基于单参数Logistic的典型作物相对叶面积指数模型研究

为系统分析叶面积指数变化特征,构建便于实际应用的作物生长模型,在对现有叶面积指数模型参数变化特征分析的基础上,以相对有效积温为自变量,利用修正Logistic模型分析了冬小麦、夏玉米、水稻3种作物相对叶面积指数的增长特征,并确立了模型参数之间的关系。研究结果表明,参数a、b和c与相对有效积温特征值有关,随着c的增大,a逐渐增大、b逐渐减小,且其增大或减小速率均与相对有效积温有关;参数a、c与b之间也存在一定函数关系。基于参数之间的关系,对相对化修正Logistic模型进行了简化,建立了描述冬小麦、夏玉米和水稻3种作物的叶面积指数增长过程的单参数Logistic模型。利用实测资料对模型进行了评估,结果表明,该模型能够很好地模拟相对叶面积指数的增长变化过程。该简化模型参数少、形式简单、便于分析,因此易于应用,对建立其他作物的单参数相对叶面积指数模型具有一定的参考价值。

Relative Leaf Area Index of Typical Crops Based on Single Parameter Logistic Model

Systematic analysis of leaf area index variation characteristics is the basis for constructing a model for practical application of crop growth. The meteorological data and crop leaf area index change data were collected and used for analytical modeling. Based on the analysis of the parameters of existing leaf area index model and the relative growing degree days as the independent variable, the modified Logistic model was used to analyze the growth characteristics of the relative leaf area index of winter wheat, summer maize and rice, and the relationship among the model parameters were established. The results showed that the parameters a, b and c were related to the relative growing degree days eigenvalues. With the increase of c, the value of a was increased and that of b was decreased gradually, and its increase or decrease rate was related to the relative growing degree days, and the rate of change of the three crops was different. At the same time, there was a certain functional relationship between parameters a, c and b. Based on the relationship between parameters, the Logistic model of relative modification was simplified, and a single parameter Logistic model describing the leaf area index growth process of three crops of winter wheat, summer maize and rice was established. The model was evaluated using measured data. The results showed that the single parameter model can simulate the growth process of the relative leaf area index. The simplified model had the characteristics of less parameters, simple form and convenient analysis, so it was easy to popularize and apply, and had certain reference value for establishing single parameter relative leaf area index model of other crops.