水稻含氮率与叶色,每亩鲜重与长势均呈显著正相关。因此,测定水稻含氮率及每亩鲜重,两者的乘积为每亩吸氮量,是进行水稻科学施肥诊断的必要步骤。用凯氏法测定含氮率,时间比较长,达不到快速的目的;用每科禾苗平均重量乘每亩苗数作为每亩鲜重的估量很不准确,往往差异很大。 Nitrogen content of rice and leaf color, fresh weight per acre and growth were significantly positive correlation. Therefore, the determination of nitrogen content in rice and fresh weight per acre, the product of N absorption per acre, is a necessary step for the scientific diagnosis of rice fertilization. Kjeldahl method for the determination of nitrogen content, a long time, not up to rapid purpose; the average weight of seedlings per plant multiplied by the number of acres per acre seedlings per acre fresh weight estimation is very inaccurate, often very different.