中国几种典型农田土壤磷素固液相分配规律

Distribution Law in the Solid-liquid Phase of Phosphorus for Several Typical Soils in China

土壤养分、污染物的生物有效性与其固液相分配规律密切相关。本研究通过室内模拟试验,设置不同的水、热、肥条件和培养时间序列,采用高速离心法对红壤、黑土、潮土、黑垆土、塿土5种典型土壤的磷素固液相分配规律及其影响因素进行了探讨。结果表明,质地不同土壤磷素固液相分配系数(Kd)值差别很大,整体变化趋势是红壤>黑垆土>塿土>黑土>潮土。不同培养条件下土壤磷素固液相分配系数(Kd)值变化特征表现出随着培养时间延长,土壤磷素Kd值增大,土壤磷素生物有效性逐渐降低。水吸力、浓度与之相反,随着水吸力的增加土壤磷素Kd值变小,随着施入磷素浓度的增加而Kd值降低。在整个温度梯度中,当温度处于20￣25℃左右时,土壤磷素Kd值达到最小值,液相磷素含量相对增多,养分有效性增强。

The bioavailability of soil nutrient and pollutants is closely related to their distribution coefficient of solid-liquid phase. In a laboratory incubation experiment, the distribution coefficient in the solid-liquid phase（Kd）in five typical Chinese soils, namely red soil, black soil, fluvo-aquic soil, lou soil and black lu soil, were estimated by ultracentrifugation method. The treatments included different water suction pressure, temperature, incubation period and addition of different concentrations of K2HPO4. The results showed that the Kd-value of different treatments varied widely with different textural soils. The general trend of soil,phosphorus Kd-value was red soil〉black lu soil〉lou soil〉black soil〉fluvo-aquic soil. The Kd value of soil phosphorus increased with incubation period increasing, while decreased with the concentration of K2HPO4 addition and water suction pressure increasing. The bioavailability of available phosphorus in soil also increased gradually with soil phosphorus Kd-value decreasing. However, different temperatures had different effects on soil phosphorus Kd-value. The Kd values of soil phosphorus was lowest and the nutrient availability reached highest at 20-25℃.