The Effects Of Nitrogen Application Strategy On Soil Environment And Biological Characteristics Of Cotton In Arid Land

This study forcused on the different nitrogen application strategies on soil environment and biological characteristics of cotton in the same total quantity of nitrogen at each growth stage of dressing cases which done at the typical arid area in Xinjiang Korla cotton, for 1-year field experiment to. The results are as follows:(1)There were significant differences in the single stub boll's quantity and the cotton yield, because of different nitrogen application strategies.The yield 6782kg·hm-2 is the highest which the proportion of nitrogen is5.96%,4.47%,18.63%,16.4%,4.47%,9.69%.(2)At the same nitrogen application strategy,the proportion of nitrogen on3.73%,6.71%,15.28%,19.75%,12.3%,1.86% and the proportion of nitrogen on5.96%,4.47%,18.63%,16.4%,4.47%,9.69% treatments are low soil water quantity and low soil conductivity under low irrigation quantity,the proportion of nitrogen on 4.47%,5.96%,16.4%,18.63%,9.69%,4.47% treatment is low soil water quantity and low conductivity under high irrigation, but the soil water quantity,and the soil conductivity were no significant change which the proportion of nitrogen on5.22%,5.22%,23.5%,23.5%,9.5%,9.5% treatment under two irrigation.(3)At the same nitrogen application strategy,the soil water quantity increased with the soil depth in 0～60cm, when the soil conductivity value went down with the soil depth.(4)At the full growing period,the variety trend peak and the accumulation of chlorophyll SPAD value were different under different strategies of nitrogen application.The trend of leaf area are presented single peak curve,the peak value is presented in flowerring stage,the diversity of leaf area are remarkable under water-nitrogen coupling.The dynamic curve of dry matter accumulation of the process can be imitated by the curve of Logistic expression,the dry matter accumulation is the highest which the proportion of nitrogen is5.96%,4.47%,18.63%,16.4%,4.47%,9.69%.(5)There were significant negative correlation between the soil conductivity value and water quantity, soil depth, the significant positive correlation between soil conductivity value and illumination. At the same time,there were significant correlation between the water quantity and soil depth, illumination.There were significant positive correlations between chlorophyll SPAD values,the leaf area, dry matter accumulation and yield.(6)On base of enough irrigation, the appropriate proportion nitrogen are: basal nitrogen(40%),the first nitrogen(in budding stage:5.63%～6%),the second nitrogen(in early flowerring stage:4.5%～4.97%),the third nitrogen(in flourish flowerring stage:16.38%～18.75%),the fouth nitrogen(in early boll stage:16.5%～18.87%),the fifth nitrogen(in boll stage:4.5%～8.36%),the sixth nitrogen(in boll stage: 5.89%～9.75%).