Optimum irrigation and integrated nutrition improves the crop growth and net assimilation rate of cotton (Gossypum hirsutum L.)

The objective was to find out the impact of different irrigation schedules and integrated plant nutrition levels on the seasonal crop growth rate (cgr) and net assimilation rate (nar) of cotton. the experiments were conducted using rcbd with split plot arrangement. the treatments were four irrigation schedules (main plot) i.e. six irrigations (i1),three irrigations (i2),irrigation at 25 mm deficit (i3) and irrigation at 50 mm deficit (i4),and seven integrated nutrition levels (sub plot) viz. control (n0),75-37.5-37.5 kg n-p2o5-k2o ha-1 (n1),75-37.5-37.5 kg n-p2o5-k2o ha-1 + fym @ 20 t ha-1 (n2),75-37.5-37.5 kg n-p2o5-k2o ha-1 + wheat straw @ 5 t ha-1 (n3),150-75-75 kg np2o5- k2o ha-1 (n4),150-75-75 kg n-p2o5-k2o ha-1 + fym @ 20 t ha-1 (n5),150-75-75 kg np2o5- k2o ha-1 + wheat straw @ 5 t ha-1 (n6). significantly higher seasonal cgr and nar were attained at n5 with any of two irrigation schedules viz.,i3 or i4. interaction i3n5 increased cgr and nar by 145% and 20% in 2003 and 146% and 18%,respectively in 2004,however,i4n5 performed at par with i3n5 in 2003. linear relationships between cgr and seed cotton yield; and nar and yield were drawn. subsequently,i3n5 and i4n5 resulted in better performance and higher seed cotton yield.