Soil and water conservation measures, widely promoted to control soil erosion in erosive orchards, can alter soil aggregates, thereby influencing the soil quality index (SQI). However, it's still unclear how these measures affect soil aggregate nutrients, stoichiometry, and their association with SQI at a long-term timescale. This study focused on a 22-year homogeneous orchard in subtropical hilly region. Five soil and water conservation measures, namely clean tillage (CT), engineering measures (EM), tillage measures (TM), non-leguminous biological measures (NLBM), and leguminous biological measures (LBM), were implemented. Sampling depths were 0–20 cm, 20–40 cm, and 40–60 cm. The results revealed that LBM significantly enhanced SQI across the soil profile, increased the proportion of macroaggregates, and improved aggregate stability, soil organic carbon, and total nitrogen. Additionally, LBM demonstrated the highest capacity for carbon and nitrogen preservation. Soil stoichiometry revealed carbon and nitrogen limitations in the orchard soils, and leguminous cover proved effective in alleviating these limitations and maintaining the stoichiometric balance of soil aggregates. Under a long-term timescale, these measures mitigated or even surpassed the impact of soil depth on soil aggregates and SQI. The improvement of orchard SQI through the measures was primarily achieved by enhancing aggregate stability. There was no significant correlation between soil organic carbon and SQI in relation to fruit yield, ascribed to the intense competition for water and nutrients between cover plants and citrus trees. In conclusion, LBM emerges as the most beneficial soil and water conservation measure for enhancing orchard SQI, preserving nutrients, and maintaining aggregate stoichiometric balance. It holds the potential to improve orchard yield and contribute to sustainable development.

为控制侵蚀性果园的水土流失而广泛推广的水土保持措施可以改变土壤团聚体，从而影响土壤质量指数（SQI）。然而，目前尚不清楚这些措施如何影响土壤聚合养分、化学计量及其与 SQI 的长期关系。本研究以亚热带丘陵地区22年均质果园为研究对象。实施清洁耕作（CT）、工程措施（EM）、耕作措施（TM）、非豆科生物措施（NLBM）、豆科生物措施（LBM）五项水土保持措施。采样深度为0-20 cm、20-40 cm、40-60 cm。结果表明，LBM显着提高了整个土壤剖面的SQI，增加了大团聚体的比例，并提高了团聚体稳定性、土壤有机碳和全氮。此外，LBM 表现出最高的碳和氮保存能力。土壤化学计量揭示了果园土壤中碳和氮的限制，而豆科植物覆盖被证明可以有效缓解这些限制并维持土壤团聚体的化学计量平衡。从长期来看，这些措施减轻甚至超过了土壤深度对土壤团聚体和SQI的影响。这些措施对果园SQI的改善主要是通过增强总量稳定性来实现的。土壤有机碳和 SQI 与果实产量之间没有显着相关性，这归因于覆盖植物和柑橘树之间对水和养分的激烈竞争。总之，LBM 是提高果园 SQI、保存养分和维持总体化学计量平衡最有益的水土保持措施。它具有提高果园产量并促进可持续发展的潜力。