ABSTRACT
Background: Phosphorus (P) sorption measurements and lime application are of great importance for the sustainable management of P-adsorptive soils. Aim: Therefore, this study aimed to evaluate soil phosphorus sorption under different land-use types and to assess lime input during phosphorus sorption. Treatments include the land use of enclosures, grazing, cultivated and ensut land. Method: Surface soil samples were collected to study the physicochemical properties of specific soils. Lime was mixed with the soils of cultivated land for 30 days. P sorption was subsequently assessed for all land-use types by equilibrating soil samples in 0.01 M CaCl2 containing 30 mL of KH2PO4 at 0, 10, 20, 30, 40, and 50 mg/L. Result: The results showed that land use type had a significant impact on external P demand (EPR). The Langmuir model proved useful information in explaining P sorption. P fixation ranged from 136 to 731.67 mg.kg-1 according to Langmuir model and EPR values ranged from 45.9 to 398.7 mg P kg-1 soil. Exclusory area soil has high sorption compared to other land-use whereas enset land-uses the lowest sorption. The result of correlation analysis revealed that exchangeable Aluminium and clay had positively correlated on P-sorption maximum and SPR of both models. Conclusion: It was concluded that there was a significant difference among land-use systems of P-sorption and there had an influence of lime on acidic soil to reduce EPR. So black market p-fertilizer utilization is not recommended to study site. Liming also restored the soil chemistry of cultivated land. Nevertheless, field trials were proposed to validate mineralization rates and EPR values in cultivated soils.
