Investigating the impacts of conservation agriculture practices on soil health as key to sustainable dry land maize production systems on semi-arid sandy soils with water tables in the North Western Free State
The current project builds on previous projects funded by the Maize Trust, where the main objective had been the implementation and evaluation of various cultivation practice options for sustainable dry land maize production systems on semi-arid sandy soils with water tables in the north western Free State. These sandy soils developed from Aeolian parent material and were deposited between 1.8 and 5 million years ago on a Palaeolithic surface consisting of poorly drained clayey components of weathered dolerite, mudstone, calcrete and shale. These soils are known for their proneness to wind erosion, inherent compaction problem, low organic matter content and low nutrient and water retention capability. However, the presence of a shallow water table above the Palaeolithic surface, to serve as a water reservoir, contributes to stable crop yields under the highly variable rain fall conditions.
During the evaluation and planning sessions of 12, 22 August and 12 September 2016, several challenges (problems) that still remain in terms of implementing conservation agriculture (CA) practices for sustainable and profitable crop production on sandy soils were identified and prioritized. A shift to practices that improve and maintain soil health was emphasized. On the semi-arid sandy soils of the north western Free State a major portion of the maize yield of South Africa is produced.
Against this background, new and innovative production practices should continuously be tested and implemented on these very unique and fragile soils to enhance and maintain their productivity in view of national food security.