【摘要】 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。更多还原

【Abstract】 The 23 soil samples including the 6 types of managed soils were collected from different regions in Shanxi Province for this research project. The change of nitrate nitrogen accumulation with time was determined during the process of nitrification. The equation, dN/dt = bN(B-N) / B(N is the amount of NO3-N accumulation, t is time of incubation, and B is the asymptotic value of NO3-N, depending on the amount of NH4-N added to the soil), was used to represent the accumulation of nitrate nitrogen with time.The maximal rate of nitrification (Kmx) and the delayed period (td) were derived from the equation and used to charaterize quantitatively the nitrification process in various soil samples.The Kmx and td of surface soil samples were from 2.7 to 16.58 mg / kg. d and from l.3~3.5d, respectively. The Kmx decreased and td increased with soil depth. Some soil properties affected the rate parameters.更多还原