Effect of environmental factors on soil properties under different land use types in a typical basin of the North China Plain

Soil physicochemical properties can not only reflect ecosystem integrity, land quality and biogeochemical processes, but also are impacted by diverse land use types formed by intensive human activities. Exploring the comprehensive function of land use types and environmental factors on soil properties are of great significance for the relative land management, nutrition cycling and agricultural sustainable development. And little previous studies considered the inherent relations between soil properties under the dual effects of the above two, especially in an area with high land use intensity. This study tried to achieve the comprehensive research of human activities and environmental factors on soil properties through the study of the functions on soil properties from the environment factors under different land use types in the Beijing-Tianjin-Hebei region, which is a typical area with the most intense human activities in China. In this study, soil samples were collected in an area typified by intensive human activities in the Baiyangdian Watershed in the Beijing-Tianjin-Hebei region. The relationships between soil properties and environmental factors as well as the relationships between soil properties and land use intensity were explored by principal component analysis and geographically weighted regression (GWR) respectively. Additionally, impacts on soil properties from environmental factors were explored by structural equation modeling (SEM). GWR results suggested that pH was positively related to land use intensity (LUI); comparatively, all other soil properties were negatively related to LUI. SEM results showed that precipitation, temperature, and elevation all had direct and indirect influences on soil properties. Moreover, soil organic carbon was not only directly affected by environmental factors, but also indirectly through total phosphorus content in residential areas and plain farmland, pH in mountainous farmland areas, and bulk density in residential areas and mountainous farmland. Our work focus on the combined function of environmental factors and land uses on soil properties under various land use types with different human activities intensities. Our main conclusion from the above findings was that precipitation and temperature are both important factors that impact soil properties. High temperature and improper agricultural activities also reduced soil carbon accumulation. These findings underscore that scientific fertilizer addition during farming and soil quality management such as planning a proper reclamation range should be advocated in areas with intensive human activities. Taken together, our research will allow for a better understanding of the variations in soil properties and other influential factors in the context of human activities.