Integrated systems research for sustainable intensification of smallholder agriculture

In sub-Saharan Africa (SSA), increases in yields of the major crops in smallholder farming systems have failed to match population growth, with increased production resulting rather from agricultural area expansion (Worldbank, 2007), very often at the expense of the natural resource base, such as carbon-rich and biodiverse forest land (e.g. Gockowski and Sonwa, 2011). Intensification of smallholder agriculture is a must under high population densities but also desirable in less populated areas in order to protect natural ecosystems. Smallholder farming communities and systems in SSA are heterogeneous, both at the community and farm level, driven by varying and often limited access for production resources (land, labour, capital) (Tittonell et al., 2010). At the community level, variable resource endowments and production objectives are often conceptualized through the construction of farm typologies. At farm level, preferential management of specific plots within a farm has resulted in within-farm soil fertility gradients, often with soils of higher fertility near the homestead, and more degraded soils towards the outer limits of the farm. For many households and regions, agriculture alone will not be able to provide rural populations with adequate livelihoods due to limited farm size and access to land (Harris and Orr, 2014; Jayne et al., 2014). Besides heterogeneity at farm and community level, enabling conditions for intensification, often expressed as access to agro-inputs, markets, and credit, quality of rural infrastructure, or conducive policies, also vary considerably. Intensification of smallholder farming systems will thus require co-learning among research, development, and private sector actors for the tailored integration of both technical and institutional innovations (Giller et al., 2011; Coe et al., 2014)