| Due to arid climate and water shortage,Xinjiang’s agricultural production mainly depends on irrigation.Accurately estimating the water requirement of cotton under drip irrigation under film is an important way to reasonably utilize limited water resources and ensure sustainable agricultural development in Xinjiang and other arid regions.Cotton field habitat control has become the main measure to effectively improve agricultural water resources utilization efficiency in arid areas.In order to study the water requirement of cotton under drip irrigation under different habitats,this study took cotton under drip irrigation activated water and conventional water irrigation in southern Xinjiang as research objects.The evapotranspiration and crop coefficients of cotton under film drip irrigation in different habitats were systematically studied.The main results are as follows:(1)Compared with the ETo results in the Korla region calculated by the FAO56 Penman-Monteith formula,the FAO24 Penman and 1948 Penman formulas overestimated ET0,the Hargreaves formula underestimated ETo,and the calculation results of the Priestley-Taylor formula and the FAO56 Penman-Monteith formula The results are more consistent.In addition,the path analysis method was used to determine the effect of different meteorological factors on the calculation result of ETo.Net solar radiation was the factor that had the greatest impact on ET0,followed by the temperature and saturation difference,respectively,while the impact of rainfall on ET0 was the least.(2)Peripheral water surface evaporation and weekly evapotranspiration,cumulative water surface evaporation and cumulative actual evapotranspiration have a linear relationship.The weekly accumulated temperature and the weekly evapotranspiration have a linear relationship.Under the drip irrigation under the film,the temperature difference between the 5-25 cm soil layer under the film and between the films gradually decreases with the increase of the soil thickness.There is a positive correlation between the average ambient ground temperature of each layer and the evaporation of the surrounding soil surface.Relative humidity is negatively correlated with water surface evaporation and positively correlated with average air temperature and average wind speed.The relative accumulated temperature is in a linear relationship with the relative water surface evaporation.(3)Activated water irrigation promotes the growth of cotton’s stem thickness,plant height,and leaf area.With the increase of irrigation volume,the ground temperature gradually decreased.The evaporation of the soil surface of the magnetized water irrigation treatment is less than that of the control treatment,while the evaporation of the soil surface of the deionized water treatment is greater than that of the control treatment.Both magnetized water and deionized water irrigation can increase soil moisture.Based on the cumulative leaf area index,surface coverage,soil water content,and ground temperature ratio as independent variables,and cumulative soil surface evaporation as the dependent variable,a cumulative power surface evaporation model was established in the form of a multivariate power function.(4)A modified double crop coefficient model based on leaf area index is used to calculate the crop coefficient of cotton under drip irrigation in Korla region.With the increase of irrigation volume,the basic crop coefficient and soil surface evaporation coefficient gradually increased.In addition,the crop coefficient of straw mulch treatment in the early stage of cotton growth is lower than that of magnetized water and de-e-water treatment,and the crop coefficient of straw mulch treatment in the middle and later stages is the highest.The crop coefficient of de-e-water treatment is greater than that of magnetized water treatment throughout the growing period.In the seedling stage of the magnetized water treatment and the full growth period of the de-e-water treatment,it is more helpful to control the inefficient consumption of water.(5)The application of PAM controls the daily evaporation and cumulative evaporation,and reduces the evaporation modulus coefficient;with the increase of PAM application,the effect of inhibiting soil surface evaporation is more obvious.The coefficients of cotton crops under film drip irrigation with 0(CK),0.5 kg/mu,1 kg/mu,2 kg/mu,and 3 kg/mu PAM showed an increasing trend and then decreasing.1.20,1.30,1.36,1.32,1.31.In addition,the crop coefficients of inter-membrane straw,sand-covering,PAM application,compaction and other inter-membrane cotton treatments showed a trend of increasing first and then decreasing. |
