研究了我国几种代表性土壤(包括黄壤、红壤、砖红壤性土、黄棕壤、黑土和褐土)磷酸根释放的动力学特性。结果表明:无论在 0.02M KCl溶液中还是存在竞争性阴离子(0.001M)柠檬酸根)条件下,磷酸根的释放都明显存在快反应和慢反应两个阶段。快反应在1—4小时内基本完成,慢反应延续到20小时甚至更长时间。但除砖红壤性土在慢反应过程中仍释放出一定数量的磷外,其余供试土壤慢反应释出的磷极少。供试土壤磷酸根释放量随时间变化与Langmuir动力学方程最为吻合Elovich方程其次,一级动力学方程相对较差。在竞争性阴离子存在条件下,土壤释放磷酸根的速率和数量都显著高于单纯的0.02M KCl溶液。鉴于在实验条件(pH7.0)下,两种平衡溶液中铁、铝和钙的浓度都很低,不足以产生磷酸盐化合物的沉淀和溶解反应;并且磷酸根释放随时间变化的趋势在两种溶液中十分一致,很快达成平衡,故可以认为土壤中磷酸根释放到溶液中的机制主要是吸附态磷酸根的解吸和竞争性阴离子的配位交换作用,后者在根际区可能是重要的。 The kinetic characteristics of phosphate release from several representative soils in China, including yellow soil, red soil, brick loamy soil, yellow brown soil, black soil and cinnamon soil, were studied. The results showed that the phosphate release obviously existed in two stages of fast reaction and slow reaction in both 0.02M KCl solution and competitive anion (0.001M) citrate. Fast response in the 1-4 hours basically completed, slow reaction extended to 20 hours or longer. However, in addition to brick red loam soil in the slow reaction process is still released a certain amount of phosphorus, the remaining test soil slow reaction to release very little phosphorus. The changes of soil phosphate release with the time agree well with the Langmuir kinetic equation Elovich equation Second, the first-order kinetic equation is relatively poor. In the presence of competitive anions, the rate and amount of phosphate released by the soil were significantly higher than pure 0.02M KCl solution. Given that the concentrations of iron, aluminum and calcium in the two equilibrium solutions were low at experimental conditions (pH 7.0), they were not enough to produce precipitation and dissolution reactions of the phosphate compounds; and that the tendency of phosphate release over time varied between two The solution is very consistent and quickly balanced, so that the mechanism by which phosphate is released into solution in the soil is mainly the desorption of adsorbed phosphate and the coordination exchange of competing anions, which may be important in the rhizosphere of.