冻融对湿地土壤可溶性碳、氮和氮矿化的影响  

Effects of Freezing and Thawing on Dissolved Organic Carbon and Nitrogen Pool and Nitrogen Mineralization in Typical Wetland Soils From Sanjiang Plain,Heilongjiang,China

作　　者：周旺明[1] 王金达[1] 刘景双[1] 秦胜金[1] 王洋[1] 

机构地区：[1]中国科学院东北地理与农业生态研究所

出　　处：《生态与农村环境学报》2008年第3期1-6,共6页Journal of Ecology and Rural Environment

基　　金：中国科学院知识创新工程重要方向(KZCX2-YW-309);国家自然科学基金(90211003)

摘　　要：通过室内模拟试验,研究了不同冻融循环过程(-5—5℃或-25—5℃)对沼泽湿地土壤可溶性有机碳(DOC)、可溶性有机氮(DON)以及土壤有机氮矿化过程的影响。结果表明,随着冻融次数的增加,土壤DOC和DON含量呈先增加后降低趋势,土壤DOC含量在冻融1次(-5—5℃或-25—5℃冻融循环处理)后达最大值,而土壤DON分别在冻融2次(-5—5℃冻融循环处理)和4次(-25—5℃冻融循环处理)后达最大值。这说明在短期内冻融交替对土壤DOC和DON含量的影响较明显。冻结温度和冻融次数显著影响土壤有机氮矿化过程,且-25—5℃冻融循环比-5—5℃冻融循环矿化累积量高。冻融循环促进了土壤有机氮的矿化,有利于土壤有效氮的累积,为春季植物生长提供足够的氮素,对维持湿地生态系统稳定具有重要意义。Contents of dissolved organic carbon and nitrogen （DOC and DON） and nitrogen mineralization of wetland soils different in freezing and thawing cycle were investigated through an indoor incubation experiment. Results show that with the number of the cycles increasing, DOC and DON rose up first and then declined. DOC peaked after one cycle, either - 5 to 5℃ or - 25 to 5℃, while DON did after two cycles of - 5 to 5℃ and four cycles of - 25 to 5℃, which indicates that the effect of freezing and thawing alternation within a short time period was significant on DOC and DON in the soil. It was also quite obvious that nitrogen mineralization in the wetland soil was affected by freezing temperature and number of freezing and thawing cycles, and the soils under cycles of - 25 to 5℃ were higher than under cycles of - 5 to 5℃ in accumulative nitrogen mineralization. Alternation of freezing and thawing accelerated soil nitrogen mineralization, which facilitated accumulation of soil available nitrogen, thus building up an adequate N pool to meet the demand for N of the plant growing in the spring, which contributes significantly to maintenance of stability of the wetland ecosystem.

关 键 词：冻融过程 可溶性碳 可溶性氮 氮矿化 沼泽湿地 三江平原 

分 类 号：X144[环境科学与工程—环境科学]