Fraction of intercepted radiation of cotton responds to irrigation and integrated plant nutrition

Significant effect of different irrigation schedules and integrated nutrition levels was determined on fraction of intercepted radiation (Fi) in cotton. The treatments were four irrigation schedules viz. six irrigations (I/sub 1/), three irrigations (I/sub 2/), irrigation at 25 mm deficit (I/sub 3/) and irrigation at 50 mm deficit (I/sub 4/ ), and seven integrated nutrition levels i.e. control (N/sub 0/), 75-37.5-37.5 kg NPK ha/sup -1/ (N/sub 1/), 75-37.5-37.5 kg NPK ha/sup -1/ + FYM (farm yard manure) at the rate of 20 t ha/sup -1/ (N/sub 2/),75-37.5-37.5 kg NPK ha /sub -1/ + wheat straw at the rate of 5 t ha/sup -1/ (N/sub 3/), 150-75-75 kg NPK ha/sup -1/ (N/sub 4/), 150-75-75 kg NPK ha/sup -1/ + FYM at the rate of 20 t ha/sup -1/ (N/sub 5/), 150-75-75 kg NPK ha/sub -1/ + wheat straw at the rate of 5 t ha/sub -1/(N/sub 6/). Positive and linear relationships were established between Fi and total dry matter (TDM); and Fi and seed cotton yield. Significantly higher Fi values were attained when the crop was planted at N/sub 5/ with any of three irrigation schedules viz. I/sub 1/ or I/sub 3/ or I/sub 4/. The highest values of Fi (0.914 in first year and 0.913 in second year of study) were recorded with I/sub 4/N/sub 5/ which were followed by I/sub 3/ N/sub 5/ and I/sub 1/ N/sub 5/. The interactions I/sub 4/ N/sub 5/, I/sub 3/ N/sub 5/ and I/sub 1/N/sub 5/ harvested 23.51, 23.38 and 20.27 % greater Fi to I/sub 2/ N/sub 0/. (author)