Experimental study on salt movement in soil under saline and fresh water alternate leaching

Laboratory tests were performed on alternate leaching of soil columns with fresh water and saline water at degree of mineralization of 2 g/L and 4 g/L respectively for preliminary research of the movement laws of salt in soil after saline and fresh water alternate irrigation.The result shows that the salt in soil gradually moves from the surface down toward the bottom under alternate leaching of saline and fresh water,and the salt accumulates in soil columns under the two test conditions,with more salt accumulated if saline water at degree of mineralization of 4 g/L is adopted,and that the distributions of Na+ and Ca2+ as well as the variation of EC value in soil solution are almost the same under two test conditions.Under such test conditions,the increase of salt content in soil does not cause soil alkalinization,and the EC values of soil solution under the two irrigation conditions are both less than 4 dS/m after irrigation,which are within the range of salt tolerance of crops.Thus,the saline and fresh water alternate irrigation could be applied to fields for crop planting.