The application of soil saline-alkali modifier is very important for soil improvement and crop growth

the organic acid-rich modifier is widely used because of its non-toxic and harmless effect. This paper selected the "hekang" saline-alkali scavenger as a typical organic acid modifier (hereinafter referred to as OA) through the indoor one-dimensional soil column infiltration test

and set up four groups of application content gradients (0.140

0.145

0.150 and 0.155 g/cm2)

with the treatment without OA as the control. At the same time

different OA application depth(0-10

15-20

25-30 cm) was also set to study the influence of OA on water and salt migration in saline-alkali soil. The results showed that mixed OA treatment with the increase of the applied amount

the soil infiltration capacity was decreased

as well as the steady infiltration rate. By fitting the infiltration process by Philip and Green-Amp infiltration models

the Philip model calculation parameters and fitting parameters calculated by the model parameter extrapolation relationship were in good agreement

and the relative errors were 9.82% and 2.23% respectively

which indicated that the Philip model is more suitable for the infiltration process with the application of organic acid modifier in soil. Both the absorption rate S and the steady permeability A decreased

and the saturated water conductivity KS and the soil water suction Sf decreased. Furthermore

the addition of OA could improve the water holding performance of soil and significantly improve the desalination rate of soil. After layer application OA treatment

with the increase of layer application depth

the cumulative infiltration increased

the steady permeability decreased

and the desalination rate of soil did not increase significantly. It is hoped that the organic acid modifier could provide theoretical basis for the application of saline-alkali soil.