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In order to compare the influence of different soil types and stratification on water infiltration capacity, two main types of soil in the desert steppe, sierozem (S) and aeolian sandy soil (A), were selected, and infiltration simulation tests were conducted on homogeneous soil and layered soil (layer thickness 5, 10, and 20 cm), respectively. The results show that during the whole experiment, there was a small difference between S5A95 (aeolian sandy soil 95 cm thick was covered with sierozem 5 cm thick) and S10A90 (aeolian sandy soil 90 cm thick was covered with sierozem 10 cm thick) in the wetting front process, infiltration rate and cumulative infiltration, but there was a significant difference between S5A95 and S20A80 (aeolian sandy soil 80 cm thick was covered with sierozem 20 cm thick). In the initial infiltration stage, there was no significant difference between A5S95 (sierozem 95 cm thick was covered with aeolian sandy soil 5 cm thick) and A10S90 (sierozem 90 cm thick was covered with aeolian sandy soil 10 cm thick). However, with the increase of infiltration time, the wetting front process, A5S95, A10S90 and A20S80 had significant differences in terms of wetting front process, infiltration rate and cumulative infiltration. The infiltration capacity of A was significantly higher than that of S. Combined with linear Ä2 value and model parameters, the three infiltration models were comprehensively compared, and the fitting process and results of the general empirical model for the infiltration process of homogeneous soil and layered soil showed good results. Three models were used to simulate the water infiltration process of layered soil with different textures, and the order of the effect is as follows; general empirical model > Kostiakov model > Philip model. Soil type and layer thickness had a great influence on water infiltration process. When sierozem was covered with aeolian sandy soil 20 cm thick, the infiltration capacity was the best. As aeolian sandy soil was covered with sierozem 10 cm thick, the infiltration effect was the worst. Therefore, once coarse graying occurs on the surface of sierozem (the thickness of sand is more than 20 cm) or when the content of fine particles overlying aeolian sandy soil (the thickness of silt and clay soil is more than 10 cm) during ecological restoration is high, the soil hydrological characteristics will change significantly, which may lead to changes in vegetation types and even ecosystem structure. [ABSTRACT FROM AUTHOR]

A generalized water retention curve (WRC) model in a wide suction range considering the initial void ratio is presented in this paper. Both capillary and adsorbed water in soil pores are considered. Based on the experimental results that the adsorbed water content w a is not dependent on the initial void ratio, a new degree of saturation equation of adsorbed water is established. Meanwhile, a new degree of saturation equation of capillary water at various initial void ratios is proposed with a void ratio-related expression of the air entry value. Compared to Lu's model, only one parameter b is introduced in the established model, which can be easily calibrated using WRCs under two initial void ratios. The measured WRC results of 5 soils are used to verify the proposed model in comparison with the other 3 widely used WRC models. The soil used in the model validation covers a wide range of soil types from sandy soil to clay soil, including clayey silty sand, sandy clay till, clayey silt, expansive soil and lateritic soil. The proposed model is well verified for its ability to describe soil water retention characteristics in a wide suction range at various initial void ratios. [ABSTRACT FROM AUTHOR]