Research Of Cotton Nitrogen Integrated Management Under Drip Irrigation And Plastic Film Mulch

This paper is focused on optimal N management in cotton cultivation under drip irrigation and film mulch condition.4 field experiments were designed to test N application and cotton yield response, fertilization pattern or irrigation frequency change and cotton yield response and, some N nutrition diagnosis and N recommendation methods were compared in this research. Main results are as follows:(1) Nitrogen fertilizer application rates showed a typical quadric curve with seed cotton yield, with the increasing of N rate in a certain range, seed cotton yield showed increase with depression trend, as cotton yield reach a peak point, the seed cotton yield decrease with the increase of N application. Fertilizer response function showed that In this experiment, the highest seed cotton yield was 7259.78 kg/hm2, correspond nitrogen fertilizer was N 345.06 kg/hm2. Cotton optimum economic nitrogen fertilization rate was 236.85 kg/hm2, correspond cotton yield was 7079.43 kg/hm2.(2) Adjustment fertilization patterns showed that compared with the conventional irrigation management, there were no significantly difference in dry matter of cotton plant, N uptake, yield and yield structure of the adjustment irrigation management. But there were significantly differences of nitrate residue in the soil profile, soil nitrate content increased in subsoil if solo irrigation and then fertilization pattern were adopted.(3) Different irrigation frequency experiment showed that high-frequency irrigation in boll stage can increase nitrogen absorption of cotton and nitrogen use efficiency, increase cotton yield and dry matter, while reducing the amount of residual nitrate in soil.(4) some N nutrition diagnosis and N recommendation methods showed that compared with fanner's conventional fertilization practice (FP), N recommendation based on computer vision (Ncv) method reduced N application by 37.8% and N recommendation based on Nmin reduced N application by 56.3%. N recovery rate (NUE) of Nmin and Ncv were significantly higher as compared to FP, increased by 27.80% and 16.96%, respectively. Nitrate residues in soil profile increased dramatically with the increase of nitrogen fertilizer dosage, Nmin and Ncv reduced the amount of fertilization, thus significantly reduced the residual nitrate in the soil. Apparent N losses amount was significantly lower than FP patterns, indicating that both Ncv and Nmin methods help to achieve nitrogen balance and prevent access input of nitrogen fertilizer, and reduce greenhouse gased emissions to the environment.(5) As a widely used nitrogen fertilizer recommendation tools, Nmin suitable for nitrogen management in the Xinjiang cotton production. N recommendation based on computer vision technology performance a good nitrogen management effects, while with fast and low-cost advantages, is suitable as an alternative means of Nmin.