Study On Nitrogen Nutrient Real Time Monitoring And Nitrogen Fertilizer Recommendation Techniques Based On Soil Nmin In Cotton Field

Object: Cotton growth has become esential part of agriculture economy in XinJiang these days, Nitrogen fertilizer contribute to this development a lot. Optimized nitrogen management in cotton farmland is the only way to promote the economic performance, lower the environment impect and for rural development. Based on field experiment, demonstration and application, Nitrogen nutrient real-time monitoring and nitrogen fertilizer recommendation techniques based on soil Nmin in cotton field was put forward, combined with computer vision identification techniques, for the proposal of providing theoretic basis for precise fertilizer applicationand nutrient management in cotton cultivation.Methods: Based on field experiment, Nitrogen nutrient real time monitoring and nitrogen fertilizer recommendation techniques based on soil Nmin in cotton field was founded, combined with analysis and identification techniques of digital picture. the technique was validated by means of field demonstration.Results: Optimized nitrogen management experiment on cotton in Wulanwushu meteorologic station, demonstration an application in 147 farm, 150 farm and Wulanwushu meteorologic station were completed from 2005 to 2007.Conclusion:1. Dry matter, N uptake of cotton plant and soil nitrogen mineralization could be modeled by Logistic model, with high coefficient of determination (r= 0.9508-0.9990).2. Compared with the conventional management, there were no significantly difference in dry matter of cotton plant, N uptake, yield and yield structure of the 100% optimized nitrogen management based on soil Nmin. 100% optimized N treatments dramatically reduced N fertilizer application amount from 21% to 33%.3. Nitrogen input-output budget of cotton-soil system at different nitrogen treatment showed that N splus of Con, 140%, 180% N treatments increased to 380 kg/hm2, Nmin and apparent losses increased to 187 kg/hm~2 and 193 kg/hm~2 after harvest.4. Optimized N supply were 250.5,270.5 and 293.5 kg/hm~2 according to the rates of Nmin supply based on 0-20,0-40,0-60 cm soil profiles. Accumulation of Nmin and rates of N supplied at different soil layers increased by soil depth. 5. A computer program was developed based on computer vision and soil Nmin dynamic model, plus cotton plant N requirement aim at different lint yield. The program was named ImageExp1.0. Field evaluation demonstrated that with assistance of ImageExp1.0, N fertilizer application decreased from 25% to 60%, with a yield increase by 5%-12%.