Conservation Agriculture in African Rainfed Small Scale Farming Systems: The Agnostic View.

Conservation agriculture (CA) has received a lot of attention over the last few decades and has become the topic of a heated and polarized debate in Africa. On one hand, ‘believers’ are promoting CA with a religious zeal, whilst on the other hand, ‘heretics’ are questioning the suitability of CA for the majority of African smallholders. In this paper, we present an intermediate ‘agnostic’ view. First, we acknowledge the low and slow adoption of CA in Africa. We partially attribute this to the promotion of CA in environments lacking necessary preconditions - e.g. availability of alternative to tillage for the control of weeds – and to resource-constraints at farm-level – e.g. limited labour available around peak time and limited capital to invest in herbicides. We also attribute this to a rigid approach focusing on technological components – i.e. surface mulching, minimum tillage and rotation/intercropping – rather than processes, with the outcome of often limited or ambiguous benefits.  Using empirical field evidence and socio-economic data from Eastern and Southern Africa, as well as outputs from crop simulation models and farm-scale bio-economic models, we demonstrate (1) that the short-term impact of CA depends on complex interactions between soil texture, slope, rainfall, tillage, surface mulch, and N fertilization; and (2) that unpacking CA would benefit a far greater number of smallholder farmers than its rigid application as a holistic approach. This calls for a pragmatic, flexible and site-specific approach to CA.