Temporal and Spatial Changes and Driving Forces of Soil Properties in Subtropical Mountainous Areas from 2017 to 2020: A Case Study of Baokang County, Hubei Province, China

Abstract

Understanding the mechanism of regional soil chemical property changes is crucial for guiding precise farming and further alleviating poverty in mountainous areas. Our aims were to monitor the temporal and spatial changes in the soil chemical property in subtropical mountainous areas and explore the effect of human activities, soil and topographic factors on the changes. In this study, a total of 332 soil samples were collected from 2017 to 2020 in Baokang County, subtropical mountainous area in central China. We analyzed the soil pH, soil organic matter (OM), soil available phosphorus (AP), soil available potassium (AK), soil total nitrogen (TN) and used Kriging interpolation to draw the map of spatial distribution of soil chemical properties in Baokang County from 2017 to 2020. The geographical detector was used to explore the driving forces of soil chemical property change over the years of research. The results show that: 1) from 2017 to 2020, soil pH, soil OM, and soil AP in Baokang County was increasing from north to south and the value of three chemical properties showed a slight decreasing trend. Soil AK showed an increasing trend, with higher values in Longping and Xiema towns and relatively lower values in Guoduwan, and soil TN was at a high level with large spatial variation. 2) The human activities, soil and topographic factors all affect soil properties in Baokang. In human activities, the cropping system and crop yield were strong explanatory factors for the changes in soil chemical properties, especially for AK and AP. The q values of all the indicators in the soil factor were relatively high, which displays that all indicators we selected affected the changes in soil properties. Soil OM and soil TN were the factors that affected each other with the greatest driving force, as were soil AP and soil AK. The driving force of DEM was greater among the topographic factors (slope, topographic relief and DEM), and its effect on five soil chemical properties showed that AK>AP>OM>TN>pH. 3) The interactions between each two factors showed a two-factor-enhanced relation, indicating that multiple factors form the soil properties of Baokang County. The findings of this study offer some scientific basis and suggestions for local government to control soil quality and economic development.