Effects of Soil Ameliorant on Characteristics of Soil Water and Salt Movement in Soda-salinized Meadow Soil

Understanding the relationship between the application of a soil ameliorant and soda-salinized meadow soil was crucial to investigate the characteristics of soil water and salt movement on different depths of soil layers. In this experiment, we conducted a simulated leaching soil column experiment in laboratory, set up five ameliorants application rates treatments, 0.0, 8.9, 44.3, 88.5, 221.25 kg·ha^-1, defined as CK, T1, T2, T3 and T4, respectively. And we analyzed the cumulative amount of water infiltration, wetting front depth and full salt content at different soil layers, in order to clarify the characteristics of soil water and salt movement with the number of different amendments. The results showed that compared with CK, when the infiltration time was 15 000 min, the cumulative infiltration of T1, T2, T3 and T4 increased by 158%, 167%, 205% and 257%, the migration depth of wetting front of T1, T2, T3 and T4 increased by 144%,145%,266% and 369%, respectively. And when the infiltration time was 25 000 min, the cumulative infiltration of T1, T2, T3 and T4 increased by 140%, 163%, 200% and 239%, the migration depth of wetting front with T4 reached 50 cm（the depth of soil loading is 50 cm）. However, that of T1, T2 and T3 increased by 155%, 176% and 284%, respectively. When the infiltration time was 37 440 min（water infiltration tended to stop, and the test was terminated）, compared with CK in 20-50 cm, the application of T3 and T4 treatment substantially increased the water content by 415% and 471%, increased the desalination rate by 512% and 556%, and the three-phase ratio was the closest to the ideal ratio. Based on comprehensive analysis of the effect of soil ameliorant on the characteristics of water and salt movement, according to the degree of soil salinity in this experiment, the optimum application rate for the specific soil salinization was proposed as T3 treatment of 88.5 kg·ha^-1 .