Comparison of Seven Kinetic Equations for K Release and Application of Kinetic Parameters

L(U) Xiao-Nan; XU Jian-Ming; MA Wan-Zhu; LU Yun-Fu

摘要

Corn field experiments with two treatments, NP and NPK, where N in the form of urea, P in the form of calcium phosphate, and K in the form of KC1 were applied at rates of 187.5, 33.3, and 125 kg ha-1, respectively, on soils derived from Quaternary red clay were conducted in the hilly red soil region of Zhejiang Province, China. Plant grains and stalks were collected for determination of K content. Seven equations were used to describe the kinetics of K release from surface soil samples taken before the corn experiments under electric field strengths of 44.4 and 88.8 V cm-1 by means of electro-ultrafiltration (EUF) and to determine if their parameters had a practical application. The second-order and Elovich equations excellently described K release; the first-order, power function, and parabolic diffusion equations also described K release well; but the zero-order and exponential equations were not so good at reflecting K release. Five reference standards from the field experiments, including relative grain yield (yield of the NP treatment/yield of the NPK treatment), relative dry matter yield (dry matter of the NP treatment/dry matter of the NPK treatment), quantity of K uptake in the NP treatment (no K application), soil exchangeable K, and soil HNO3-soluble K, were used to test the effectiveness of equation parameters obtained from the slope or intercept of these equations. Correlations of the ymax (the maximum desorbable quantity of K) in the second-order equation and the constant b in the first-order and E lovich equations to all five reference standards were highly significant (P ≤ 0.01). The constant a in the power function equation was highly significant (P ≤ 0.01) for four of the five reference standards with the fifth being significant (P ≤ 0.05). The constant b in the parabolic equation was also significantly correlated (P ≤ 0.05) to the relative grain yield and soil HNO3-solublc K. These suggested that all of these parameters could be used to estimate the soil K supplying capacity and the crop response to K fertilizer.

机译：玉米田间试验采用NP和NPK两种处理方法，其中分别以187.5、33.3和125 kg ha-1的比例施用尿素形式的N，磷酸钙形式的P和KC1形式的K，在中国浙江省丘陵红壤地区分别对第四纪红黏土进行了土壤研究。收集植物的谷粒和茎，以测定钾含量。七个方程用于描述在玉米实验前通过电场超滤（EUF）在44.4和88.8 V cm-1的电场强度下从表层土壤样品中释放钾的动力学，并确定它们的参数是否实用应用。二阶方程和Elovich方程很好地描述了K的释放。一阶，幂函数和抛物线扩散方程也很好地描述了K的释放;但是零阶方程和指数方程不能很好地反映钾的释放。田间试验的五个参考标准，包括相对谷物产量（NP处理的产量/ NPK处理的产量），相对干物质产量（NP处理的干物质/ NPK处理的干物质），钾吸收量在NP处理（不施用K）中，土壤可交换K和土壤HNO3可溶性K用于测试从这些方程的斜率或截距获得的方程参数的有效性。二阶方程中的ymax（K的最大可解吸量）与一阶方程和E lovich方程中的常数b与所有五个参考标准的相关性非常显着（P≤0.01）。对于五个参考标准中的四个，幂函数方程中的常数a高度显着（P≤0.01），第五个参考标准中的常数a显着（P≤0.05）。抛物线方程中的常数b也与相对籽粒产量和土壤HNO3-可溶性钾显着相关（P≤0.05）。这表明所有这些参数都可用于估算土壤钾素供应能力和作物对土壤钾素的响应。钾肥。

Comparison of Seven Kinetic Equations for K Release and Application of Kinetic Parameters

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