【摘要】 以黄土高原南部典型旱耕地—休闲地土壤为对象 ,研究了中等水分条件下 (6 5 %的田间持水量 )土壤 N2 O排放的动力学特征 ,以及土壤深度和氮磷营养因子对 N2 O排放量的影响。结果表明 ,施肥和未施肥处理 ,土壤 N2 O排放累积量随时间 t的变化均符合修正的 Elovich方程 y=bln(t) +a。反应初始浓度 (a)和表观反应速率(dy/ dt)大多数随土壤深度增加而递增 ,但 15℃时以 10 cm深处反应初始浓度最大 ;2 5℃时 ,表观反应速率以 15cm深处最高 ,即在中等水分条件下 ,随温度升高 ,试验土壤 10～ 15 cm深处为 N2 O产生的活跃场所。磷素对土壤N2 O的减排效应不仅表现在排放总量上 ,也存在于动力学参数初始浓度和表观反应速率之中。更多还原

【Abstract】 Kinetic characteristics of soil N 2O emission with the mediate moisture (65% of the field capacity) and the concerned factors (N,P and the different soil depths) were studied in the fallow field of Orthic Anthrosoils in the south of Loess Plateau.Results showed that the accumulated curves of N 2O emission with the incubation time could be described by the revised Elovich equation of y=b ln( t)+a in both the fertilized treatment and the checks.The initial reactive concentration ( a ) and the apparent reactive rate (d y /d t ) largely increased with the increase of soil depths.The initial reactive concentration ( a ) in the depth of 10 cm at 15 ℃ and the apparent reactive rate (d y /d t ) in the depth of 15 cm at 25 ℃ reaches the highest.N 2O occurred mainly in the depth of 10~15 cm of the test soil with the increase of incubation temperature under the mediate soil moisture.The reduction effects of P fertilizer on the N 2O emission were showed in the total amount of N 2O emission and were reflected through the initial reactive concentration ( a ) and the apparent reactive rate (d y /d t ).更多还原