The Phosphorus Cycle The Phosphorus Cycle Animal Animal Sources Sources Animal Animal Sources Sources Biosolids Biosolids Biosolids Biosolids Plant Residues Plant Residues Plant Residues Plant Residues F ertilizer Fertilizer F ertilizer Fertilizer Adsorption Adsorption Immobilization Immobilization Leached P Leached P Crop Harvest Crop Harvest Plant P Plant P Soil Organic Matter Soil Organic Matter Secondary Minerals & Compounds Secondary Minerals & Compounds Desorption Desorption Precipitation Precipitation Dissolution Dissolution Mineralization Mineralization Solution P Solution P Runoff & Erosion Runoff & Erosion Primary Minerals Primary Minerals Weathering Weathering