Gross nitrification rates in four Japanese forest soils: heterotrophic versus autotrophic and the regulation factors for the nitrification
Gross nitrification rates in four Japanese forest soils: heterotrophic versus autotrophic and the regulation factors for the nitrification
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DOI：
10.1007/s10310-011-0287-0
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发表时间：
2011-10-01
影响因子：
1.5
通讯作者：
Shibata, Hideaki
中科院分区：
文献类型：
--
作者：
Kuroiwa, Megumi;Koba, Keisuke;Shibata, Hideaki
用N-15池稀释法测定了森林土壤中总NH 4（+）和NO3（-）的产生量。从日本北方到南方的四个森林中收集了具有自然气候梯度的矿物表土（0-10 cm深），以阐明森林土壤中总硝化速率的调节机制。此外，我们试图使用乙炔作为自养硝化的特异性抑制剂来评估异养硝化在总硝化中的相对重要性。NH 4（+）的总产生速率（3.1-11.4 mg N kg（-1）day（-1））和总硝化速率（0.0-6.1 mg N kg（-1）day（-1））在不同地点之间存在显著差异。总异养硝化率在这项研究中是低的，表明异养硝化作用是次要的，在日本的大多数森林矿物表土。总自养硝化作用与总NH（4）（+）产生量、土壤N和土壤C浓度之间存在显著相关性，而与土壤pH之间不存在相关性。以及总自养硝化作用停止的临界土壤C/N比。结果表明，当NH 4（+）的有效性较低时，NH 4（+）的产生和消耗的紧密耦合会阻止自养硝化菌利用NH 4（+）。
Measurements of gross NH (4) (+) and NO (3) (-) production in forest soils were conducted using the N-15 pool dilution method. Mineral topsoils (0-10 cm depth) were collected from four forests from northern to southern Japan with a natural climate gradient to elucidate the mechanisms regulating gross nitrification rates in forest soils. Additionally, we attempted to evaluate the relative importance of heterotrophic nitrification in gross total nitrification using acetylene as a specific inhibitor of autotrophic nitrification. Distinct differences were found among sites in the gross rates of NH (4) (+) production (3.1-11.4 mg N kg(-1) day(-1)) and gross total nitrification (0.0-6.1 mg N kg(-1) day(-1)). The rates of gross heterotrophic nitrification were low in this study, indicating that heterotrophic nitrification is of minor importance in most forest mineral topsoils in Japan. Significant relations were found between gross autotrophic nitrification and gross NH (4) (+) production, soil N, and soil C concentrations, but none was found between gross autotrophic nitrification and soil pH. We determined the critical value of the gross NH (4) (+) production rates for gross autotrophic nitrification under which no gross autotrophic nitrification occurred, as well as the critical soil C/N ratio above which gross autotrophic nitrification ceased. Results show that tight coupling of production and consumption of NH (4) (+) prevents autotrophic nitrifiers from utilizing NH (4) (+) as long as NH (4) (+) availability is low.