Effects of Long-term Irrigation with Saline Water on Soil Physical-chemical Properties and Activities of Soil Enzyme

In order to analyze the feasibility of the saline water irrigation,an experiment was conducted under long-term location saline water irrigation in Hengshui.The effects of border irrigation and alter furrow and border irrigation with saline water on soil physical-chemical properties and activities of soil enzyme,and cotton yield after continuous seven years irrigation during the cotton growing season in 2012were studied.Results showed that border irrigation and alter furrow and border irrigation with saline water both led to salt accumulation in the soil profile,and the desalinization level was better in alter furrow and border irrigation treatment under furrow irrigation.With the increasing salinity of irrigation water,the soil salinity,soil bulk density,and pH value in 0-20cm soil layer increased.Compared with alter furrow and border irrigation treatment,the soil salinity and pH value of the corresponding border irrigation treatment were higher,while the soil bulk density was lower.Soil organic matter of border irrigation treatment at the initial and final stage of experiment was higher than that of corresponding alter furrow and border irrigation treatment by 8.9%~16.0%and 13.8%~19.4%,respectively.The recovery capability of soil invertase activity was strong in two irrigation treatments,but urease activity was relatively stable.Soil enzyme activity of border irrigation treatment washigher than that of alter furrow and border irrigation treatment when the soil salinity was the same.With the increasing soil salinity,the seed cotton yield of border irrigation treatment first increased and then decreased,while the yield of alter furrow and border irrigation treatment decreased linearly.The seed cotton yield of border irrigation treatments were higher than that of alter furrow and border irrigation treatments when the soil salinity was the same and lower than 0.8dS/m.The opposite was lower.By the analysis above,it was concluded that saline water irrigation led to soil salt accumulation,soil enzyme activity restraint,pH and topsoil bulk density rising.Compared with border irrigation treatment,alter furrow and border irrigation treatment had the superiority of lower soil salinity level and better desalinization effect,but it increased the topsoil bulk density,and decreased the organic matter,soil enzyme activity and seed cotton yield.