【摘要】 <正> 测算某一作物在不同土壤肥力上的最佳氮肥施用量,最常见的计算公式为: Q_r=Q_D-Q_s/E_f 式中Q_r为氮素需要量;Q_D为最大经济产量时的需氮量;Q_s为作物生长期土壤可供给的有效氮量;E_f为肥料利用率。其中较难求得的参数为土壤供氮量Q_S,国内外已有不少学者对土壤供氮能力作了大量研究。作者工作指出:土壤氮素矿化量累积曲线与早更多还原

【Abstract】 This article lays stress on the discussion of exercising the maximum application rate of nitrogen, and forecasting the nitrogen responses of early rice plants.1. The maximum amount of nitrogen applied to the early rice plants was calculated based on the nitrogen mineralization capacity （Ye） of soil with the empirical equation X’_max=88.77-2.83Ye （r=0.6161）.The outgrowths of the estimation and the data of X’max obtained from field experiments were very close to an average c.v. of 15.42%, and only 13.58% for well-drained paddy soils.The empirical equation secured by the determination of alkali-hydrolized nitrogen by Conway’s method was X’max=88.47-1.138 N alk for well-drained paddy soil, which was quite close to that obtained in field experiments, with an average c.v. of 15.35%.2. By substituting the data obtained from soil nitrogen mineralization intensity （K-value） and capacity （Ye-value） into the empirical equation, it would be able to forecast the nitrogen responses of early rice plants. The algebraic formulae of calculating a, b, o values in the case of welldrained paddy soils are:a’=（1000K/1.868+1.118K） B’=[2(y’_max-a’)/X’_max]c’=(-b’/2X’_max) Y’（max）=（1000a’/178.7+0.985a’）3. Based on the above mentioned equations, trial was made to draw out a programme for model EL-5100 programme controlled computer, It was clearly shown that the curve depicted from the display of the computer was in good accord with that of field experiments.There is no doubt that the direct use of soil test with Conway’s method for estimating the maximum application rate of nitrogen and forecasting the yield of early rice plant is applicable.更多还原