Split application of nutrients through fertigation in Bt cotton

Field experiment was conducted during from 2008-2010 on medium clay soil at Research Farm of Mahatma Phule Agricultural University, Rahuri to find out the response of drip fertigation on growth, yield and economics of Bt cotton(Gossypium hirsutum L.). Pooled data indicated that drip resulted into 24.7 per cent increase in yield with 56.9 per cent water saving, whereas drip with fertigation resulted into 31.7 to 64 per cent increase in seed cotton yield with equal amount of water saving as compared to conventional method. The maximum seed cotton yield (45.33 q/ha) was recorded with 125 per cent fertigation schedule B. However, it was on par with 100 per cent (schedule B), 100 per cent (schedule C) and 75 per cent fertigation (schedule B). The seed cotton yield (39.07 q/ha) obtained under 75 per cent fertigation was on par with treatment where100 per cent conventional fertilizer applied through soil (34.59 q/ha) indicating 25 per cent fertilizer saving due to fertigation. Maximum water use efficiency (14.22 q/ha-mm) was obtained where 125 per cent water soluble fertilizer applied through drip. Economic analysis of drip irrigation and fertigation revealed that the cost of cultivation under drip with band application of fertilizers and drip fertigation was higher than conventional band application. However, the highest net income (Rs. 131381.2/ha), total net income (Rs. 307273.4), and net extra income over conventional method (Rs. 61030.6/ha) were realized in 125 per cent fertigation, but it were on par with the economical parameters obtained in 100 and 75per cent fertigation. The benefit cost ratio was lowest in drip fertigation and drip band application mainly due to higher initial investment for drip irrigation and high cost of water soluble fertilizers.