DESCRIBING KINETICS OF RELEASED PHOSPHORUS FROM AMMONIUM POLYPHOSPHATE IN CALCAREOUS SOIL

Abstract

"Abstract: Lab experiment had been conducted to study the kinetics of phosphorus in the soil by using a first-order equation with time, 10g of dry soil was mixed with 100mg of the phosphate fertilizers, ammonium polyphosphate (APP), Monoammonium phosphate (MAP) and di-ammonium phosphate (DAP), the mixture placed to 100 ml plastic tube and then 05 N of sodium bicarbonate solution was added to the mixture and then shaken for 5, 30, 60, 120 and 150 minutes, 10 ml had been taken from the mixture and then the released phosphorus was cumulatively measured. The results showed that the highest amount of released phosphorus was achieved in the soil treated with APP fertilizer, at 150 minutes and at L2 level, at 19.71g P.kg-1 . Whereas the highest released phosphorus in the soil treated with MAP fertilizer was 14.93 mg P.kg-1 at 5 minutes and L2. Similarly, the highest amount of soil-released phosphorus treated with DAP fertilizer was 12.42 mg P.kg-1 at 5 minutes and L2. The results also showed that the highest value of releasing speed coefficient (Kd) for soil-released phosphorus in soil treated with APP fertilizer and for the period of the 150 minutes was 3,621 mg P.kg-1 . "