Soil degradation remains a challenge in African highlands, where land management lacks a strong context-specific evidence base. We investigated the impacts of recently implemented soil and water conservation (SWC) practices—farmyard manure addition, incorporation of crop residues in soil and fanya juu terracing under an agroforestry system on soil health indicators in the East Usambara Mountains of Tanzania. Farmers' observations of soil changes were combined with conventional soil testing to assess the initial impacts of SWC practices relative to conventional non-SWC practice. Majority of farmers (66%–83%) reported that combining fanya juu terracing with organic amendments led to soil colour change from red to black and an increase in crop yield. Despite the observed darkening of the soil, there was no significant increase in soil organic carbon stock and the contents of N, P, K. There were important changes in soil physical properties, including greater aggregate stability (mean weight diameter of 1.51–1.71 mm) in the SWC plots, a greater volume of transmission pores (>60 μm) and coarse storage pores (10–60 μm) in the surface soil layer (0–15 cm), and greater volume of fine storage pores (0.2–10 μm) and residual pores (0.2 μm) in the sub-surface layer (15–30 cm) of the SWC plots compared with the conventional plots. These changes indicate that SWC rapidly enhances infiltration and retention of water within the root zone, which are important for increasing crop yields and improving the resilience of the agro-ecosystem to environmental stress. Combining SWC with effective soil fertility management is needed for sustainable highland agriculture.

中文翻译：

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通过农民观察和常规土壤测试评估气候智能型农业下的土壤系统变化

土壤退化在非洲高地仍然是一个挑战，那里的土地管理缺乏强有力的针对具体情况的证据基础。我们调查了最近实施的水土保持 (SWC) 实践——农田肥料添加、农作物残留物在土壤中的掺入和农林业系统下的fanya juu梯田对坦桑尼亚东乌桑巴拉山脉土壤健康指标的影响。农民对土壤变化的观察与常规土壤测试相结合，以评估 SWC 实践相对于传统非 SWC 实践的初始影响。大多数农民 (66%–83%) 报告说，结合番鸭酒使用有机改良剂的梯田导致土壤颜色从红色变为黑色，并增加了作物产量。尽管观察到土壤变黑，但土壤有机碳储量和 N、P、K 含量没有显着增加。土壤物理性质发生了重要变化，包括更大的团聚体稳定性（平均重量直径为 1.51-1.71 毫米) 在 SWC 图中，表层土层 (0-15 cm) 的传输孔 (>60 μm) 和粗蓄水孔 (10-60 μm) 的体积更大，细蓄水孔的体积更大 (0.2-10与常规图相比，SWC 图的次表层（15-30 cm）中的残余孔隙（0.2 μm）。这些变化表明 SWC 迅速增强了根区水分的渗透和滞留，这对于提高作物产量和提高农业生态系统对环境压力的抵御能力非常重要。可持续高原农业需要将 SWC 与有效的土壤肥力管理相结合。