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| Effects of water, nitrogen and salt regulation on cotton yield under mulch film drip irrigation and its coupled model |
| ZHAI Zhongmin, SHI Wenjuan*, ZHANG Yanchao, GAO Zhiyong |
| State Key Laboratory of Eco-hyraulics in Northwest Arid Region in China, Xi′an University of Technology, Xi′an, Shaanxi 710048, China |
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Abstract In order to explore the comprehensive effects of water, salt and nitrogen on cotton growth, the optimal water and fertilizer system, four irrigation quotas(1 575, 2 100, 2 625, 3 150 m3/hm2), four nitrogen application rate(0, 150, 300, 450 kg/hm2)and four soil salinity(non-salinized soil, slightly saline soil, moderate salt chemical soil and heavily saline soil)were set respectively. The effects of water, nitrogen and salt on cotton yield under film drip irrigation were studied through pot experiment. The results show that the relationship between irrigation quota, nitrogen application rate, soil salt and cotton yield was in line with the regression model, and the model has a good coupling effect on the effects of water, nitrogen and salt on cotton. The effect of single factor on cotton yield is ranked as irrigation amount > soil salt content > nitrogen application amount. The influence order of two factors is the coupling effect of salt and nitrogen > the coupling effect of water and nitrogen > the coupling effect of water and salt. There is a threshold value for the effects of water and nitrogen application on cotton yield, below which the cotton yield increase effect is obvious. The cotton growth is inhibited obviously under medium and severe soil salt content. The most suitable system of water, fertilizer and salt in the study area is determined by the regression model, which is light salt soil, irrigation quota 2 677 m3/hm2 and nitrogen application rate 202 kg/hm2. This study will provide a scientific basis for the efficient utilization of water and fertilizer in drip irrigation cotton field under film in saline-alkali area.
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Received: 20 August 2020
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