Department of Soil Science and Agricultural Chemistry, Agricultural College and Research Institute, Tamil Nadu Agricultural University, Madurai - 625 104, India.
Reactivity of phosphate rock determines its potential as a direct fertilizer. The effectiveness of phosphate rock relative to soluble P fertilizer will vary from source to source depending upon the mineralogy and chemistry of each rock as well as the influence of soil, crop, environment and management factors. Relative effectiveness is mainly used for comparison of two or more P sources. This review paper comprises chemical reactivity, dissolution of phosphate rocks and comparison of effectiveness of P sources.
