In order to describe the quantitative relationship between soil salinity in the profile of a saline alkali?soil and leaching water volume

the effects of leaching water volume on soil water and salt movement in a typical saline alkali?soil in Ningxia Province treated with desulfurized gypsum were studied by an indoor soil column leaching test. The results showed that applying desulfurized gypsum had a positive effect on increasing water infiltration

reducing soil pH and salinity of the 0-20 cm soil layer

and soil desalinization rate was between 84.39% and 95.41%

but large leaching water volume might aggravate soil alkalization. Under?continuous leaching condition

the maximum desalting depth lied in the 60-80 cm soil layer. In the 0-20 cm soil layer

the?desalting?ratio of Cl- and Na+ had a small variation with the increasing amount of leaching water volume. Under small leaching?water volume

the?desalting?ratio of SO42- was lower than those of Cl- and Na+. Under large leaching?water volume

the?desalting?ratios of three ions were very close. In the 20-40 cm soil layer

the?desalting?ratio of major salt ion was in a descending order of Cl- > SO42- > Na+

and it increased quickly

finally remained stable. Under small leaching?water volume

Cl-

Na+

SO42- accumulated in the 40-60 cm soil layer. Under large leaching water volume

they continued downward migration. When leaching?watervolume reached 60 cm

SO42- and Na+ accumulated in the 80-100 cm soil layer

while Cl- migrated to >100 cm soil layer.