Research for the Effect of Shallow-Tight Type Subsurface Drain Pipes on Improving Soda Saline-alkaline Land

To study the practice of subsurface drain pipe for improving soda saline-alkaline land,A soda saline-alkaline land in Daqing was selected to carry out field experiment and investigate the leaching desalination of different drain pipe spacing(5,10,15 m) and burial depth(0.8,1.0,1.2 m).The result show that with use of three irrigation leaching and buried drain pipes,the plough layer soil salinity is significantly reduced;furthermore,the smaller the spacing and depth of covered pipe are,the higher the efficiency of the average drainage is;and the greater drainage salinity and the higher the efficiency of the soil desalination are,the better the soil improvement is.Under condition of 5 m spacing and 0.8 m depth after processing with leaching drainage,the average efficiency is 2.08%,increases by 13.66%;the soil salinity is 0.16%,decreases by 23.81%.The best laid spacing parameter of the soda saline-alkaline land down stains desalination is 5 m and the depth of 0.8 m,which can not only effectively exclude soil salinity,but also to ensure the uniformity of the plow layer soil desalination.