Effect Of Film-Mulched Drip Irrigation With Brackish Water On Soil Water And Salt Movement And Gotton Growth

In order to alleviate the shortage of fresh water resources in southern Xinjiang,reasonable use of brackish water for irrigation is a feasible method.A total of 6 different ratios of fresh water and brackish water were set in this study,namely ratios of fresh water and brackish water 1:0(control),4:1(treatment 1),3:2(treatment 2),2:3(treatment 3),1:4(treatment 4)and 0:1(treatment 5).Combined field experiments with indoor analysis,the study was intended to reveal the characteristics of water and salt transport in the soil of cotton field with drip irrigation of brackish water under film,and explore the response of cotton to salt under drip irrigation with brackish water.The results revealed that:(1)With the development of growth period,the soil salinity under different brackish water treatment increased gradually,while there was a tendency that the water content increased first and then decreased;with the increase of salinity of irrigation water,the water content of soil increased slightly,while the salt content increased significantly,among the treatments,the soil salinity under treatment 1 increased least compared with the control.At the end of the experiment,all treatments showed the salt accumulation more than the initial salinity within 1 m soil depth,of which the control salt accumulation was at least 22.97%,followed by treatment 2 at 45.06%and treatment 5 at 131.03%.(2)Compared with the control,the irrigation water of treatment 1 had little effect on cotton growth.The high salinity irrigation water would inhibit the growth of plant height and stem diameter,reduce the leaf area index,chlorophyll,and dry matter of cotton.With the increase of salinity,the cotton yield gradually decreased,among which treatment 1 decreased 11.85%compared with the control.With the increase of salinity,the short fiber index of cotton increased in different degrees,but the difference was not significant.Compared with the control,other qualities decreased to different degrees.Overall,the quality of cotton decreased with the increase of salinity.(3)With the increase of salinity,the Na+and Cl-content in cotton plants increased.The salt content of treatment 1 increased least compare with control,but the salt accumulation of a single plant fluctuated;the content and accumulation of Ca2+ decreased with the increase of salinity.The nutrient content of cotton increased first and then decreased with the increase of salinity,and treatment 1 was the highest.while the nutrient accumulation in single plant decreased,and treatment 1 had the smallest decrease compared with the control.Under the treatment 1,the ratios of fresh water and brackish water was 4:1,the accumulation of soil salt was the least,the accumulation of salt in cotton was low,and the absorption of nutrients was less affected,and the inhibition of cotton growth was small,even it can promote the cotton growth.Therefore,under the condition of this experiment,with combination of the effects of brackish water on soil water and salt movement,cotton growth,yield and quality,cotton salt content and accumulation,it was confirmed that the optimal ratios of fresh water and brackish water is 4:1.