Abstract

Phosphorus is a critical nutrient for crop production. The soil phosphorus deficit in sub-Saharan Africa is one of the most important constraints on crop productions. Resulting from the high phosphorus fixation capacities of highly weathered acidic soil coupled with the relatively low total phosphorus, the impact of this deficit is particularly pronounced in the case of rice cultivation. Phosphate rock is a promising alternative to water-soluble phosphorus fertilizers, but its low solubility has so far prevented its widespread adoption in the region. This study examined the results of a direct application effect of phosphate rock produced in Burkina Faso phosphate rock (BPR) on rice yields in on-farm trials conducted in the Guinea savannah and Equatorial forest zones, and on a phosphate rock decision support system (PRDSS) model. We initially hypothesized that BPR direct application will show little effect on rice yield due to its low solubility as same as previous studies. However, our study found that direct application of BPR has an effect on rice grain yield comparable to that of chemical water-soluble phosphate fertilizer, although according to PRDSS simulations, direct application of BPR had little effect compared to the effect of water-soluble phosphate fertilizers. The recognition of BPR effect on rice yield can enhance rice cultivation along with the aspect of usage of indigenous phosphorus resource in sub Saharan Africa (SSA).

Key words: Phosphate rock, direct application, phosphate rock decision support system (PRDSS), lowland rice, Ghana.