Farmers inspect a demonstration plot during a conservation agriculture field day near Songani in Zomba district, Malawi. Photo: P. Lowe/CIMMYT
Smallholder farmers throughout southern Africa continue to be constrained by high rainfall variability and lack of access to agricultural inputs, resulting in poor harvests and challenges from food shortages to malnutrition.
Conservation agriculture (CA) practices such as minimal soil disturbance, permanent soil cover and the use of crop rotation have been promoted as a useful set of tools that could improve farmer resilience to these challenges. However, matching CA practices to agro-ecological and socioeconomic conditions remain contentious.
In a recent study conducted by scientists at the International Maize and Wheat Improvement Center (CIMMYT) with other partners, empirical data and results from a cropping system model were combined to quantify benefits and trade-offs, in terms of sowing opportunity, yield, and yield variability, from adopting CA practices in southern Africa.
Simulated results in the study showed that some practices like direct seeding and farming in a basin planting system prepared late and at the onset of the rains improved timeliness of operations, and enabled earlier planting across all locations compared to conventional systems. Mechanized CA systems also offered farmers potential flexibility on when to plant.
However, timely planting of CA systems did not translate into higher yields when carried out during periods of high rainfall variability. Yield benefits of early plantings in CA were only apparent in Zimbabwe.
The authors conclude that draught power mechanized CA systems offer farmers the capacity to plant closer to optimum dates, and that model-generated optimum planting dates could be used to provide farmers with site-specific planting date recommendations.
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