The effect of soil properties and level of fertilizer application on the dissolution of sechura rock phosphate in some soils from Brazil, Colombia, Australia and Nigeria

Abstract

The extent and rate of dissolution of Sechura rock phosphate in 30 soils from Brazil, Colombia, Australia and Nigeria were measured. There was an initial rapid dissolution within 1 day, and this was followed by slower dissolution up to 124 days. For all soils an increase in the level of rock phosphate resulted in a smaller proportion dissolving. After 31 days, the percentage dissolved differed widely between soils and for rock phosphate application levels of 0.34 and 34 mg g-1 soil ranged over 0-100%, and 0-21% respectively. Pyrophosphate and oxalate-extractable iron and aluminium were important soil properties for predicting the amount of rock phosphate dissolution; pH, organic carbon, silt content and exchangeable calcium were subsidiary predictive properties for some soils.