不同土地利用方式对三江平原湿地土壤酶分布特征及相关肥力因子的影响

以中国科学院三江平原湿地生态试验站为对象,研究了不同利用方式(湿地草甸、旱田系统、退耕成草、退耕成林)对土壤酶分布特征及相关肥力因子的影响.结果表明:土壤利用方式不同,土壤酶活性(转化酶、脲酶、磷酸酶和过氧化氢酶)、有机碳含量和土壤养分含量有较大差异.未开垦的湿地草甸,土壤酶活性、有机碳和土壤养分含量均为最高,开垦20年后,上述各种指标含量均有较大幅度降低;由耕地恢复为湿地后,土壤酶活性、有机碳和土壤养分含量有较大幅度的回升,而耕地恢复为林地后,上述各种成分也有不同程度地增加.因此,要保持三江平原湿地较高的土壤肥力和生物学特性,维持三江平原湿地土壤有机碳库稳定,对已开垦湿地进行部分退耕还湿势在必行.

Characteristics of Soil Enzyme Activity and Fertility under Different Types of Land Use in Wetland of Sanjiang Plain

Based on the wetland in the Sanjiang Ecology Station of Chinese Academy of Sciences,the characteristics of soil enzyme activity and fertility under different types of land use,including wetland ecosystem,dryland ecosystem,conversion from dryland to wetland,conversion from dryland to forestland,were investigated.The results showed that there was great significance between the soil enzyme activity(invertase,urease,phosphatase,and catalase),the contents of organic carbon and soil nutrients under different types of land use,they were the highest in the unreclaimed wetland,20 years after the wetland was reclaimed,the enzyme activity,the contents of organic carbon and soil nutrients all declined greatly than that in wetland,when the reclaimed dryland was recovered to wetland,the enzyme activity,the contents of organic carbon and soil nutrients increased significantly than that in dryland,however,when the reclaimed dryland was recovered to forestland,the contents of all above components were also increased at a different extent than that in dryland.Therefore,it is imperative under the situation to recover the wetland from dryland so as to keep high soil fertility and biological activity,and to maintain the stability of organic carbon in the wetland of Sanjiang plain.