Shuitu baochi tongbao (Oct 2023)
Dynamic Simulation of Soil Moisture Under Typical Land Preparation in Semi-arid Loess Area Using HYDRUS-1D Model
Abstract
[Objective] The dynamic characteristics of soil moisture under different land preparation measures were analyzed in order to provide a scientific basis for assessing the eco-hydrological benefits of slope land preparations and for promoting vegetation restoration in arid areas. [Methods] We used an in-situ controlled study of natural slopes, fish-scale pits, and reverse slopes of a Pinus tabulaeformis forest in a semi-arid loess area along with dynamic monitoring of soil moisture and rainfall events and HYDRUS-1D software simulations to quantify the effects of different land preparation measures on the vertical migration characteristics of soil moisture. [Results] ① The simulation accuracy of the one-dimensional unsaturated soil moisture transport numerical model for soil moisture in the 0—40 cm layer was greater than that of the 40—100 cm layer, which was suitable for the simulation of surface (0—40 cm) soil moisture. During the entire study period, under the same rainfall conditions, the soil moisture fluxes of the fish-scale pits and the reverse slope terraces were significantly higher than the soil moisture flux of the corresponding natural slope (p20 mm, the values for both fish-scale pits and reverse slope terraces at 40 cm were 2.61% and 1.92%. There were significant differences in soil moisture flux between each layer of the fish-scale pits and the reverse slope terraces. When the rainfall was 5—10 mm, there were significant differences in soil moisture fluxes between each layer of the fish-scale pits (p<0.05), and there were significant differences in soil moisture fluxes between 20—40 cm in the reverse slope terraces (p<0.05). [Conclusion] The fish-scale pits and the reverse slope terraces had different effects on soil moisture. The fish-scale pits had better water retention under rainfall conditions.
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