养分(磷)吸收机理模型的应用研究Ⅰ.预测幼苗施磷的最佳混土比例

STUDIES ON THE APPLICATIONS OF MECHANISTIC NUTRIENT (P) UPTAKE MODELS . PREDICTING THE MOST EFFICIENT P PLACEMENT FOR SEEDLINGS

采用Ｃｌａａｓｅｎ的养分吸收机理模型探讨了一定条件下玉米与大豆吸收磷的最佳施磷混土比例。研究结果表明：供试Ａ土壤（壤质棕红壤）上大豆幼苗的施磷水平为１５、３０与６０μｇ／ｇ时的最佳施磷混土比例分别为２５％、７５％和１００％；同样供试Ａ土壤上，玉米幼苗在上述３个施磷水平下的最佳施磷混土比例依次为２５％、５０％及７５％，而在较粘重的Ｂ土壤（粘质棕红壤）上，其值相应为６．２％、１２．５％、和２５．０％。因此，玉米与大豆幼苗的最佳施磷混土比例均随施磷水平的提高而增大，而且当土壤的吸附固磷能力较强时，幼苗的最佳施磷混土比例则较低。

This paper dealt with the most efficient P placement in the process of P uptaken by seedlings of maize and soybean using the mechanistic nutrient uptake model proposed by Claassen. The studies showed that: When the P ratio applied to soybean seedlings on A soil is 15, 30 and 60 g/g, the most efficient P placement is 25%, 75% and 100% respectively. At the same P ratio, the most efficient P placement is 25%, 50% and 75% respectively for maize seedlings on the same soil, but it is 6.2%, 12.5% and 25.0% respectively for maize seedlings on B soil with more clay. Therefore, the most efficient P placement for both maize and soybean seedlings increases with the increase of the P ratio applied, and the most efficient P placement will be lower when the ability of soil to absorb and fix P is stronger. These study results can be applied to related agriculture practices. Furthermore, this paper also discussed the key measures to predict exactly the most efficient P placement based on some approaces of related studies.