Functions of Cotton Yield Response to Soil Salinity in Akesu River Irrigation District

Abstract

Based on experimental data from the five observation points during the three years, the linear subsected functions and the nonlinear s-shaped functions between the cotton relative yield and soil salt content on the salinized soil about the 0-20cm soil layer and the 0-40cm soil layer in Akesu River Irrigation District were constructed by linear regression and nonlinear least square approximation. Their applicabilities were analyzed and compared and it was found the nonlinear s-shaped function of the 0-20cm soil layer to fit better with the response relationship between the cotton relative yield and the soil salt content on the salinity soil than others in Akesu River Irrigation District.which and the indexes of cotton salt tolerance were definited, and then the indexes of cotton salt tolerance were drawn on with the function with better applicability. From the function, some indexes of salt tolerance，which contained the cotton critical soil salt content, the cotton threshold soil salt content, the soil salt content at the fastest rate of cotton relative yield reduction, and the soil salt content at the 50% cotton relative yield reduction, and so on, were determined, which can be provide as the important references for the agricultural planting, improvement of salinized soil and irrigation with saline water in Akesu River Irrigation District.