Abstract

Soil moisture is a crucial factor limiting the growth and survival of plants on the Loess Plateau. Its level has a severe impact on plants’ growth and development and the type and distribution characteristics of communities. This study area is the Jihe Basin in the Loess Plateau, China. Multiple linear regression models with different environmental variables (land use, topographic and meteorological factors, etc.) were developed to simulate soil moisture’s spatial and temporal changes by integrating field experiments, indoor analysis, and GIS spatial analysis. The model performances were evaluated in the Jihe Basin, with soil moisture content measurements. The result shows that soil moisture content is positively correlated with soil bulk density, monthly rainfall, topographic wetness index, land use coefficient, and slope aspect coefficient but negatively correlated with the monthly-averaged temperature and the relative elevation coefficient. The selected variables are all related to the soil moisture content and can account for 75% of the variations of soil moisture content, and the remaining 25% of the variations are related to other factors. Comparing the simulated and measured values at all sampling points shows that the average error of all the simulated values is 0.09, indicating that the simulation has high accuracy. The spatial distribution of soil moisture content is significantly affected by land use and topographic factors, and seasonal variation is remarkable in the year. Seasonal variation of soil moisture content is determined by the seasonal variation of rainfall and the air temperature (determining evaporation) and vegetation growth cycle. Therefore, the proposed model can simulate the spatial and temporal variation of soil moisture content and support developing the soil and water loss model on a basin scale.

Highlights

  • The Loess Plateau of China, situated in the upper and middle reaches of the Yellow River, covers about 630,000 km2, has an elevation of 1200–1600 m above sea level and is predominantly covered by loess deposits

  • (1) The model equation obtained through multivariate linear regression analysis is

  • The results showed that the simulation accuracy of soil moisture content was high

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Summary

Introduction

The Loess Plateau of China, situated in the upper and middle reaches of the Yellow River, covers about 630,000 km, has an elevation of 1200–1600 m above sea level and is predominantly covered by loess deposits. Based on previous studies [16,17,18,19,20,21,22] and research results of small watersheds [23], the objective of this study was to estimate the soil moisture content in large-scale basins considering various factors affecting soil moisture content [24,25,26] It would lay a foundation for studying the regional soil and water loss model and provide a scientific basis for soil and water conservation and ecological restoration in the Loess Plateau, China

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