Seasonal changes and controlling factors of gross N transformation in an evergreen plantation forest in central Japan
Seasonal changes and controlling factors of gross N transformation in an evergreen plantation forest in central Japan
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DOI：
10.1007/s10310-013-0391-4
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发表时间：
2014-02
影响因子：
1.5
通讯作者：
N. Tokuchi;S. Yoneda;N. Ohte;Nobuaki Usui;K. Koba;Megumi Kuroiwa;H. Toda;Y. Suwa
中科院分区：
文献类型：
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作者：
N. Tokuchi;S. Yoneda;N. Ohte;Nobuaki Usui;K. Koba;Megumi Kuroiwa;H. Toda;Y. Suwa
我们进行了一个全年的总氮转化率的测量，使用15 N稀释法，并分析了季节变化和调节总氮转化的机制在日本中部的吉柳实验林。有机层土壤微生物生物量C（SMB-C）从休眠期到生长期呈下降趋势，而SMB-N的变化趋势不明显。这导致SMB-C/N在休眠期高，在生长期低，表明微生物组成的季节性变化。没有明显的季节性趋势，发现总NH 4+生产率在O或表面矿质土壤层。与此相反，NH 4+消耗率随季节变化，高值在1月和4月在休眠季节和低值在7月和10月在生长季节。NH 4+净生产率的季节性波动没有明显的趋势。总NH 4+产生和总NH 4+消耗速率是总硝化速率的10倍。几乎所有产生的NH 4+都被固定化，这表明在该研究地点，N紧密循环。结合总氮转化率的结果，高SMB-C/N微生物的优势可能会刺激休眠季节的固定化。在这个研究地点，微生物组成的变化可能会影响总氮转化通过固定效率。
We conducted a year-round measurement of gross N transformation rates using the15N dilution method, and analyzed seasonal changes and the mechanisms regulating gross N transformation in the Kiryu Experimental Forest in central Japan. While soil microbial biomass C (SMB-C) decreased from the dormant to growing seasons at the organic (O) horizon, no significant trend was observed in SMB-N. This resulted in SMB-C/N being high in the dormant season and low in the growing season, and suggests that the microbial composition changed seasonally. No clear seasonal trend was found in gross NH4+production rates at either the O or surface mineral soil horizons. In contrast, the NH4+consumption rate varied seasonally, with high values in January and April during the dormant season and low values in July and October during the growing season. There was no clear trend in seasonal fluctuation of net NH4+production rates. Gross NH4+production and gross NH4+consumption rates were 10 times greater than the gross nitrification rate. Almost all of the produced NH4+was immobilized, indicating that N tightly cycles at this study site. Considered together with results of the gross N transformation rates, the dominance of high SMB-C/N microbes might stimulate immobilization in the dormant season. At this study site, the change in microbial composition likely influences gross N transformation through immobilization efficiency.