摘要： 应用³²P同位素动力学方法对7种石灰性土壤磷库进行了标定。通过测定加入土-水体系中不同时间残留于溶液中的³²P活度而建立的动力学模型，可以获得固液界面磷的交换率Km、磷的平均交换通量Fm、磷酸根离子在溶液中的平均滞留时间Tm以及第1分钟内可交换磷量（E₁）等参数，并且可以对土壤磷库进一步区分为不同时间内可交换磷库。将上述参数与土壤同位素交换磷（E值）、同位素稀释法有效磷（A值）以及Olsen磷进行比较，表明同位素动力学参数与上述传统方法测定的有效磷量以及植物吸磷量均有极显着的相关关系，可用于对石灰性土壤的有效磷库进行标定。

关键词: 石灰性土壤, 磷素, 同位素, 动力学

Abstract: The phosphorus pools of seven calcareous soils were characterized by using ³²P isotope kinetic approach. Through the determination of residual radioactivity in soil solution at different time after the introduction of the isotope to the steady soil-water system, a well-defined isotope kinetic model was obtained by which the mean sojourn time of phosphate in solution (T_m), the mean exchange rate(K_m),and the mean flux (F_m)of phosphate ions between solid and solution can be calculated. Other parameters such as the exchangeable P of the first minute(El), P in various pools that could be exchanged with solution phosphate ions at different period of time were also calculated. These parameter were further compared with other conventional P indices such as E value,A value and OIsen-P as well as ryegrass uptake of P. Results indicated that the above parameters and indices were highly correlated with one another. It is suggested from the study that the isotope kinetic approach could be used to characterize soil available P pools.

Key words: Calcareous soil, Isotope, Kinetics, Phosphorus

中图分类号: 

• S153