摘要：To understand the behaviour of P in calcareous soils, two diverse lime containing soil series of Peshawar (19 %) and Guliana (4 %), were selected for P adsorption capacity. A 50 mL solution containing 0, 10, 20, 40, 60, 120, 240 and 360 mg P L~(-1) (initially applied P, IPA) was applied to 5 g of respective air-dried soils taken in triplicates in conical flasks and was shaken for 30 h. In strongly calcareous Peshawar soil series, adsorption of P ranged from 85.7 to 1366 mg kg~(-1) which was almost double of the P adsorbed in low lime Guliana soils series at the iso-equivalent level of IPA. Both simple and modified Langmuir and Freundlich models were best fitted (r~2 > 0.95 on average) for the P adsorption pattern in both soils. However, for maintaining 0.2 mg P L~(-1) soil solution, the amount of P2O5 required was 33.51 kg ha~(-1) for Peshawar and 17.47 kg ha~(-1) for Guliana on the basis of adsorption calculation, which is much lower than the amount of P fertilizer as determined in series of field experiments. To maintain the critical soil solution [P], it is recommended to add proportionately more P fertilizers to highly calcareous soil.
