Research On Soil Water-salt Distribution And Cotton Growth Characteristics Using De-electronic Brackish Water Drip Irrigation With Plastic Mulh

Brackish water is abundant in the xin jiang region,the saline soil are widely distributed,due to the lack of fresh water resources,long-term use of brackish water irrigation soil lead to secondary salinization,restricting the development of agricultural economy,to use de-electronic brackish water can reduce the negative effects of brackish water irrigation on crop.In this study,adopts to combine one dimensional vertical water infiltration test with the field test.In this paper,the effects of de-electronic brackish water and combining de-electronic brackish water with soil containing polyacrylamide on infiltration characteristics were studied under the condition of one-dimensional vertical infiltration.The effects of the amount of water and polyacrylamide on the distribution of soil water salt and the growth characteristics of cotton were studied.The main results were as follows:(1)With the extension of infiltration time,under the same infiltration time condition,the infiltration rate,cumulative infiltration capacity and wetting front migration depth of the de-electronic brackish water were greater than that of brackish water.With the application rate of polyacrylamide,the cumulative infiltration capacity,wetting front migration depth and infiltration rate decreased with the application rate of polyacrylamide,and then increased.The infiltration process of electronic brackish water and brackish water.was well described by Kostiakov model and Philip model.At the same depth,the soil moisture content in the de-electronic brackish water was greater than that of Ibrackish water,and the soil salinity was less than that of brackish water.Under the condition of different application rate of polyacrylamide,the soil moisture content increased with the increase of application rate of polyacrylamide,and then decreased.When the application rate of polyacrylamide was 0.04%,the soil moisture content was the highest and the desalting effect was the best.(2)According to comparing the soil water and salt distribution,water consumption,salt deposition,cotton growth characteristics(plant height,leaf area,production),water use efficiency,the difference among irrigaton water treatments were analysed.Average soil water content increased with the increased amount of irrigation water in whole growth period,soil water during flowering fruiting period of the soil profile of 0-60cm was the maximum during whole growth period,W375 irrigation levels were increased by 10.7%,16.5%,32.5%and 54.0%,respectively,compared with W325,W275,W225 and W175.The water consumption increased with the increased amount of irrigation water during the whole growth period,and the water consumption during flowering fruiting period was the maximum.The content of soil salinity during the whole period was:W375<W175<W225<W325<W275.Plant height,stem diameter and leaf area index increased with the increased amount of irrigation water.When the irrigation water was 325m3/mu,the number of effective bolls per plant was the maximum.According to the water production function of the whole growth period,when the irrigation amount reaches 320m3/mu,the maximum yield is 459.36kg/mu.Compared with brackish water,at 325m3/mu irrigation level,the cotton yield and water use efficiency increased by 13.4%and 28.5%respectively.(3)According to comparing the soil water and salt distribution,water consumption,salt deposition,cotton growth characteristics(plant height,leaf area,production),water use efficiency,the difference among application amount of polyacrylamide treatments were analysed.When the amounts of PAM was 0kg/mu,0.5kg/mu,lkg/mu,the average moisture content of the soil profile of 0-60cm was greater than that of the untreated PAM.The amount of PAM was 0kg/mu,0.5kg/mu,1.0kg/mu,1.5kg/mu,and 2.0kg/mu,the water consumption in the flower period accounted for 33.4%,36.4%,34.6%,35.1%and 39.4%,respectively.The maximum water consumption of PAM was 1kg/mu.The soil salinity of PAM treatments was measured as:1.0kg/mu<2.0kg/mu<0.5kg/mu<0.5kg/mu<0kg/mu.When the application amount of PAM was 1kg/mu,reduced the amount of salt effectively,the cotton plant height and biomass were the maximun,increased the cotton yield by 19.5%.(4)The Logistic model can reasonably describe the trend of cotton plant height,leaf area index and biomass change with the growth period.Through the parameters of irrigation and application amount of polyacrylamide treatments and normalization processing bulit the growth model for plant height,leaf area index and biomass.The model could describe the trend well.