论文部分内容阅读
以腾格里沙漠东南缘沙坡头天然植被区藻地衣混生结皮和无结皮土壤为对象,采用野外原状土柱封顶埋管法,研究土壤硝态氮、无机氮、净硝化速率和净氮矿化速率的季节动态特征。结果表明:藻地衣混生结皮和无结皮土壤有效氮含量和净氮转化速率存在明显的季节动态,表现为生长季高峰期>生长季初期,夏季7月和8月土壤有效氮和净氮转化速率最大;两个样地土壤在生长季不同时期有效氮和净氮转化速率也存在差异。生长季初期,藻地衣混生结皮和无结皮土壤硝态氮和无机氮含量无显著差异,且温度是影响土壤氮素转化的关键环境因子。生长季高峰期,两个样地土壤有效氮含量和净硝化速率均表现为无结皮>藻地衣混生结皮,且水分和温度分别是影响土壤氮硝化和矿化过程的关键环境因子。由此可见,藻地衣结皮的繁衍在一定程度上抑制了土壤氮的硝化过程,因而可以减少养分的散失,是养分贮存的重要机制。
The algal lichen-mixed crusts and non-crust soil in the natural vegetation area of Shapotou area in the southeast edge of the Tengger Desert were used as the object to study the soil nitrate nitrogen, inorganic nitrogen, net nitrification rate and net Seasonal dynamics of nitrogen mineralization rate. The results showed that there were obvious seasonal dynamics of algal lichen mixed-acid and non-mesoderm soil available nitrogen and net nitrogen conversion rate, which were the peak of growing season> the beginning of growing season, the contents of soil available nitrogen and net nitrogen in July and August in summer, The conversion rate was the highest. There were also differences in the conversion rate of available nitrogen and net nitrogen between the two plots in different periods during the growing season. In the early growing season, there was no significant difference in the contents of nitrate nitrogen and inorganic nitrogen in algal lichen mixed crusts and non-crusts, and temperature was the key environmental factor that affected soil nitrogen transformation. During the peak season, both soil available nitrogen and net nitrification rates showed no skin> algal lichen mixed crust, and water and temperature were the key environmental factors affecting soil nitrogen nitrification and mineralization, respectively. Thus, the proliferation of algae lichen crust to a certain extent inhibited the nitrification of soil nitrogen, which can reduce the loss of nutrients is an important mechanism for nutrient storage.