Assessing the contributions of Conservation Agriculture to building resilience to drought
Conservation Agriculture (CA) is based on three principles: minimum mechanical disturbance of the soil through reduced tillage, maintenance of a permanent organic cover using crop residue mulches, and practice of legume-based crop rotations. The combination of residue retention and reduced tillage can improve soil structure and water storage and regulate soil moisture and temperature fluctuations associated with the effects of climate change and variability.
CA has been advocated as a major contributor to Climate Smart Agriculture (CSA).
- Offers immediate gains in crop productivity and farm incomes
- Contributes to the mitigation of greenhouse gasses by sequestering soil carbon
- Improves the resilience of farming systems to rising temperatures and more variable rainfall associate with climate change.
- Improvements of water use efficiency particularly contribute to resilience in the face of drought.
Recent studies have shown that CA has been successful in increasing yields in some areas of Zambia and Zimbabwe (FAO, 2011). However, the benefits of CA are diverse, and depend to a large extent on the nature of the agroecosystem under consideration, and how well CA technologies are adapted to the local environmental and cultural conditions (Chivenge et al., 2007; Giller et al., 2009; Mafongoya et al., 2016). Overall adoption rates have been lower than expected, and in some areas, rates of dis-adoption have been high (Giller et al., 2009). While national rates of CA adoption remain low, there is evidence that many farmers are continuing to apply CA practices because they perceive significant benefits from these investments. This includes the adoption of planting basins and mechanical ripping in Southern Africa.
Some key questions that still need answers
- What are the contributions of specific CA techniques to crop productivity as well as the contribution of additional crop management practices which are not generally categorized as conservation agriculture techniques? The former include the tillage technique, the application of mulch and the crop rotation. The latter include the time of planting, variety choice, level and type of fertilizer application, the timeliness and level of weed control and environmental factors such as soil type.
- Why neighbouring farm households with similar agro-climatic and market environments have made different technology adoption decisions?
- Do these perceptions change in drought years?
The research report is the culmination of Vuna-commissioned cross-country research in Zambia and Zimbabwe to assess the contribution of Conservation Agriculture to build the climate resilience of smallholder farmers.