耕作土壤的非交换性 K释放速率

采用氢质阳离子交换树脂连续提取法 ,结合生物吸 K实验 ,探讨了利用零级动力学、一级动力学、Elovich和抛物线模型描述耕作土壤非交换性 K释放效果、释放速率差异及其与非交换性 K有效性的关系 .结果表明 ,利用 Elovich模型拟合土壤非交换性 K释放方程的相关系数为 0 .982 * * - 0 .996 * * ,达极显著水平 ,且非交换性 K累积释放量的模型计算值与实测值间的标准差仅为 1.35- 2 .4 8,而零级、一级和抛物线模型拟合方程的相关系数相对较低 ,标准差则为 Elovich模型的 5- 9倍 .Elovich模型计算的不同时间土壤非交换性 K释放速率与黑麦草非交换性 K吸收量及生物总量呈极显著或显著正相关 ,表明利用 Elovich模型描述耕作土壤非交换性 K释放速率较为理想 .以伊利石为主的土壤非交换性 K释放速率 ,尤其是 2 4 h之前的释放速率 ,明显高于以高岭石或蒙脱石为主的土壤

Releasing rate of nonexchangeable K in some cultivated soils

Releasing characteristics of nonexchangeable K in some cultivated soils were tested by H resin successive extraction and pot exhausion of ryegrass, and described with zero order, first order, Elovich and parabolic kinetic models. The release rate of nonexchangeable K and correlation between the rate and the availability of nonexchangeable K were discussed. Results showed the range of correlation coefficients of the K releasing equations described by Elovich model was 0.982 ** -0.996 ** , and the range of standard errors between the calculation of K releasing capacity from the equations and estimated by H resin extraction was only 1.35-2.48. The correlation coefficients described by zero order, first order and parabolic models were much lower, and their standard errors were 5-9 times as high as those of Elovich model. The release rates of nonexchangeable K at various time calculated by Elovich model were very significantly or remarkably correlated with the amounts of nonexchangeable K absorbed by ryegrass and the dry biomass yields of ryegrass. It suggested that the Elovich model could be used as a better equation to describe the release rate of soil nonexchangeable K. The results also showed the releasing rates of nonexchangeable K in illitic soils, especially the rates before 24 h, were much higher than those in kaolinitic and montmorillonitic soils.