石灰性土壤与磷酸盐的反应及吸持态磷的同位素交换性

本文研究了种石灰性土壤（Ｌｏｕ土）与磷酸盐的反应动态过程，短期反应的等温吸附研究表明，在低磷浓度下，以吸附反应机制为主，吸持态磷的同位素交换性随着吸持量的增加而增加；在高磷浓度下，以形成磷酸盐的沉淀反应机制为主，吸持态磷的同位素交换性随着反应时间的延长和吸持量磷数量的增加而了降低。认为在低施磷水平下，土壤中铁，铝氧化物对磷的吸持起重要作用。本文还探讨了在长期（２６０天）恒温恒湿培养过程中，土壤可溶

SORPTION AND EXCHANGEABILITY OF IN CALCAREOUS SOIL

Studies on the reaction between phosphate and a calcareous soil in terms of sorption isotherms indicated that at low phosphat concentrations, phosphat was adso rbed on the surface of soil particles; the exchangeability of sorbed phosphate increased with amount of phosphate sorbed suggested that iron and aluminium oxides had an important role in phosphate adsorption in the soil. At high phosphate concentrations, precipitation occured due to formation of calcium phosphate, and the exchangeability of sorbed phosphate declined with the time of reaction and the amount of phosphate sorbed. Kinetic changes of soluble-P, ³²P exchangeable-P and Olsen-P in the soil with and without phosphate addition were also studied through a long period of incubation (up to 260 days) experiment, fractionation of phosphorus in the ³²P labeled soil was conducted finally.