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选用陕西省六种主要耕作土壤及其剖面不同层次２３个土样，在实验室培养条件下，研究其硝化作用的特点，并选用ｄＮ／ｄｔ=ｂＮ（Ｂ－Ｎ）／Ｂ方程（式中，Ｎ为硝态氮的累积量，ｔ为试验培养时间，Ｂ为硝态氮累积量的渐进值），描述硝化作用过程中硝态氮含量随时间的用积，获得定量描述硝化作用强弱的两个指标（Ｋｍｘ和ｔｄ）。结果表明耕层土壤由北向南硝化作用强度逐渐减弱，硝化作用的最大速率（Ｋｍｘ）变幅为 ２．７０～１６．５８ｍｇ／ ｋｇ．ｄ，陕北的黑垆土硝化作用进行最快，陕南的黄泥巴最慢。在不同土壤剖面中，硝化作用由上到下呈现减弱趋势，硝化作用的最大速率（Ｋｍｘ）随上层深度增加而下降，迟缓期（ｔｄ）随土层深度增加而延长，在粘化层和粘重土层中、硝化作用非常微弱或基本不发生硝化作用。这些不同土壤及剖面层次硝化作用的差异与土壤的物理、化学特性有关。
Sixteen main cultivated soils in Shaanxi Province and 23 soil samples from different layers were selected to study the characteristics of nitrification under laboratory culture conditions. The equation of dN / dt = bN (B-N) / B , N is the cumulative amount of nitrate nitrogen, t is the experimental culture time, B is the gradual value of the cumulative amount of nitrate nitrogen), describe the nitric nitrogen content with time during the nitrification process to obtain a quantitative description of the strength of nitrification The two indicators (Kmx and td). The results showed that the intensity of nitrification decreased from north to south and the maximum rate of Kmx varied from 2.70 to 16.58 mg / kg. d, the nitrification of black loess soil in northern Shaanxi was the fastest, and the yellow mud of southern Shaanxi was the slowest. In different soil profiles, the nitrification showed a decreasing trend from top to bottom. The maximum rate of nitrification (Kmx) decreased with the increase of the depth of the upper layer, while the delayed period (td) increased with the depth of the soil. Heavy soil, nitrification is very weak or no nitrification occurs. The differences in nitrification at these different soils and sections are related to the physical and chemical characteristics of the soil.