土壤是森林生态系统的主要组成部分，对气候变化的响应可能潜在的影响森林生态系统的物质循环过程。土地利用变化深刻影响着土壤生态系统物理化学特征。再造林是青藏高原东缘亚高山区域一个重要林业实践活动。因此，再造林活动不仅影响土壤物理化学特性，而且可能进一步影响森林土壤对未来气候变化响应的方式和程度。
中国科学院成都生物研究所生态研究中心刘庆研究员课题组徐振锋等人通过开顶式生长室模拟增温的研究方法，比较研究了人工针叶林和天然针叶林土壤N转化及有效性，土壤微生物特性和酶活性对一定量气候变量的初期响应。
研究表明：在生长季节内，模拟增温往往能显著增加天然林土壤的可溶性碳、氮库，而对人工林土壤的可溶性碳、氮库没有影响。短期模拟增温显著增加两类森林生态系统土壤净N矿化和有效性，但增加方式不同(人工林氨化作用占主导而天然林硝化作用占主导)。增温初期，两类生态系统的土壤微生物生物量碳、氮都没有明显变化。与土壤氮转化相关的组分库对模拟增温的响应与生态系统类型和季节变化密切相关，天然林对模拟气候变化的响应更为敏感。增温导致的土壤有效氮库的增加可能在一定程度上提高森林生产力，但增温引发的天然林可溶性土壤N库增加(可溶性有机氮和硝态氮)也可能通过淋溶方式从系统中大量丢失。（生物谷Bioon.com）
生物谷推荐英文摘要：
Applied Soil Ecology doi:10.1016/j.apsoil.2010.07.005
Initial soil responses to experimental warming in two contrasting forest ecosystems, Eastern Tibetan Plateau, China: Nutrient availabilities, microbial properties and enzyme activities
Zhen-feng Xua, b, Rong Hua, Pei Xionga, Chuan Wana, Gang Caoa and Qing Liu
a Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
b Graduate University of the Chinese Academy of Sciences, Beijing 100039, China
In order to understand the effects of projected global warming on soils in different land-use types, we compared the impacts of warming on soils in two contrasting forest ecosystems (a dragon spruce plantation and a natural forest) using the open-top chamber (OTC) method in the Eastern Tibetan Plateau of China. The OTC on average enhanced daily mean soil temperatures by 0.61 °C (plantation) and by 0.55 °C (natural forest) throughout the growing season, respectively. Conversely, soil volumetric moisture declined by 4.10% in the plantation and by 2.55% in the natural forest, respectively. Warming did not affect dissolved organic C (DOC) and N (DON) in the plantation but significantly increased them in the natural forest. Elevated temperature significantly increased net N mineralization rates and extractable inorganic N pools in both sites. Warming had no effects on microbial biomass C (MBC) and N (MBN) and their ratios (MBC/MBN) in the plantation and significantly increased MBC and MBN only late in the growing season in the natural forest. Warming did not affect basal respiration in the plantation but significantly increased it in the natural forest. No clear change was observed in metabolic quotient between warming regimes for both forest types. Experimental warming tended to increase invertase and urease in both forest soils. Measured pools related to N turnover generally showed significant interactions in warming, forest type and sampling date. Taken together, our results indicate that responses of soils to experimental warming depend strongly on forest managements and seasons.
