Impact of deeper groundwater depth on vegetation and soil in semi-arid region of eastern China

Abstract

IntroductionUnderstanding the impact of deep groundwater depth on vegetation communities and soil in sand dunes with different underground water tables is essential for ecological restoration and the conservation of groundwater. Furthermore, this understanding is critical for determining the threshold value of groundwater depth that ensures the survival of vegetation.MethodThis paper was conducted in a semi-arid region in eastern China, and the effects of deep groundwater depth (6.25 m, 10.61 m, and 15.26 m) on vegetation communities and soil properties (0–200 cm) across three dune types (mobile, semi-fixed, and fixed dunes) were evaluated in a sand ecosystem in the Horqin Sandy Land.ResultsFor vegetation community, variations in the same species are more significant at different groundwater depths. For soil properties, groundwater depth negatively influences soil moisture, total carbon, total nitrogen, available nitrogen, available phosphorus concentrations, and soil pH. Besides, groundwater depth also significantly affected organic carbon and available potassium concentrations. In addition, herb species were mainly distributed in areas with lower groundwater depth, yet arbor and shrub species were sparsely distributed in places with deeper groundwater depth.DiscussionAs arbor and shrub species are key drivers of ecosystem sustainability, the adaptation of these dominant species to increasing groundwater depth may alleviate the negative effects of increasing groundwater depth; however, restrictions on this adaptation were exceeded at deeper groundwater depth.

Indirect regulation of topsoil nutrient cycling by groundwater depth: impacts on sand-fixing vegetation and rhizosphere bacterial communities

“…This may explain why soil nutrient levels increased as GTD increased in SW. Conversely, as the groundwater table continued to decrease, reduced soil water content and heightened aeration in the vadose zone accelerated the decomposition of soil organic matter, leading to a decrease in SOC. This aligns with the trend reported by Zhao et al (2023) for the Horqin sand plain, where nutrients exhibited a decline with increasing GTD. In this study, SOC, TN, and AP exhibited an initial increase, followed by a decrease in the GTD (Figure 3C).…”

A Systematic Review on Digital Soil Mapping Approaches in Lowland Areas

“…Similarly, sediment deposition in particular spots, often associated with water bodies, can result in unique soil characteristics [108]. Hydrological processes, such as seasonal flooding or changes in groundwater levels, can also influence soil properties in specific locations [109][110][111]. These fine-scale variations, although they might appear minor in the broader context of lowland landscapes, are essential to consider when mapping and characterizing lowland soils accurately.…”