The Effect of Calcium Silicate on The Phosphorus Sorption Characteristics of Andisols Lembang West Java

Abstract

The effect of calcium silicate CaSiOJ the phosphorus (P) sorption characteristics were studied in Andisols Lembang. The amount of 0, 2.5 and 5% CaSiOJ (calcium silicate) or 0, 7.5 and 15 g calcium silicate per pot was added to the 300 g (oven-dry weight) soil and incubated for one month. A completely randomized design in double replication was set up. After one month incubation, P sorption and P sorption kinetic experiments were conducted The results of P sorption experiment showed that P sorption data were satisfactorily described by the Langmuir equation. which was used to determine P sorption maxima, bonding energies and P sorbed at 0.2 mg P £"' (standard P requirement). The application of calcium silicate did not affect significantly P sorption maxima but decreased significantly the P bonding energies. Calcium silicate also decreased significantly the standard P requirements. As for P sorption kinetic experiment. the results showed that application of 5% calcium silicate decreased significantly the rate constant of P sorption and P sorbed maximum at given amount of added P. The results suggested that the application of calcium silicate to the Andisols made added P was more available for plant.