Conservation agriculture and its impact on soil quality and maize yield: A South African perspective

• This review showed that CA in Southern Africa is limited to few commercial farmers.
• Research on peer-reviewed literature of different agro-ecozones is scant.
• CA improves soil quality and water use efficiency especially in water-scarce regions.
• Yield improvements were reported by farmers adopting CA.
• More research is in different agroecological zones is required.

Sub-Saharan Africa is faced with the challenge of improving current food security on highly degraded land. At the same time, the region has to develop strategies to ensure future food security for the increasing population under worsening climate change. Conventional tillage (CT) has for many years resulted in the deterioration of soil quality through depletion of soil organic matter. This review of literature provides an overview of the impact of conservation agriculture (CA) on soil quality with particular emphasis on key soil physical, chemical and biological properties. This paper also discusses impact of CA on yield, highlighting South African research gaps since the adoption is still very low in the country. The review of numerous studies indicated that soil quality and yield improvements are possible in CA although some negative results have also been reported under contrasting environments. Yield under CA were recognised to be resilient to seasonal rainfall variability compared with CT because of its ability to conserve water. CA is particularly relevant to the South African maize production given high levels of soil degradation, water scarcity and low soil fertility status. This review of literature demonstrated that CA can have substantial positive environmental, financial, social and health benefits for South Africa and the world. However, more research on CA is required from different agroecological zones and socio-economic contexts since maize is the biggest produced crop in South Africa.