养分(磷)吸收机理模型的应用研究──Ⅱ.模型参数的敏感性分析

Studies on the Applications of Mechanistic Nutrient (P) Uptake Models─Ⅱ. The Sensitivity Analysis of Model Parameters

采用Claassen的养分吸收机理模型探讨了玉米与大豆幼苗磷吸收过程中的参数敏感性，结果表明：在一般土壤与施肥条件下，玉米与大豆幼苗吸收磷的高度敏感性参数或重要限制因素为根系伸长速率与根半径；在相同土壤供磷条件下，供试大豆幼苗根系的磷摄取能力远低于玉米幼苗根系的磷摄取能力，其原因归结于两者在根系最大养分流Imax与根系伸长速率K两个敏感性参数上的差异；玉米与大豆幼苗磷吸收过程中三种根毛参数的敏感性均较低，这主要与土壤供磷水平较高有关；土壤含水量在玉米幼苗磷吸收过程中表现了极高的敏感性,当土壤含水量降低时，土壤养分供应参数对玉米幼苗磷吸收的敏感性与限制作用均增大。

This paper deals with the parameter sensitivity in the process of P uptake by seedlings of maize and soybean using the mechanistic nutrient uptake model proposed by Claassen. The studies show that : (a) the most sensitive parameters in this process are root elongation ratio and root radius: (b) under the same soil P level, the ability of root system of selected maize seedlings to absorb soil P is much Poorer than that of selected soybean seedlings, and this is due to the differences between the two plants in the two sensitive parameters of the maximum nutrient influx to root (Imax) and the root elongation ratio(K); (c) the soil water content in the process of P uptake by the two plants shows a very high sensitivity, and the soil parameters' sensitivity and limit to P uptake by maize seedlings increase when soil water content decrease.