A review of literature shows that work on non-conventional phosphate fertilisers has been done exclusively on sedimentary phosphate rocks. The potential of using novel phosphate fertiliser materials derived from unreactive igneous Dorowa (Zimbabwe) phosphate rock was investigated in a greenhouse experiment. Three phosphate fertiliser materials; (1) finely ground (0.150-mm screen) Dorowa phosphate rock (DPR), (2) partially acidulated Dorowa phosphate rock (PADPR), and (3) a compactcd mixture of

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... PR + triple superphosphate + urea + potassium chloride (DTUK) with half of P from DPR and half from triplc superphosphate (TSP) were made from Dorowa rock and their relative agronomic effectiveness compared with that ol' single superphosphate (SSP) on an acid Hartsells silt loam (pH 4.8) with maize (Zea 111a\s L.) as the indicator crop. Direct application of DPR was found to be ineffective in increasing phosphorus (P) uptake and dry matter yield of maize. The relative agronomic effectiveness of DPR partially acidulated with 50% of the sull'uric acid (HISO,) required for complete acidulation, in increasing Puptake and dry matter yield was 60% and 75%. respectively. The compacted fertiliser product, DTUK, was equally effective in increasing P uptake and dry matter yield as SSP.