The agronomic effectiveness of Daoui phosphate rock in Brazilian soils

Brazilian soils are acidic in nature and deficient in plant-available phosphorus. Because of these soil characteristics, the alternative of applying reactive phosphate rocks (PRs) to soluble fertilizers has become important. About 300,000 tonnes of phosphate rock was applied in the year 2000. Since 1989 unground Gafsa and Arad reactive PRs have been available in the Brazilian fertilizer market. In 1994 the Brazilian Official Agriculture Research organizations began trials with Daoui PR from Morocco to compare its reactivity and plant effectiveness with the traditional PRs and triple superphosphate (TSP). Two types of trials have been conducted during the last 7 years in different regions of the country with different annual crops. The results of these trials demonstrate that Daoui PR has a similar agronomic effectiveness to Gafsa and Arad PRs.