不同退化程度人工梭梭林土壤微生物数量动态及土壤酶活性研究

发布时间：2018-07-03 14:46

本文选题：民勤绿洲 + 人工梭梭林　；参考：《兰州理工大学》2017年硕士论文

【摘要】：民勤绿洲处于腾格里沙漠和巴丹吉林沙漠之间,是沙尘暴在我国西北地区的必经通道,它阻挡了两大沙漠合并,同时也阻挡住西来的沙尘暴,具有十分重要的生态战略地位。近年来,人们对地下水资源无节制的开采利用,加上自然原因,导致民勤绿洲周缘人工梭梭林大面积衰败退化,生态问题日益严重,所以对退化人工梭梭林地进行系统的研究具有十分重要的理论和实践意义。本研究以民勤绿洲边缘4个不同退化程度人工梭梭林地土壤为研究对象,通过野外调查和室内分析,研究了不同退化程度人工梭梭林地土壤微生物数量、土壤酶活性以及土壤养分的时空动态,并分析了它们3者之间的相关性,为探索民勤绿洲边缘人工梭梭林的退化机制,以及生态系统的植被恢复与重建提供参考依据。主要结论如下:1.土壤三大类微生物数量有明显的垂直分布规律:土壤微生物集中分布于0-10cm土层,并随土层的加深而递减。不同季节时间,土壤三大类微生物数量存在明显差异,季节动态表现为:春季低,夏季高,秋冬季低。在所有的退化人工梭梭林地中,细菌占据主导地位,放线菌次之,真菌最少。不同退化程度细菌数量和微生物总数量大小关系为:SLDNDMDSD,放线菌和真菌数量大小关系为:NDSLDMDSD。2.土壤脲酶、蔗糖酶和过氧化氢酶活性随土壤深度的加深呈减少的趋势,结皮层土壤酶活性最高,土壤多酚氧化酶活性垂直分布不明显。不同退化程度人工梭梭林地0-10cm土壤脲酶、蔗糖酶、过氧化氢酶和多酚氧化酶活性表现出明显的季节动态,土壤脲酶、蔗糖酶和过氧化氢酶活性季节动态表现为:在结皮层,春季高,夏季、秋季和冬季低;在1-10cm,夏季高,春季、秋季和冬季低。土壤多酚氧化酶活性季节动态表现为:春季高,夏季低,秋季高,冬季低。随退化程度的增加,除过氧化氢酶外,0-10cm土壤酶活性呈递增趋势,10-40cm各层次,各退化程度间大小规律不明显。3.土壤有机质、全N、速效P和速效K含量垂直分布规律明显,在结皮层最高,随土壤深度的加深呈递减趋势。不同季节时间,0-10cm土壤有机质、全N和速效P含量均存在差异,季节动态表现为:夏季高,春季、秋季低,速效K含量变化幅度较小,总体季节动态不明显。随退化程度的增加,结皮层土壤有机质、全N、速效P和速效K含量呈递增趋势,1-40cm各层次,各退化程度之间大小规律不明显。4.土壤细菌数量与脲酶、蔗糖酶和过氧化氢酶活性,以及有机质、全N、速效P和速效K含量均呈现极显著正相关(p0.01);脲酶、蔗糖酶和过氧化氢酶活性与土壤有机质、全N、速效P以及速效K含量呈极显著正相关(p0.01)。这说明土壤细菌的数量、脲酶、蔗糖酶和过氧化酶活性与土壤养分间存在密切相关关系,而且土壤酶具有相对的稳定性,因此可将土壤细菌数量、脲酶、蔗糖酶和过氧化酶活性的高低作为指标来评价民勤绿洲周缘人工梭梭林地土壤肥力水平。
[Abstract]:Minqin Oasis is located between Tenggri Desert and Badain Jilin Desert. It is the necessary passage of sandstorm in Northwest China. It blocks the combination of two deserts and also prevents the sandstorm from coming from west. It has a very important ecological strategic position. In recent years, the unrestrained exploitation and utilization of groundwater resources, coupled with natural causes, have led to the decline and degradation of a large area of the artificial Haloxylon ammodendron forest around the Minqin oasis, and the ecological problems are becoming more and more serious. Therefore, the systematic research on degraded artificial ammodendron woodland is of great theoretical and practical significance. In this study, the soil microbes of four different degradation degree soil of Ammodendron ammodendron were studied by field investigation and indoor analysis on the edge of Minqin oasis, and the soil microorganism quantity of different degradation degree of Ammodendron ammodendron plantation was studied. The temporal and spatial dynamics of soil enzyme activity and soil nutrients were analyzed, and the correlation between them was analyzed, which provided a reference for exploring the degradation mechanism of the artificial Haloxylon ammodendron forest on the edge of Minqin oasis and the vegetation restoration and reconstruction of the ecosystem. The main conclusions are as follows: 1. The number of soil microorganism has obvious vertical distribution law: soil microorganism is concentrated in 0-10cm soil layer and decreases with the deepening of soil layer. In different seasons, there were obvious differences in the number of soil microbes, and the seasonal dynamics were as follows: low in spring, high in summer and low in autumn and winter. In all the degraded artificial ammodendron woodlands, bacteria dominated, actinomycetes took second place, and fungi were the least. The relationship between the number of bacteria and the total number of microbes was: SLDNDMDSD.The relationship between the number of actinomycetes and the number of fungi was: NDSLDMDSD.2. The activities of urease, sucrase and catalase in soil decreased with the deepening of soil depth. The activity of soil urease, sucrase and catalase decreased with the deepening of soil depth. The activities of urease, sucrase, catalase and polyphenol oxidase in 0-10cm soil of different degenerative degree showed obvious seasonal dynamics. The seasonal dynamics of soil urease, sucrase and catalase activities were as follows: in the cortical layer, the soil urease, sucrase and catalase activity showed seasonal dynamics. Spring high, summer, autumn and winter low; at 1-10 cm, summer high, spring, autumn and winter low. The seasonal dynamics of soil polyphenol oxidase activity were high in spring, low in summer, high in autumn and low in winter. With the increase of degradation degree, the soil enzyme activity in 0-10cm soil showed an increasing trend with the increase of degradation degree. The vertical distribution of soil organic matter, total N, available P and available K was obvious, which was the highest in the crust, and decreased with the deepening of soil depth. The soil organic matter, total N and available P contents were different in different seasons. The seasonal dynamics were high in summer, low in spring and autumn, small in available K content, and not obvious in total seasonal dynamics. With the increase of degradation degree, the contents of organic matter, total N, available P and available K in the soil increased from 1-40 cm to 40 cm. The number of soil bacteria was positively correlated with the activities of urease, sucrase and catalase, as well as the contents of organic matter, total N, available P and available K (p0.01), and the activities of urease, sucrase and catalase were correlated with soil organic matter. The contents of total N, available P and K were positively correlated (p 0.01). This indicates that the number of soil bacteria, the activities of urease, sucrase and peroxidase are closely related to soil nutrients, and that soil enzymes have relative stability, so that the amount of soil bacteria, urease, The activities of sucrase and peroxidase were used as indexes to evaluate the soil fertility level of the artificial ammodendron plantation around Minqin oasis.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S714

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