Conservation agriculture is a farm land management strategy that focuses on the preservation of soil moisture and prevention of soil erosion through reduced tillage, permanent organic soil cover, and the use of crop rotation or intercropping.
Conservation agriculture is widely promoted as a Climate Smart Agriculture (CSA) which pursues development, climate mitigation and adaptation goals simultaneously. As such, our CA research directly contribute to the wider theme of Climate Compatible Development (CCD).
It is an approach that is increasingly promoted within agricultural development and food security work in sub-Saharan Africa (eg, Africa CSA Alliance), but many of the success claims attached to it are built on an incomplete evidence base.
A new programme of research led by the Sustainability Research Institute, in partnership with the Lilongwe University of Agriculture and Natural Resources (Malawi) and Copperbelt University (Zambia), looks to identify and address knowledge gaps relating to this much-heralded ‘climate smart’ agricultural technology in southern Africa.
Determining context appropriate conservation agriculture strategies and understanding the role, performance, and barriers to the adoption of the technology within farming systems that are subject to resource constraints, local and uncertain agro-ecological conditions, economic and political risks, and social and cultural dynamics, requires interdisciplinary insight. Conservation agriculture represents a case study of the broader challenges of achieving appropriate and climate compatible agricultural development. We are involved in coordinating and working with a network of organisations within Zambia and Malawi to offer multi-perspective insights into these complex challenges.
In May 2014, a workshop was held in Lilongwe that brought together representatives of 19 organisations involved in research, practice and policy to discuss knowledge gaps and begin to plan research programmes.
<p>The project goal is to understand the impacts of the 2015-16 El Niño on cropping choices, yields and post-harvest losses of CA and non-CA farmers in South East Kenya and southern Malawi. It will assess the contributions that CA practices have provided to the climate-resilience of smallholder livelihoods during variable conditions in the 2015-16 El Niño event and through comparisons with previous similar events and proceeding contrasting climate extremes.</p><p>Aim:</p><p>To better understand under what farming system conditions CA improves the resilience of smallholder production through extreme climate conditions.</p><p>Objectives:</p><ul> <li>To analyse whether farmers practicing CA can better maintain their crops compared to those not practicing CA under above average and below average rainfall extremes.</li> <li>To compare farmers’ experiences of the El Niño of 2015-2016 with experiences of previous El Niño events in these contexts.</li> <li>To analyse the impact of climatic and farming system conditions associated with El Niño on incidence of crop pest damage.</li> <li>To evaluate how the 2015-16 El Niño event will affect farmer decision-making on cropping, land management and post-harvest handling in the subsequent 2016-17 growing season.</li></ul><p>We will test the hypothesis that smallholder farm-plots under CA practices are likely to sustain or increase their yields and livelihood security during the 2015-16 El Niño event compared to non–CA farm-plots. Testing this hypothesis and answering these research questions will help to quantify the benefits of CA practices has in being ‘climate-smart’ and improving the resilience of crop production and smallholder livelihoods to climatic stresses and shocks.</p>
<p>Understanding the interactions between drought and heat stress, soil texture and crop management is critical if we are to understand and predict the adaptive capacity of conservation agriculture. The SRI CA group are leaders in this arena we have recently published a novel synthesis which integrated published CA yield datasets (supplemented with data provided by Christian Thierfelder, CIMMYT) with global soil and historical climate datasets.</p><p>Our headline findings were that that conservation agriculture enhances the adaptive capacity of maize production in sub-Saharan Africa under drought and/or heat stress. However, in very wet seasons and on clay-rich soils, CA yields less compared to conventional practices.</p><p>In our publication we used meta-regression to explore four key questions:</p><p>(1) Does the relative yield performance of CA improve with increasing drought and temperature stress? (relative meaning as compared to a conventional control).</p><p>We found that the relative maize yield performance of CA improves with increasing drought severity or exposure to high temperatures.</p><p>(2) Do the effects of moisture and temperature stress interact?</p><p>Yes! we found a significant interaction of moisture and heat stress on CA performance. CA always performs well in conditions of average rainfall to drought, but heavy rainfall reduces its benefits. The response to heatstress is complex and affected by soil type (Figure 1).</p><p>(3) Are the effects of moisture and temperature stress are modified by soil texture?</p><p>Yes! As mentioned above, we found the amount of clay in soils changed the effect of moisture and heat stress on CA performance. On soils with lower clay contexts, more silty or sandy soils with better drainage, CA appears to cope better with heat stress than CP and heavy rainfall has a less negative effect on CA performance. Soils containing a lot of clay are less favourable for CA if rainfall is high, presumable because of increased waterlogging, and CA appears no more resilient to heat stress than CP.</p><p>(4) Do crop diversification, fertilizer application rate, or duration of no-till enhance CA performance under climate stress?</p><p>This was complicated. First we found increasing nitrogen application rates did not improve the relative performance of CA under high heat stress. Second we found crop diversification did not notably improve CA performance, but did increase its stability with heat stress. Third we did not find a statistically robust effect of no-till duration, but more data from long-term studies is required to explore this properly.</p>
Publications and outputs
Steward, P. R., A. J. Dougill, C. Thierfelder, C. M. Pittelkow, L. C. Stringer, M. Kudzala and G. E. Shackelford (2018). "The adaptive capacity of maize-based conservation agriculture systems to climate stress in tropical and subtropical environments: A meta-regression of yields." Agriculture, Ecosystems & Environment 251(Supplement C): 194-202. www.sciencedirect.com/science/article/pii/S016788091730419X
Dougill, A.J., Whitfield, S., Stringer, L.C., Vincent, K., Wood, B.T., Chinseu, E.L., Steward, P., Mkwambisi, D.D. (2017). Mainstreaming Conservation Agriculture in Malawi: knowledge gaps and institutional barriers. J. of Environmental Management, 195, 25-34.
Sutcliffe, C., Dougill, A.J., Quinn, C.H. (2016). Evidence and perceptions of rainfall change in Malawi: Do maize cultivar choices enhance climate change adaptation in sub-Saharan Africa? Regional Environmental Change, 16; 1215-1224
Whitfield, S., Dougill, A.J., Dyer, J.C., Kalaba, F.K., Stringer, L.C. (2015). Critical reflection on knowledge and narratives of Conservation Agriculture. Geoforum, 60, 133-142.
Conservation agriculture workshop report
Informing Climate Smart Agriculture in Lilongwe district: A proposal to study resilience, pests and disease in the Chitedze long-term Conservation Agriculture trial