Land degradation and the associated soil acidity are critical challenge for crop production in Ethiopian highlands. Since liming is expensive, farmers have developed an alternative agroforestry system by integrating Acacia decurrens into their landscapes. The expansion rate of this system was assessed over the last three decades. The effects of the agroforestry system and charcoal-making kiln sites on soil properties were investigated for over five years compared to the adjacent croplands. Soil samples were collected from A. decurrens plantations, kiln sites, and adjacent croplands at 0–15 and 15–30 cm soil depths. In the last 30 years, the plantation and croplands increased by 8% and 17.5%, respectively, compared to the land-use system in 1993, mainly at the expense of grassland and abandoned land. The main incentive for expansion of A. decurrens plantations was farmers’ income generated from charcoal making. This intervention also improved soil properties with a significantly positive effect on soil pH, soil organic carbon (SOC), cation exchange capacity (CEC), and available Bray phosphorus (Bray-P) compared to the adjacent croplands. Results revealed that the SOC content in year 2 increased significantly (1.3–1.7 times) under A. decurrens plantation compared to adjacent crop fields. Moreover, soil pH increased by one unit on charcoal-making fields, which was equivalent to application of 4–5 t lime ha⁻¹, while SOC increased by ~ 10% on kiln sites compared to the control. Charcoal making kiln spots increased available soil phosphorus by 112% compared to the adjacent non-kiln sites. The Bray- P was strongly and significantly (P < 0.05) correlated (r = 0.75) with soil pH. We conclude that integrating A. decurrens-based agroforestry practices would improve livelihoods by restoring degraded lands, improving income generation and carbon sequestration.

土地退化和相关的土壤酸度是埃塞俄比亚高地作物生产的关键挑战。由于石灰价格昂贵，农民通过将Acacia decurrens整合 到他们的景观中来开发一种替代农林业系统 。该系统的扩展率是在过去三年中评估的。与邻近的农田相比，农林业系统和木炭窑址对土壤性质的影响进行了五年多的调查。从A. decurrens收集土壤样品  0-15 厘米和 15-30 厘米土壤深度的种植园、窑址和邻近农田。近 30 年来，人工林和耕地比 1993 年的土地利用制度分别增加了 8% 和 17.5%，主要是以草地和废弃地为代价的。扩大A. decurrens 种植园的主要动力是农民从木炭制造中获得的收入。与邻近农田相比，这种干预措施还改善了土壤性质，对土壤 pH 值、土壤有机碳 (SOC)、阳离子交换容量 (CEC) 和有效布雷磷 (Bray-P) 产生了显着的积极影响。结果显示，在A. decurrens下，第 2 年的 SOC 含量显着增加（1.3-1.7 倍）种植园与邻近的农田相比。此外，与对照相比，制炭场的土壤 pH 值增加了 1 个单位，相当于施用 4-5 吨石灰 ha ^-1，而窑场的 SOC 增加了约 10%。与邻近的非窑址相比，木炭窑址增加了 112% 的有效土壤磷。Bray-P 与土壤 pH 值有很强且显着的相关性（P < 0.05）（r = 0.75）。我们得出结论，整合基于A. decurrens的农林业实践将通过恢复退化的土地、增加收入和碳封存来改善生计。