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自1952年M.Friea和L.A.Dean提出A值概念以来,在土壤植物营养研究中现在已为广大学者所接受和普通采用。关于A值概念的评价及其具体应用,在国外报道较多,在国内近年来才开始关于A值概念应用的探索,报道甚少。本文就近年来我们在~N(15)示踪肥料试验中的部份资料加以整理,对土壤氮A值(A_N)进行初步探讨。 一、土壤A值的基本概念 土壤A值是土壤有效养分的一个定量指标,是指作物生长发育期间,在土壤中来源于土壤原有的某种有效养分的总量。A值概念是基于这样一个设想:假定在土壤中存在着养分的两种来源,一种来源是土壤原有的养分,另一种来源是所施用的一定数量的肥料,作物从其中每种来源吸收的养分量与各自的有效养分总量成正比,即:
Since the concept of A was proposed by M. Friend and L.A. Dean in 1952, they have now been accepted and accepted by most scholars in soil plant nutrition research. On the A value of the concept of evaluation and its specific application, more reports in foreign countries, in China in recent years began to explore the concept of value A exploration, reported very little. In this paper, some data in the ~ (15) tracer fertilizer experiment in recent years were sorted out to discuss the soil nitrogen A value (A_N). First, the basic concept of soil A value Soil A value is a quantitative index of soil available nutrients, refers to the crop growth and development, in the soil from the original soil some of the total amount of available nutrients. The A-value concept is based on the assumption that two sources of nutrients exist in the soil, one source being soil-derived nutrients and the other source being a given amount of fertilizer applied, from which each crop The amount of nutrients absorbed is proportional to the total effective nutrients, namely: