Optimization of soil hydrological properties in degraded grasslands by soil amendments

• Published in: Journal of hydrology (Amsterdam) 2024-11, Vol.643, p.131946, Article 131946
• Main Authors: Xu, Miaoping, Liu, Yinyi, Xi, Jiazhen, Li, Shiqing, Li, Ziyan
• Format: Article
• Language: English
• Subjects: Degraded grassland; Plant characteristics; Saturated hydraulic conductivity; Soil amendments; Soil properties; Soil water storage capacity
• ISSN: 0022-1694
• DOI: 10.1016/j.jhydrol.2024.131946

•Soil amendments significantly improved soil Ks in upper grassland soil.•Soil amendments increased SOM, FRB, and improved soil structure in upper soil.•Aluminum sulfate and biochar combination remarkably improved soil fertility and Ks.•Key drivers for affecting soil hydrology include SOM, FRB, SBD, and soil porosity. Soil amendments facilitate the restoration of degraded soil fertility and vegetation productivity. Soil hydrological functions are crucial for assessing soil degradation and restoration in grassland ecosystems. However, the manner in which soil amendments drive changes in the hydrological properties of grassland ecosystems at different soil depths remains unclear. In this study, we conducted a five-year soil amendment experiment in a semi-arid grassland of the Loess Plateau to evaluate the impact of aluminum sulfate (AS) and biochar (BC), both individually and in combination, on the hydrological properties of soil profiles. The results showed that AS significantly increased saturated water-holding capacity (SWHC) by 19.04 %, field capacity (FC) by 27.39 %, soil water storage (SWS) by 1.57 %, and saturated hydraulic conductivity (Ks) by 19.03 % in the upper soil layer (0–40 cm). BC application increased SWHC by 20.09 %, FC by 17.56 %, SWS by 12.94 %, and Ks by 16.66 % in the 0–40 cm soil layers. The combined effects of AS and BC optimized the soil hydrological properties by increasing SWHC, FC, SWS, and Ks by 25.74 %, 35.45 %, 18.47 %, and 25.80 %, respectively. These improvements were driven by significant changes in the soil organic matter, fine root biomass, total porosity, clay content, and soil bulk density. Notably, the soil amendments did not significantly affect the hydrological properties of the deep soil layer (40–80 cm). Our study demonstrated that the strategic use of AS and BC, particularly in combination, effectively enhanced soil fertility and hydrological functions, thereby increasing grassland ecosystem productivity. These findings offer critical insights for sustainable grassland management and highlight the potential of tailored soil amendments to restore and improve soil fertility and plant productivity in degraded grassland ecosystems.