Soil fertility is key to sustainable intensification of agriculture and food security in sub-Saharan Africa. However, when soil nutrients are not adequately managed, smallholder farming practices slowly erode soils to almost inert systems. This case study contributes to the understanding of such failures in marginal areas. We integrate agronomic and social sciences approaches to explore links between smallholder households’ farming knowledge and soil fertility in an ethnopedological perspective. We interview 280 smallholder households in two areas of the Ethiopian highlands, while collecting measures of 11 soil parameters at their main field. By analyzing soil compositions at tested households, we identify a novel measure of soil management ability, which provides an effective empirical characterization of the soil managing capacity of a household. Regression analysis is used to evaluate the effects of household knowledge on the soil management ability derived from laboratory analysis. Results highlight the complexity of knowledge transmission in low-input remote areas. We are able to disentangle a home learning and a social learning dimension of the household knowledge and appraise how they can result in virtuous and vicious cycles of soil management ability. We show that higher soil management ability is associated with farmers relying to a great extent on farming knowledge acquired within the household, as a result of practices slowly elaborated over the years. Conversely, lower soil management ability is linked to households valuing substantially farming knowledge acquired through neighbors and social gatherings. The present study is the first to formulate the concept of soil management ability and to investigate the effects of the presence and the types of farming knowledge on the soil management ability of smallholder farmers in remote areas. We show that farming knowledge has a primary role on soil fertility and we advise its consideration in agricultural development policies.

土壤肥力是撒哈拉以南非洲可持续集约化农业和粮食安全的关键。但是，当土壤养分管理不当时，小农耕作方法会慢慢将土壤侵蚀成几乎惰性的系统。该案例研究有助于了解边缘地区的此类故障。我们将农艺学和社会科学方法相结合，以人种学的视角探索小农户的农业知识与土壤肥力之间的联系。我们采访了埃塞俄比亚高地两个地区的280个小农户，同时在其主要田地收集了11种土壤参数的测量值。通过分析受测家庭的土壤成分，我们确定了土壤管理能力的新指标，这为家庭土壤管理能力提供了有效的经验表征。回归分析用于评估家庭知识对实验室分析得出的土壤管理能力的影响。结果突出了低投入偏远地区知识传播的复杂性。我们能够解开家庭学习和社会学习家庭知识的维度，并评估它们如何导致土壤管理能力的良性循环和恶性循环。我们表明，由于多年以来缓慢制定的实践，较高的土壤管理能力与农民在很大程度上依赖于家庭内部获得的农业知识有关。相反，较低的土壤管理能力与家庭非常重视通过邻居和社交聚会获得的农业知识有关。本研究是首次提出土壤管理能力的概念，并研究耕种知识的存在和种类对偏远地区小农户土壤管理能力的影响。