Abstract
Local phosphate rock use in sub-Saharan Africa (SSA) has immense potential to enhance African crop productivity. The effects of Kodjari phosphate rock direct application (PRDA) were studied in a rain-fed lowland rice (Oriza Sativa L.) fields with two levels of N applications, under different duration of submergence affected by seasonal flooding in the Sudan Savana of Burkina Faso. During the first year, PRDA with 90 kg N ha-1 did not affect rice yields whereas PRDA with 30 kg N ha-1 resulted in 91% yield obtained by using triple super phosphate (TSP). However, in the following season, successive PRDA indicated comparable effects as those of TSP application with both 30 and 90 kg N ha-1. Although TSP application indicated higher residual effects than that of PRDA, our investigation identified capital P replenishment by PRDA in the rain-fed lowland-rice cultivation area in the Sudan Savanna. Longer submergence duration resulted in higher PRDA effects. In conclusion, the high potential of PRDA on lowland rice was demonstrated in the Sudan Savanna zone. Considering previous studies, PRDA can be regarded as an effective technical option for lowland rice cultivation in the SSA. Although the effects of initial PRDA might have been depressed under water-limited conditions, it can contribute to improvement of soil P availability with replenishment of capital P for enhancing lowland rice production in SSA.
