土壤—作物系统钾素动力学模型及其参数研究

KINETIC MODEL AND PARAMETERS OF POTASSIUM IN SOIL-CROP SYSTEM

基于生态学的Lotka Volterra模型 ,在土壤—作物系统中提出一个新的土壤钾素动力学方程。盆栽试验表明 ,该模型能很好地拟合花生一个生长周期内土壤缓效钾和速效钾的动态变化。吸钾量实测结果表明 ,花生不同生育期吸钾量符合Logistic模型。结合上述 2个模型 ,分别求出矿物钾最大释放速率常数Kmm、缓效钾最大释放速率常数Krm和速效钾最大供钾速率常数Kam。相关分析表明 ,Kam与花生当季吸钾量、生物学产量和荚果产量以及Krm与花生当季吸钾量有显著水平以上的对数正相关。Krm和Kam可作为评价土壤当季供钾能力的速率指标。

Summary This paper puts forward a new kinetic model of potassium based on Lotka Volterre model in ecology. A pot culture experiment was conducted showing that with the model, dynamic trends could be simulated of readily available potassium and slowly available potassium of soil in the growing period of peanut. The test of potassium absorption indicated that the change in K absorption in different growing periods of peanut accorded with the Logistic model. From the above two models, constants of the maximum release rates for mineral K ( K mm), slowly available K ( K rm) and rapidly available K ( K am) could be got. Correlation analyses showed that the relationship was obvious of K am with K absorption of the current crop, its biomass yield and its peanut yield, and between K rm and K absorption by the current crop. Therefore, K am and K rm could be used as index of potassium release rates in soil.