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土壤供氮能力多以土壤速效氮多寡为指标,也有用硝化力培养法测定的氮素来表示。近年来国内外用 A 值法研究土壤供氮能力的研究报导虽已不少,但区内尚未见到这方面的报导。1952年 M.Fried 和 Dean 在研究土壤供磷能力时首先提出 A 值法。A 值法是假定土壤中存在着养分的两个来源,一种来源是土壤原有的养分,另一种来源是施用的肥料。作物从不同来源吸收的养分量与各自的有效养分总量成正比。即:土壤来源提供的有效养分总量/肥料来源提供的养分总量=该种养分从土壤中的吸收量/该种养分从肥料中的吸收量。1964年 Hunter 和 Carter 将土壤
Soil nitrogen availability and more soil available nitrogen index as an indicator, but also useful nitrification culture method to determine the nitrogen to represent. In recent years, there are a lot of reports about the research on soil nitrogen supplying ability by A value method both at home and abroad, but there is no report in this area yet. In 1952, M. Fried and Dean first proposed the A-value method when studying soil phosphorus supply. The A-value method assumes two sources of nutrients in the soil, one source being the soil’s original nutrients and the other source being the applied fertilizer. The amount of nutrients that crops absorb from different sources is directly proportional to their total available nutrients. Namely: total available nutrients supplied by soil source / total nutrients provided by fertilizer source = absorption of this nutrient from the soil / absorption of this nutrient from the fertilizer. 1964 Hunter and Carter will soil