The growing need to intensify smallholder farming systems to enhance food security for a rapidly growing population in sub-Saharan Africa constitutes a major sustainability challenge. Intensification of agriculture has often resulted in degraded, highly vulnerable, exhausted and unproductive soils. Even though smallholder farming systems are heterogeneous and dynamic, conventional approaches to improving soil management have focused on promoting one or two technologies, informed by coarse-resolution assessments, rather than tailoring technologies to context. This has resulted in technologies that have been promoted not being locally adapted. The research reported here explores the extent to which farmers' indicators of soil quality vary with land degradation status and gender and can be used in selecting locally appropriate land restoration practices. Knowledge was elicited from 150 smallholder farmers across a land degradation gradient in Rwanda through combined use of a systematic knowledge-based systems approach (AKT5), and a participatory knowledge sharing method for indicators of soil quality (InPaC-S). Data were analysed using R software through frequency statistics, 'ggplot'-generated bar plots and Chi-square tests of independence. Farmers described 12 indicators of soil quality with a mean of five per farmer. The four most frequently mentioned were: soil colour (96%), indicator plants (90%), crop vigour (71%) and soil texture (67%). Farmers' knowledge about 10 out of 12 indicators varied with land degradation status (p b .05), and there were other variations according to location of fields along slopes, and gender. Farmers had knowledge of 51 indicator plants and 22 soil macrofaunal species and mentioned seven soil management practices, including: compost manure (83% of farmers), livestock manure (64%) and tree biomass incorporation (54%). There were variations in the practices by degradation status, slope location and gender. These variations revealed the importance of matching management options to ecological context and farmer circumstances to foster adoption. There were relationships between farmers' knowledge of indicators of soil quality and their soil management practices. This research has shown that acquiring farmers' knowledge about soils can help to identify fine-scale contextual differences useful for informing the design of soil management options and it is recommended that this is done in future so that appropriate options can be offered to different farmers making them more likely to be adopted.

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Densely populated rural areas in the East African Highlands have faced significant intensification challenges under extreme population pressure on their land and ecosystems. Sustainable agricultural intensification, in the context of increasing cropping intensities, is a prerequisite for deliberate land management strategies that deliver multiple ecosystem goods (food, energy, income sources, etc.) and services (especially improving soil conditions) on the same land, as well as system resilience, if adopted at scale. Tree based ecosystem approaches (TBEAs) are among such multi-functional land management strategies. Knowledge on the multi-functionality of TBEAs and on their scaling up, however, remains severely limited due to several methodological challenges. This study aims at offering an analytical perspective to view multi-functional TBEAs as an integral part of sustainable agricultural intensification. The study proposes a conceptual framework to guide the analysis of socio-economic data and applies it to cross-site analysis of TBEAs in extremely densely populated Rwanda. Heterogeneous TBEAs were identified across Rwanda's different agro-ecological zones to meet locally-specific smallholders' needs for a set of ecosystem goods and services on the same land. The sustained adoption of TBEAs would be guaranteed if farmers subjectively recognize their compatibility and synergy with sustainable intensification of existing farming systems, supported by favorable institutional conditions.

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