Research Of Cotton Irrigation Mode In Xinjiang Cotton Drip Irrigation Based On Soil Water Potential

In order to analyze the dynamic changes of soil and calibrate soil water retention characteristics, based on the relationship between soil relative water content and soil water retention characteristics, these will provide a scientific basis of reasonable cotton irrigation system by determining the soil moisture. In this study, according to the local irrigation situation soil water potential was tested by negative pressure meter and soil water retention characteristics at0-20cm and20-40cm were calibrated. Soil water potential of the different depth soil was transformed soil relative water content through the equation of soil water retention characteristics curve, and guide the local irrigation. Below are the main results in this paper.1. the soil water potential and dry density at the depth of0-60cm were monitored using the depressimete on the Shihezi cotton area the result has shown that the121th Farming&Herding Regiment soil dry density had a significant changes at the0-40cm depth and no significant changes at the40-60cm depth. Therefore, Cotton cultivation and irrigation would affect significantly the soil of0-40cm depth. The soil water potential was real-time monitored though soil water potential monitoring system and soil water potential value was transformed soil relative water content by the equation of soil water retention characteristics curve, which can directly determine the soil moisture.2. Cotton yield had significant changed at the different irrigation condition in the various stages of cotton. The upper and lower irrigation threshold was65%and55%at the seeding stage, respectively. And the bud stage was75%and65%, blooming stage was85%and60%and the wadding stage was70%and50%. Overmuch irrigation had not only decreased cotton yield, but also accelerated water infiltration and decreased water use efficiency.3. Research of soil moisture monitoring had been finished and analyzed its design and function. Based on previous research, the upper and lower irrigation threshold had been ascertained at the various cotton stages. The different irrigation affected cotton yield to provide a scientific basis.4.In this paper, cotton yield of different irrigation has significant differences. Irrigation threshold had an important factor affecting cotton yield. There was negative relationship between irrigation value and boll weight. Drip irrigation quantity too little or too much decreased bolls per plant and decreased cotton yield.