Abstract:Soil salinity affects a range of physiological processes in the cotton fields and is key factor controlling cotton productivity and yield. Two-year experiments (2020 and 2021) were conducted to evaluate the effects of different leaching regimes on soil salinity, aboveground dry matter of cotton, and yield of seed cotton in Southern Xinjiang. There were four leaching amounts (W1: 75mm, W2: 150mm,W3: 225mm and W4: 300mm) and three leaching periods (T1: once at seedling period, T2: twice at seedling and budding periods and T3: thrice at seedling, budding and pollen setting periods) in addition to non-leaching treatment (CK: 85% crop evapotranspiration). During the experiment, soil salinity, aboveground dry matter accumulation, yield seed cotton and economic coefficient (ratio of yield to the total of dry matter accumulation and yield) were measured. The results showed that the leaching could leach the salinity in salinized cotton fields. Compared with the CK treatment, soil salinity in 0~100cm was decreased by 13.17% and 26.57% and the yield was increased by 104.13% and 59.36% in 2020 W4 and 2021 W3, respectively. The results of the Logistic equation to fit the dry matter accumulation were satisfactory (R2≥0.9654, P<0.05) for each treatment. Aboveground dry matter accumulation and seed cotton yield were positively correlated with leaching amount, and there was a difference between the economic coefficient and leaching amount under the same leaching period. The principal component analysis, technique for order preference by similarity to an ideal solution model (TOPSIS), gray correlation analysis and membership function analysis were well correlated with each other, and the correlation coefficients among the models were ranged from 0.92 to 0.99. Based on the overall difference combination evaluation model, the W4T2 treatment achieved the optimum. Further comprehensive analysis, considering the drought and low rainfall in the region, the results suggested that when leaching amount was 225mm and leaching periods at the seedling and budding stages during the reproductive period, the evaluations of comprehensive index (1.3765) was suitable for salinized cotton fields in the drip irrigation. The research result can provide valuable information for improving management of salinized cotton fields in Southern Xinjiang.