Drip fertigation improves seed cotton yield, water productivity and profitability of cotton raised under high density planting system in semi-arid environment

The wasteful system of flood irrigation being widely practiced for cotton production in India needs replacement by efficient irrigation systems for conserving water. Cotton productivity can be boosted by optimizing the nutrient and water application through modern resource conservation techniques. Therefore, a field experiment has been conducted during summer (Kharif) season of year 2016 and 2017 to investigate consequence of surface drip irrigation along with N fertilization on the growth and seed cotton yield (SCY) under recently introduced high density planting system (HDPS) in India. The experiment having combinations of 3 drip irrigation {60, 80 and 100% of crop evapo-transpiration (ETc)} and 3 N fertigation levels {125 (94 kg N), 100 (75 kg N) and 75% (56 kg N) of recommended N dose (RDN)} along with control (i.e. conventional practice of irrigation through surface flood and soil broadcasting of urea as  100% RDN i.e., 75 kg N ha-1) has been conducted in complete randomized block design replicated thrice. Drip irrigation scheduled at 0.8 ETc recorded 2.5 and 23.2% higher SCY (2509 kg ha-1) than 1.0 ETc and 0.6 ETc, respectively. Among N levels, highest SCY (2452 kg) was observed with 75 kg N application, whereas 56 kg N ha-1 recorded least. A combination of drip fertigation at 0.8 ETc and 100% RDN elucidated 11.6, 61.5, 13.9 %, and 42.9 % higher SCY, water use efficiency, nitrogen use efficiency and benefit: cost ratio than control, respectively. Drip fertigation at 1.0 ETc along with 100% RDN improved SCY by 7.3% over control.