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生物土壤结皮对荒漠生态系统的维持与改良发挥着重要作用。土壤微生物可敏感地指示土壤质量,是衡量荒漠区生态健康程度的重要生物学特征,而对荒漠区生物土壤结皮与土壤微生物关系知之甚少。本研究设计了两组对比试验。一组以腾格里沙漠东南缘的1956、1964、1981、1991年的植被固沙区结皮下的沙丘土壤为对象,以流沙区和天然植被区为对照。另一组以植被固沙区人为干扰生物土壤结皮下的沙丘土壤为研究对象,以未干扰结皮下的沙丘土壤为对照。结果表明:腾格里沙漠东南缘植被固沙区的藻-地衣和藓类结皮均可显著提高土壤可培养微生物的数量和基础呼吸(P<0.05);适度人为干扰生物土壤结皮不会显著影响土壤可培养微生物的数量和基础呼吸,而严重人为干扰结皮可显著降低土壤可培养微生物的数量和基础呼吸,指示严重人为干扰结皮可导致荒漠区土壤质量下降;土壤可培养微生物的数量和基础呼吸也因结皮演替阶段的不同而有所不同,演替晚期的藓类结皮下土壤微生物数量和基础呼吸显著高于演替早期的藻-地衣结皮(P<0.05);土壤可培养微生物的数量和土壤基础呼吸与固沙年限均存在显著的正相关关系,随着沙丘固沙年限的增加,结皮层增厚,结皮下土壤微生物数量及基础呼吸显著增加(P<0.05);生物土壤结皮下土壤可培养微生物数量和基础呼吸呈现显著的季节变化,表现为夏季>秋季和春季>冬季。因此,腾格里沙漠东南缘植被固沙区的生物土壤结皮提高了土壤微生物数量和活性,表明生物土壤结皮有利于荒漠区土壤及荒漠生态系统的恢复。
Biological soil crusts play an important role in the maintenance and improvement of desert ecosystems. Soil microorganisms can sensitively indicate soil quality, which is an important biological feature to measure the ecological health in the desert area. However, little is known about the relationship between biological soil crusts and soil microbes in the desert area. This study designed two groups of comparative tests. A group of sand dunes under the crust of 1956, 1964, 1981, 1991 in the southeastern margin of the Tengger Desert was selected as the object and the runoff and natural vegetation areas were compared. In the other group, the soil of sand dune under the interference of biological soil crusts in the sand-fixing area of vegetation was taken as the research object, and the soil in the sand dunes without disturbing the crusts was taken as the control. The results showed that both algae-lichen and moss crusts in the southeastern margin of the Tengger Desert could significantly increase the number of soil-culturable microorganisms and the basal respiration (P <0.05), and no significant anthropogenic interference with soil crust Affecting the amount of soil-culturable microorganisms and the basal respiration, whereas severe anthropogenic disturbance of crusts could significantly reduce the amount of soil-culturable microorganisms and the basal respiration, indicating that severe anthropogenic disturbance of crusts could lead to the decline of soil quality in the desert; the amount of soil-culturable microorganisms And basal respiration were also different due to the stages of succession of soil crusts. The number of soil microbes and the basic respiration of moss crusts at the successional stage were significantly higher than those of early successional algal-lichen crusts (P <0.05) There was a significant positive correlation between the numbers of culturable microorganisms and the soil respiration and the years of sand fixation. With the increase of sand fixation years, the thickening of crusts, the number of soil microbes and the basic respiration of crusts increased significantly (P <0.05) Soil crusts under soil crusts can be cultured microorganisms and the basic respiration showed significant seasonal changes, the performance of summer> autumn and spring> winter. Therefore, the biological soil crusts in the vegetation sands-fixing area on the southeastern margin of the Tengger Desert increase the amount and activity of soil microbes, indicating that biological soil crusts are favorable for the recovery of desert soil and desert ecosystems.