What is the importance of the mineral and organic forms of unavailable phosphorus in the soil?
About half of the unavailable phosphorus in the soil is found in each form. Microbial decomposition of organic matter releases the phosphorus in an available form. Chemical weathering of phosphate minerals releases the phosphorus into the soil in an available form. Because of the high microbial activity in most soils, more phosphorus is made available each year from organic sources compared to mineral sources.
