| The coupling effect of water and nitrogen on cotton yield and water use efficiency (WUE) was studied under different drip irrigation patterns.The field experiments were conducted in three drip irrigation patterns including 1 pipe 4 lines, 2 pipes 4 lines and 2 pipes 6 lines, in which universal design of the second rotation was used.The result showed that the coupling effect of water and nitrogen on cotton yield was more significant than nitrogen under three drip irrigation.In applying water of 65.1～284.9 mm, three drip irrigation patterns were positive correlation between cotton yield and water.In the applying nitrogen of 27.6～94.2 kg/hm2, 1 pipe-4 lines were positive correlation between nitrogen and cotton yield, 2 pipes-4 lines negative correlation in applying nitrogen of 27.6～69.0 kg/hm2 and positive correlation in the applying nitrogen of 69～94.2 kg/hm2, 2 pipes-6 lines positive correlation in applying nitrogen of 27.6～55.2 kg/hm2 and negative correlation in applying nitrogen of 55.2～94.2 kg/hm2.For the coupling effect of water and nitrogen on water use efficiency (WUE) , water was more significant than nitrogen under three drip irrigation patterns.1 pipe4 lines was positive correlation between nitrogen and WUE.2 pipes-4 lines was negative correlation in applying nitrogen of 27.2～44.4 kg/hm2 and positive correlation in applying nitrogen of 44.2～94.2 kg/hm2, 2 pipes-6 lines was positive correlation in applying nitrogen of 27.6～55.2 kg/hm2 and negative correlation in applying nitrogen of 55.2～94.2 kg/hm2.In applying water of 65.1～284.9 mm, three drip irrigation patterns were negative correlation between water and WUE.According to water and nitrogen coupling effect in different patterns of drip irrigation, a management strategy was set forward with increasing cotton yield and WUE as the objectives. |