Phosphorus Mobility Through Soil Increased with Organic Acid-Bonded Phosphorus Fertilizer (Carbond® P)

Phosphorus fertilizer is critical to crop production but inefficiently absorbed and consequently linked to surface water pollution. Phosphorus mobility was measured on three soils using 0.18m soil columns treated with Carbond (R) P (CBP, 7-24-0), ammonium polyphosphate (APP, 10-34-0) and monoammonium phosphate (MAP, 11-52-0) applied either by mixing thoroughly or in concentrated bands at rates of 20 and 30kg P ha(-1). Mobility of P was measured in leachate collected 24, 48, 110 and 365 d after fertilization (daf). Carbond (R) P produced the highest total P leachate values over 365 d study period compared to MAP or APP for both mixed and band applications. On individual days, CBP generally allowed more soluble P leachate than MAP or APP up until 110 daf (one exception) but not at 365 daf. Higher solubility of P with CBP explains higher P uptake by plants from soils and could reduce total P applications to crops.