农作物对氮肥吸收速率的研究现状

The Present Status of Study on Uptake of Nitrogen by Crop Roots

农作物对氮素吸收量的确定是衡量农田氮肥利用率、拟定最优施肥措施的重要依据，也是农田氮素转化运移模拟模型中的重要参数。就国内外有关农作物对氮素吸收量的几种主要计算方法，即根据根系吸水率和土壤溶液含Ｎ浓度估算根系吸氮量的方法、根据作物根系的吸氮能力而估算根系吸氮速率法和根据作物潜在氮素需求函数确定根系吸氮量的方法进行了总结评述。

Crop nitrogen uptake is the basic data for the evaluation of the field utilization efficiency of nitrogen fertilizer and the selection of best fertilizer management practices,and also the important input to the mathematical models for the simulation of nitrogen transformation and transport in the field.In this paper,the methods for the estimation of crop nitrogen uptake are summarized on the basis of literature review.The nitrogen uptake equations are classified into three categories:a)eqations based on crop water uptake and nitrogen concentration in the soil;b) equations estabished on the crop root nitrogen abstraction capacity;and c) eqations developed on the basis of the potential nitrogen demand by crops at different growth stages.In addition,the conditions for application of different uptake equations are also discussed.