Study on nitrogen fertilizer application techniques under membrane drip irrigation in cotton field in Bortala Mongolian Autonomous Prefecture.

[Objective]This study was carried out to discuss the suitable nitrogen fertilizer application techniques of the cotton field under membrane drip irrigation in Bortala Prefecture.[Method]According to the field experiment,a study was conducted on the nitrogen fertilizer application techniques in cotton field with the different texture and different fertility under drip irrigation.[Result]The economic optimum application rate of nitrogen is 540.4 kg/hm2 in the lower fertility cotton field under drip irrigation,and the economic optimum yield is 2 158.9 kg/hm2,the economic optimum application rate of nitrogen is 675.8 kg/hm2 in the higher fertility cotton field under drip irrigation,and the economic optimum yield is 2 236.5 kg/hm2;and adequate basal fertilizer application can enhance the yield with consistent condition of the nitrogen fertilizer rate,and it is better when 30% was used as the basal fertilizer,70% drip application was the best in the lower fertility sandy soil in cotton field under drip irrigation,according to the principle of slight in the earlier,heavy in the middle,supply in the later,and there is a significant effect on enhance boll weight,increase boll number and enhance yield when persist drip irrigation from budding stage stage to boll stage;The sustained drip application from budding stage to flower bolling stage can meet the demands of cotton growth in the soil with middle and high fertility.[Conclusion]It can gain higher yield and profit when application of urea is controlled within 525.0-560 kg/hm2 in cotton field under film drip irrigation.