陕西几种土壤非交换钾释放动力学研究

A Study on the Kinetics of NonexchangeablePotassium Release from the Soil in Shaanxi

采用Ｈ饱和树脂吸收法研究了陕西６种土壤非交换钾释放的动力学性质。结果表明：①黄土性土壤非交换钾释放量和释放速度与风砂土类似，远高于暗棕壤；②供试土壤不同时段的非交换钾释放速度不同，０～７２ｈ的释放速度远大于７２～９１２ｈ的钾释放速度；③供试土壤非交换钾释放过程在９１２ｈ内用直线方程描述拟合最好；④供试土壤非交换钾释放速率常数Ｂ主要决定于粘粒与缓效钾含量。常数Ｂ和非交换钾释放速度Ｖ可用于土壤供钾能力评价。

The kinectics characteristics of the nonexchangeable potassium release from the soil in Shaanxi is investigated with the Hsaturated resin absorbing method.The results indicate that: The quantity and velocity of the nonexchangeable potassium release from the loess soils are alike to sand soil,and are higher than the dark brown forest soil. The velocity of the nonexchangeable potassium release from the soil tested is different at different stages of time.The velocity of the nonexchangeable potassium release is more highly marked in 072 hours than in 72912 hours. The process of the nonexchangeable potassium release from the soil tested in 912 hours can be well described with linear equation. The constant B rate of the nonexchangeable potassium release from the soil tested is controlled by the content of clay and slowly available K.The contant B rate and the average velocity V of nonexchangeable potassium release can be used for the evaluation of the capability of soil supporting potassium to plant.