| Cotton is an important cash crop and is closely related to our life.South Xinjiang is the main cotton production area in China.However,there are many problems in south Xinjiang,such as water shortage,serious soil salinization,low agricultural irrigation efficiency and large residual mulch in farmland,which bring great challenges to cotton planting.In this paper,the non-membrane cultivated cotton "Zhongmian619" was taken as the research object,and six different irrigation graditions were set.The third irrigation treatment was used as the control group,and the total amount of conventional irrigation was 420 mm for mulched cotton in southern Xinjiang.Six different irrigation treatments were set as W1-W6 treatments.80%,90%,100%,110%,120% and 130% of the irrigation amount of the control group,respectively.Using SWAP model scale simulation of cotton in the "619" in the field of soil water under different irrigation gradient shift,the distribution and production situation,and on the field soil water distribution,water balance analysis,it is concluded that the highest water use efficiency(WUE)water treatment,for no membrane cotton future irrigation management and southern xinjiang cotton fields provide theoretical basis for water-saving irrigation.The main results are as follows:(1)Calibration and verification of SWAP model.The SWAP model was calibrated using the depth data of soil moisture content of 0～10cm,10～20cm,20～40cm and 40～60cm in the lowest irrigation treatment W1 and the highest irrigation treatment W6 in2019,and the measured yield data.The simulation accuracy of the model was verified by using the soil depth data of 0～10cm,10～20cm,20～40cm and 40～60cm of the lowest irrigation treatment W1 and the highest irrigation treatment W6 in 2020 and the measured yield data.The results show that: The calibrated model can be used to simulate soil water transport of cotton without film in southern Xinjiang.(2)Six different irrigation treatments in 2020 were simulated to analyze the law of soil water transport in cotton fields.Based on the field measured data in 2020,the calibrated SWAP model was used to simulate the crop transpiration,soil evaporation and soil water storage of "Zhongmian 619" during the growth period under six different irrigation treatments.The peak value of soil water storage corresponded to the date of each irrigation,which increased and then decreased during the growth period of cotton without film,and W6 had the largest soil water storage.The average daily maximum evapotranspiration of cotton plant and soil was in bud stage,and the evapotranspiration of W6 treatment was higher than that of the other five treatments.By analyzing the data of evapotranspiration,soil water storage,irrigation and precipitation,it can be concluded that the soil water in cotton field is in a state of dynamic balance.In 0-100 cm soil,the surface soil moisture content fluctuated the most,followed by the middle soil,and the deep soil moisture content was relatively stable.(3)Calculate and analyze the water use efficiency of cotton fields in 2020.The WUE of "Zhongmian 619" cotton field in 2020 was obtained by using yield data and simulated evapotranspiration data.Through calculation,W5 treatment was the highest WUE among six different irrigation treatments in 2020.Therefore,when the irrigation gradient is 120% of the conventional irrigation amount of mulched cotton in southern Xinjiang,the total irrigation amount is 10 times,and the total irrigation amount is 500 mm,the cotton field water use efficiency is the highest and the cotton yield is the highest. |
