[Gradient distribution of soil nitrogen and its response to climate change along the Northeast China Transect].
[Gradient distribution of soil nitrogen and its response to climate change along the Northeast China Transect].
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发表时间：
2005-02
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通讯作者：
Shuping Wang;Guangsheng Zhou;Suhua Gao;Jianping Guo
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作者：
Shuping Wang;Guangsheng Zhou;Suhua Gao;Jianping Guo
陆地样带是全球变化研究的重要而有效的方法。中国东北样带（NECT）位于中纬度43 ° 30 'N的沿着，东经112 ° ~ 130 ° 30' N，北纬42 ° ~ 46 °，是国际地球物理年（IGBP）确定的15条全球样带之一。它长约1600公里，宽约300公里。NECT以降水为主要驱动力，成为中国全球变化研究的有效平台。基于2001年野外调查和模拟试验，分析了样带土壤氮素的梯度分布及其对沿着气候变化的响应。结果表明，NECT土壤全氮和碱解氮与经度呈极显著相关，相关系数分别为0.695（P < 0.001）和0.001。636（P < 0.001），与土壤有机碳水平分布相似。土壤速效氮含量由东向西逐渐降低，可能是限制植物生长的因素之一。沿着不同生态系统土壤全氮和碱解氮从表层到下层的下降速率不同。土壤全氮和速效氮含量与土壤pH、全碳和活性碳、全磷和有效磷、全硫、全锌和有效锌、有效钾、有效锰、容重、持水力和总孔隙度呈线性关系。与降水量呈显著线性相关，相关系数分别为0.682（P < 0.001）和0.688（P < 0.001）。短期模拟试验表明，CO2浓度倍增和土壤水分状况对土壤全氮和速效氮的影响不显著，变异系数分别为5.55%和3.84%。
Terrestrial transect is an important and effective method for global change study. The Northeast China Transect (NECT), which is assigned along the latitude 43 degrees 30'N in the mid-latitude of temperate zone and located at 112 degrees-130 degrees 30'E and 42-46 degrees N, is one of the fifteen global transects recognized by IGBP. It is about 1600 km in length and 300 km in width. The NECT is mainly driven by precipitation, and becomes an effective platform of global change study in China. Based on the field survey in 2001 and a simulated experiment, this paper analyzed the gradient distribution of soil nitrogen and its response to climate change along the Transect. The results indicated that soil total and available nitrogen in NECT were significantly related to longitude, with a correlation coefficient being 0.695 (P < 0.001) and 0. 636 (P < 0.001), respectively, and had a similar horizontal distribution with soil organic carbon. Soil available nitrogen content in the NECT was decreased from east to west, and could be one of factors restricting plant growth. The decreasing rate of soil total and available nitrogen from topsoil to subsoil was different with ecosystems along the NECT. Soil total and available nitrogen contents had a close linear relationship with soil pH, total and labile carbon, total and available phosphorus, total sulphur, total and available zinc, available potassium, available manganese, bulk density, water holding capacity, and total porosity. They also had a significant linear relationship with precipitation, the correlation coefficient being 0.682 (P < 0.001) and 0.688 (P < 0.001), respectively. The short-term simulated experiment showed that doubled ambient CO2 concentration and soil moisture regime had no significant effects on soil total and available nitrogen, the variation coefficients being 5.55% and 3.84%, respectively.