6906 kg·ha~(-1). However, IW/CPE 1.0 throughout the growth period along with application of nitrogen at 150 kg·ha~(-1) in 5 equal splits at 20, 35, 50, 65 and 80 DAS registered the highest water use efficiency (8.4 kg·ha~(-1)·mm~(-1)) in aerobic rice.