【作者】 宁远英；

【导师】 张功；

【作者基本信息】 内蒙古师范大学 ， 植物学， 2010， 硕士

【摘要】 本文通过对内蒙古科尔沁沙地奈曼旗中南部的流动沙丘、半固定沙丘和固定沙丘样地的植被及生物结皮类型进行了调查研究,发现半固定沙丘上形成了以蓝藻、绿藻为主要类群的藻结皮;而固定沙丘上除了存在藻结皮外,进而发育出以苔藓植物为主的藓结皮。形成固定沙丘藻结皮的优势种与半固定沙丘藻结皮的优势种基本相同,但其种类略有差异。通过对不同类型生物结皮及下层土壤的土壤微生物数量、土壤微生物量碳、氮、土壤酶活性、土壤因子的季节动态变化分析及各指标之间的相关性研究,表明:1.科尔沁沙地不同样地土壤中的微生物数量均为:细菌>自生固氮菌>放线菌>霉菌。不同深度土层的微生物数量略有差异:流动沙丘的表层下层土壤的微生物数最多,而半固定、固定沙丘的表层土壤的微生物数均最多,并随着土壤深度的增加而逐渐减少。土壤微生物总数因季节而异:夏季>秋季>春季>冬季,且同一样区各土层的四大类群土壤微生物数量的年季动态变化也不尽相同:细菌和自生固氮菌夏、秋两季最多,而放线菌和霉菌秋、夏两季最多,但四大类群土壤微生物冬季均最少。2.土壤微生物生物量碳(MBC)、土壤微生物生物量氮(MBN)与土壤微生物数量呈正相关,即:GX>GZ>GW>BZ>BW>L;不同深度土层的MBC、MBN含量略有差异,除流动沙丘样区外,其它样区的表层土壤中的MBC、MBN含量最高,并随着土壤深度的增加而急剧降低。流动沙丘没有明显的季节性差异,而其它样区的MBC、MBN都有显著甚至极显著的季节性差异,即秋季土壤的MBC、MBN含量最高,夏季、春季,冬季依次降低。3.不同类型样地中的三大类土壤水解酶(脲酶、蛋白酶和转化酶)具有显著差异(P<0.05),即:GX>GZ>BZ>GW>BW>L。除了流动沙丘,其它样区的土壤水解酶都随着土壤深度的增加而减少,且表层土壤中水解酶活性与3cm以下土层相比存在显著或极显著差异。同时,三大类土壤水解酶也存在季节差异。与水解酶不同,不同类型样地中的土壤多酚氧化酶活性为:GX>GZ>GW>BZ>BW>L;但多酚氧化酶活性与水解酶都随着土壤深度的增加而减少,且存在季节性差异。4.不同样地的土壤水分和pH值差异不显著。随着流动沙丘向半固定、固定沙丘发展,沙土中的粗砂粒含量逐渐降低,细砂含量逐渐升高;特别是当有生物结皮出现时,土壤中出现了粉砂。从剖面结构上分析,生物结皮对表层土壤中粒径的改善作用要远远大于其它土层。除全钾外,土壤有机碳、有机质、全氮、全磷等土壤养分均随着沙丘的固定,生物结皮的出现、发展而大量增加,即生物结皮的出现增加了土壤养分,改善了土壤肥力。各种土壤养分含量随季节变化差异显著。5.细菌、微生物总数和MBC、MBN具有显著的相关性,自生固氮菌、放线菌、霉菌与MBC、MBN则达到极显著水平,土壤微生物数量与土壤酶活性之间呈正相关,表层土壤有机质、有机碳、全氮以及全磷与土壤微生物、土壤酶以及土壤颗粒都具有不同程度的相关性。进而表明土壤微生物、土壤酶与土壤各因子之间是相互影响、互相依存的。更多还原

【Abstract】 This paper was conducted to study on the kinds of vegetation plots and biological soil crusts in moving dunes, semi-fixed dunes and fixed dune on southeastern Naiman in Horqin sand land, Inner Mongolia. It was found that there were algal crusts with blue-green algae and green algae, as the main taxa, in semi-fixed sand dune. Besides algal crust, there were moss crusts, most of which were bryophytes, in the fixed sand dune, However, the formation of the algal crust dominant species are almost the same in fixed sand dunes and semi-fixed sand dunes , but the species are slightly different. We have studied the seasonal dynamics of the different stages of biological soil crusts and soil microbe quantity、soil microbial biomass carbon, nitrogen, soil enzyme activities and soil factors of the lower layers, and the relativity among them. The results are:1.Microbe quantities in different kinds of plots in Horqin sand land all show that bacteria >azotobacter >actinomyceto> fungi. Microbe quantities of different soil layers are slightly different. The microbe quantities of the moving dunes are the most plentiful in the lower floor of top layer, and that the top layer soil microbe quantities of the fixed and semi-fixed sand dunes are the most , and reduces gradually with increase of the soil depth. Microbe quantities of the different seasons are different, that is Summer >Autumn > spring > winter. And the four kinds of soil microbe quantities dynamic change differently each season in the respective soil layer of each plots, the bacteria and azotobacter quantities are the most in summer and autumn, whereas actinomyceto and fungi quantities are the most in autumn and summer, and the four kinds of microbial quantities are the least in winter .2. MBC, MBN and microbe quantities are positive correlation, that is GX>GZ>GW>BZ>BW>L. The MBC and MBN content of the different depth is different. Except the moving dunes, the content of MBC、MBN is the highest in the of top layer in the other kinds of plots, and reduce sharply with the increase of the soil depth. The MBC and MBN content of the moving dunes is nearly the same each season, but there are prominent and even extremely prominent seasonal differences in the other plots. MBC, MBN content is most high in autumn, secondly is summer, spring, the content is the lowest in winter.3.The three soil hydrolases (urease, protease and invertase) have a prominent difference (P<0.05) in different kinds of plots, that is GX>GZ>BZ>GW>BW>L. Except moving dunes, in the other kinds of plots, soil hydrolase activity is reduced with the increase of the soil depth, and compared with under 3cm soil layers, the top layer is the prominent or extremely prominent difference. At the same time, three soil hydrolases are also different each season.As to hydrolase, the polyphenol oxidase activities in different kinds of plots are that GX>GZ>GW>BZ>BW>L. The oxidase activities,which are much similar to hydrolase, are reduced with the increase of the soil depth, and there are the seasonal differences at the same time.4. Soil moisture and pH are different in the different kind of plots, but not obvious. As the moving dunes evolved towards the semi-fixed sand dunes, fixed sand dune, the biological soil crusts emerged. In the process of development, the coarse sand content decreased gradually, fine sand content gradually increased, and when there were biological soil crusts, the silt emerged. From section plane of the structure, biological soil crusts should better improve soil particle on the top layer than below the soil surface.With the sand dune fixed and biological soil crusts emerged and developed, except total potassium, the soil organic carbon, organic matter, total nitrogen, total phosphorus and other soil nutrients substantially increased. Biological soil crust increased soil nutrients, improved soil fertility. And the range of soil nutrient content with the seasonal changes were obvious differences.5. Bacteria and the total number of soil microbes have correlation significantly with MBC、MBN, the rest up to very significantly. The soil microbe quantities have a positive correlation with soil enzyme activity. The surface soil organic matters, organic carbons, total nitrogens as well as total phosphorus have different degrees of relevance with soil microbes,soil enzymes activity and soil particles. The results show that soil microbes, soil enzymes and the various soil factors are interdependent and affect each other.更多还原