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.

中文翻译：

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土壤改良剂优化退化草地土壤水文特性


土壤改良剂有助于恢复退化的土壤肥力和植被生产力。土壤水文功能对于评估草原生态系统的土壤退化和恢复至关重要。然而，土壤改良剂驱动不同土壤深度草地生态系统水文特性变化的方式仍不清楚。在这项研究中，我们在黄土高原的半干旱草原进行了一项为期五年的土壤改良试验，以评估硫酸铝 （AS） 和生物炭 （BC） 单独和组合对土壤剖面水文特性的影响。结果表明，AS 显着提高了上层土壤 （0-40 cm） 的饱和持水能力 （SWHC） 增加了 19.04 %，田间容量 （FC） 增加了 27.39 %，土壤储水量 （SWS） 增加了 1.57 %，饱和导水率 （Ks） 增加了 19.03 %。BC 施用使 0-40 cm 土层的 SWHC 增加了 20.09 %，FC 增加了 17.56 %，SWS 增加了 12.94 %，Ks 增加了 16.66 %。AS 和 BC 的联合效应通过分别增加 SWHC、FC、SWS 和 Ks 来优化土壤水文性质 25.74 %、35.45 %、18.47 % 和 25.80 %。这些改进是由土壤有机质、细根生物量、总孔隙度、粘土含量和土壤容重的显著变化推动的。值得注意的是，土壤改良剂对深层土壤层 （40-80 cm） 的水文特性没有显著影响。我们的研究表明，战略性地使用 AS 和 BC，特别是结合使用，有效地提高了土壤肥力和水文功能，从而提高了草原生态系统的生产力。 这些发现为可持续草原管理提供了重要见解，并强调了量身定制的土壤改良剂在恢复和提高退化草原生态系统中的土壤肥力和植物生产力的潜力。