甘南尕海湿地泥炭地不同退化状态下氮素的特征

目的]分析甘南尕海湿地泥炭地不同退化状态下土壤氮素的变化特征,为尕海泥炭地的生态恢复建设以及保护和利用提供科学依据。方法]采用野外采样与室内分析相结合的方法,研究泥炭地退化过程中表层(0—40cm)土壤氮素的变化特征。结果]除未退化土壤外,其他3种退化类型的土壤全氮含量均为9月显著高于7月,而土壤C/N比与土壤全氮变化恰好相反;土壤各相应层铵态氮含量7和9月基本呈相同的变化趋势;0—20cm层土壤速效氮9月显著高于7月,20—40cm层(除中度退化)恰好相反。从剖面分部上看,土壤全氮在20—40cm层富集;土壤C/N比和速效氮含量基本在20—40cm层富集;除中度退化外,土壤铵态氮在0—20cm层富集。结论]4种退化阶段的泥炭地土壤全氮含量具有明显的时间变化,说明植被对尕海泥炭地的恢复具有十分重要的作用。

Nitrogen Characteristics of Peatland Under Different Degradation States in Gahai Lake Wetland of South Gansu Province

Objective] The objective of the study is to analyze the variation of peat soil nitrogen under different degradation states in Gahai lake in South Gansu Province and provide scientific basis for peatland ecological restoration and protection in Gahai lake.Methods] Through field sampling and laboratory analysis, we studied the changes in surface soil nitrogen(0-40 cm) of peat land with degradation.Results] Except for the undegraded peat land, the total nitrogen content of the other 3 types of degraded peat land was significantly higher in September than that in July, while the soil C/N ratio and soil total nitrogen change in an opposite direction. The change in the content of ammonium nitrogen in soil was the same in July and September. The soil available nitrogen in the 0-20 cm layer was significantly higher in September than that in July, and the 20-40 cm layer(except for moderate degradation) was the opposite. In the whole profile, total soil nitrogen, soil C/N ratio and available nitrogen content were enriched in 20-40 cm layer. Except for moderate degradation, soil ammonium nitrogen was enriched in the 0-20 cm layer.Conclusion] The total nitrogen content of 4 kinds of degraded soil has obvious temporal variation, indicating that the vegetation plays an important role in the recovery of peatland in Gahai lake.