Search

Exploring soil water dynamics under different land use types is important for water resource management and vegetation restoration in the Loess Plateau. In this study, we investigated the hydrogen and oxygen isotopic compositions of soil water from four different land use types to explore the mechanism of soil water movement and transformation and analyse the influence of land use. The results show that the range of stable isotopes (δD and δ18O) in soil water was smaller than that in precipitation. Values for δD and δ18O in soil water showed relatively similar temporal variation, heavy isotopes were enriched in the soil water in July and depleted in October. Stable isotope values in shallow (<100 cm depth) soil water and deep (>200 cm depth) soil water were low. The δD and δ18O values in woodlands decreased gradually with increasing depth. Across the four land use types, the maximum variation in δD and δ18O was in the shallow depth of the soil profile. Groundwater was recharged mainly from precipitation and then from soil water. The ratio of groundwater recharge by soil water under different land use types followed this rank order: woodland (35.70%) > grassland (31.14%) > shrubland (29.47%) > cropland (29.18%). Matrix flow and preferential flow coexisted during infiltration, and the occurrence of preferential flow was related to the land use type. The main reason for the variation in isotopic composition in soil water is the difference in soil evaporation, which is influenced by different vegetation cover. Owing to the difference in soil evaporation and fractionation, precipitation on cropland, shrubland, and grassland can recharge more soil water than on woodland. [ABSTRACT FROM AUTHOR]

Landscape fragmentation affected the structure and function of the ecosystem, resulting in an impact on ecosystem service value (ESV). This paper analyzed the correlation between landscape fragmentation and ESV using land-use data from northern Shaanxi covering three periods from 2000 to 2020. The paper employed the granularity deduction method, spatial autocorrelation analysis, and value equivalent method to study the fragmentation characteristics of the regional landscape and the spatial-temporal evolution of ESV. The research findings indicated that the optimal granularity was 150 m, and the amplitude was 5 km × 5 km. The study found that the degree of landscape fragmentation was positively correlated with patch density (PD), division index (DIVISION), and Shannon's diversity index (SHDI), while negatively correlated with the largest patch index (LPI), patch cohesion index (COHESION), and effective mesh size (MESH). Moreover, the total ESV in the study area showed a decreasing trend, with grass, forest, and cultivated land being the three land-use types that contributed the most value. The analysis indicated that there was a negative correlation between the degree of landscape fragmentation and ESV. As the degree of landscape fragmentation increased, ESV decreased. The correlation between landscape fragmentation and ESV discussed in this paper provided valuable insights into the optimal utilization and sustainable development of regional land resources., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)