Farmers’ diagnosis of current soil erosion status and control within two contrasting agro-ecological zones of Rwanda

Abstract

Rwanda, the land of thousand hills, hosts a large diversity in environmental conditions, regionally classified into agro-ecological zones (AEZs). This paper aimed to explore the current perceptions of farmers on soil erosion processes, soil erosion control (SEC) and their impacts on the adopted farming systems within two watersheds from contrasting AEZs, i.e. Murehe in the Eastern plateau and Tangata in the Buberuka highlands, using participatory survey data from 300 households collected during face-to-face interviews in 2017. Both zones differed in socio-economic environment, the short distance to the capital favouring higher education levels in Murehe, while the production of cash crops in the well aroused and more fertile, yet also more steeply sloping Tangata watershed offered higher incomes. Despite these differences, adoption of SEC measures proved uniform across both zones reflecting strong but seemingly low-differentiated governmental supported action. Diversity in available erosion control measures within both zones was large, but dominated by combined structural and vegetative measures. Most farmers relied on government support for the installation of bench terraces, but adopted also other SEC such as progressive terracing and agroforestry. SEC adoption furthermore changed the agricultural systems heading to crop rotation, contour tillage and combined application of (in)organic fertilizers, albeit mainly fostered through subsidies. Despite these efforts, SEC seemed to be only partly effective in the highlands where erosion continued to have multiple high impact consequences affecting the entire landscape. High rainfall amounts and steep slopes were held responsible. The potential contribution of land management to erosion was generally less recognized, except for the tillage practices. Erosion was considered most prominent in the mid-season periods on Acrisols located at vulnerable landscape positions. These research results might question the effectiveness of the adopted control practices in particular AEZs. However, it can also pinpoint to the need of a much more integrated watershed management approach. The long-standing exposure of the surveyed population to diverse erosion control measures offers a unique insight that can be useful for other tropical highland countries.