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以腾格里沙漠东南缘天然植被区藓类结皮和无结皮土壤为对象,采用野外原状土柱封顶埋管法对无机氮库和净氮转化速率的季节动态特征进行研究.结果表明:藓类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变化特征,不同月份间差异显著.在非生长季,3和10月土壤有效氮含量和净氮转化速率显著高于其他月,氮矿化过程以固持态为主,两样地间土壤净氮转化速率无显著差异;在生长季,土壤有效氮含量和净氮转化速率显著增加,6—8月时达到峰值,分别为17.18 mg·kg-1和0.11 mg·kg-1·d-1.两样地土壤净硝化速率和净氮矿化速率在各月间差异显著,均表现为藓类结皮土壤>无结皮土壤.土壤铵态氮和硝态氮含量4和5月时表现为藓类结皮土壤(2.66和3.16 mg·kg-1)>无结皮土壤(1.02和2.37mg·kg-1);6—9月则表现为无结皮土壤(7.01和7.40 mg·kg-1)>藓类结皮土壤(6.39和6.36mg·kg-1).藓类结皮的繁衍与拓殖能够调节土壤有效氮含量、促进土壤氮矿化过程,是影响土壤氮素循环的重要生物因素.
Based on the moss crusts and non-crust soil in the natural vegetation area on the southeastern margin of the Tengger Desert, the season dynamic characteristics of inorganic nitrogen pools and net nitrogen transformation rate were studied using the open pit soil tube method in situ. The results showed that: There was a significant seasonal variation in available nitrogen and net nitrogen conversion rates in moss crusts and non-crusts, with significant differences between months. In the non-growing season, soil available nitrogen and net nitrogen conversion rates were significantly higher in March and October In the other months, the nitrogen mineralization was mainly in the solid state, and there was no significant difference in net N conversion rate between the two plots. During the growing season, the available nitrogen and net nitrogen conversions increased significantly, reaching the peak from June to August, Respectively, 17.18 mg · kg-1 and 0.11 mg · kg-1 · d-1, respectively.The soil net nitrification rate and net nitrogen mineralization rate of the two plots were significantly different in each month, showing moss crust soil> no knot The contents of soil ammonium nitrogen and nitrate nitrogen in April and May were moss crust (2.66 and 3.16 mg · kg -1)> non-crust soil (1.02 and 2.37 mg · kg -1), respectively. From June to September, the soil showed mossy crust (7.01 and 7.40 mg · kg-1)> moss-crust soil (6.39 and 6.36 mg · kg-1), respectively. The crust can be adjusted to colonize and multiply available nitrogen in the soil, promote soil nitrogen mineralization process, it is an important factor affecting the biological soil nitrogen cycle.