不同提取方法土壤非交换性钾释放动力学及其速率的研究

采用Ca2+饱和土壤的 0.50molL-1硝酸、0.0 1molL-1草酸和氢质阳离子交换树脂恒温连续提取法 ,利用Elovich和二级动力学模型 ,结合生物吸钾试验 ,研究探讨了描述土壤非交换性钾释放及其速率较为理想的连续提取法及其动力学模型。研究结果表明 ,氢质树脂提取法的Elovich模型描述非交换性钾释放及其速率的效果较为理想 ,拟合方程的相关系数达极显著水平(r =0.982～ 0.996 ) ;不同时间非交换性钾累积释放量的计算值与实测值的标准差最小 (S =1.335～2.480 ) ;通过速率方程计算的不同时间非交换性钾释放速率与黑麦草吸收的非交换性钾数量的相关性也最为密切 (r =0.944～ 0.963) ,故氢质阳离子交换树脂连续提取法结合Elovich模型是描述土壤非交换性钾释放及其速率较为理想的组合方法。以伊利石为主的 2、3和 8号土壤非交换性钾释放速率明显高于其它以高岭石或蒙脱石为主的供试土壤

Study on the kinetics and rate of soil nonexchangeable K release by three various extraction

The better extracting method and kinetic model for describing the release and rate of soil non exchangeable K were discussed with Elovich, Second order kinetic models by 0.50 mol· L^-1 HNO₃, 0.01 mol·L^-1 oxalic acid and H resin successive extraction under constant temperature and pot exhaustion of ryegrass. The results showed that Elovich equation fitted by the data of H resin extraction perfectly described the release and rate of non exchangeable K. The correlation coefficients of the equations came up to the most significant standard (r=0.982～0.996), and standard errors between the calculations of non exchangeable K releasing capacities by the equations and the estimates by H resin extraction were only 1.35～2.48. The releasing rates of non exchangeable K at various time calculated by Elovich rate equation of H resin extraction were most significantly correlated with the amounts of non exchangeable K absorbed by ryegrass (r=0.944～0.963). It was suggested that Elovich model and H resin extraction could be used as perfect model and method to describe the release and rate of soil non exchangeable K. The results also showed that the release rates of non exchangeable K in illitic soils, including soil 2, 3 and 8, were much higher than those in kaolinitic and montmorillonitic soils.