围封年限对荒漠草原植物、土壤及微生物化学计量特征的影响

发布时间：2018-05-29 19:57

本文选题：荒漠草原 + 围封年限　；参考：《宁夏大学》2016年硕士论文

【摘要】：封育禁牧作为重要的生态恢复措施,所带来的生态效应已逐渐成为恢复生态学研究的焦点。由于植被-土壤-微生物系统C、N、P循环是在生态系统内部之间相互转换的,系统研究植物-土壤C、N、P在植物与土壤中的交换过程与格局,深入理解封育禁牧生态恢复过程中系统各组分之间的化学计量学协变关系,对揭示荒漠草原生态系统稳定性维持机理具有重要意义。本研究以宁夏境内荒漠草原为研究对象,通过对比分析未围封、围封5、8、12、15年样地植物、土壤碳、氮、磷以及土壤微生物量碳、氮与土壤酶活性的变化过程与规律,分析荒漠草原不同围封年限对植物、土壤与土壤微生物的影响。得到如下研究结论：1.围栏后,荒漠草原在消除放牧干扰的情况下,植物的生长得到一定的恢复,主要表现为植物地上部分的生物量与放牧样地的植物地上生物量相比,围封5、8、12和15年样地的植物地上生物量均呈增加的变化趋势。植物的高度和盖度等植被特征也表现出相似的变化规律,高度、盖度、地上生物量均随着围封年限的延长表现出先增加后减少的变化趋势。围封样地的优势种植物地上部分碳、氮含量均高于未围封样地,且围封样地的优势种植物地上部分C：P比值与N：P比值均高于未围封样地。2.随着围封时间的延长,土壤容重先减小后增大；土壤含水量则表现出相反的变化规律,即先升高后降低；同时,围封使不同封育年限的土壤pH值降低。3.荒漠草原采取围封措施以后,土壤有机碳含量、全氮含量和全磷含量均高于未围封样地,且随着围封时间的变化表现出相似的变化规律,即：围封12年时,含量最高,之后,含量出现降低的趋势。土壤微生物量碳和微生物量氮均高于未围封样地,这说明在荒漠草原采取围封措施可以促进土壤微生物的活动,从而提高微生物量。同时,土壤微生物量C：N比值随围封时间的延长先增大后减小。4.土壤脲酶活性、土壤蔗糖酶活性、土壤过氧化氢酶活性及土壤碱性磷酸酶活性并未表现出明显的规律。土壤酶活性的大小受众多因素的影响,关于这一方面的原因,仍需要进一步的探讨。5.从处于围栏状态下的植物、土壤与微生物之间的关系来看,彼此间的相互作用可对草地的恢复起到一定的改善效果。上述研究结果表明,宁夏荒漠草原在围栏封育早期阶段,植被恢复、土壤养分改善效果显著。植被生产力发生相应的改变,具体表现为在围封超过12年以后开始出现下降趋势,而这种规律同样适用于土壤养分方面。
[Abstract]:As an important ecological restoration measure, the ecologic effect has been the focus of restoration ecology. As the vegetation soil microbial system C, N and P cycle are interconversion between the ecosystem, the exchange process and pattern of plant soil C, N, P in plant and soil are systematically studied, and the seal is deeply understood. The chemometrics covariant relationship between the components of the system during the restoration of animal husbandry ecological restoration is of great significance to reveal the stability maintenance mechanism of the desert steppe ecosystem. In this study, the desert steppe in Ningxia was taken as the research object. The soil carbon, nitrogen, phosphorus and soil microstructures were compared and analyzed by the comparison and analysis of the unsealed 5,8,12,15 year plots. The change process and law of biomass carbon, nitrogen and soil enzyme activity, and analyze the effects of different enclosure years on plants, soil and soil microbes in desert steppe. The following conclusions are obtained: 1. after enclosure, the growth of plants in the desert steppe is restored to a certain extent in the condition of eliminating grazing interference, mainly as the upper part of the plant. Compared with the aboveground biomass of the grazing land, the aboveground biomass of the enclosed 5,8,12 and 15 year plots showed an increase in the aboveground biomass. The vegetation characteristics, such as height and coverage of plants, also showed a similar change, and the height, coverage and aboveground biomass all increased first and then decreased with the prolongation of the enclosed years. The content of carbon and nitrogen in the upper part of the predominant plant was higher than that in the non enclosed land, and the ratio of the C:P ratio and the ratio of N:P to the superior species of the predominant plant were higher than that in the non enclosed land, and the soil bulk density decreased first and then increased with the enclosing time, while the soil moisture content of soil soil showed the opposite change rule. At the same time, the soil organic carbon content, total nitrogen content and total phosphorus content of soil organic carbon content, total nitrogen content and total phosphorus content were higher than that of non enclosed land after the enclosure measures were adopted in the soil pH value of.3. desert grassland. The amount of soil microbial biomass carbon and microbial biomass nitrogen were higher than that of the non enclosed land, which indicates that the enclosure measures in the desert grassland can promote the activity of soil microbes and increase the microbial biomass. At the same time, the soil microbial biomass C:N ratio increases with the prolongation of the enclosure time and then reduces the activity of soil urease in the soil of.4. and soil. Invertase activity, soil catalase activity and soil alkaline phosphatase activity did not show obvious regularity. The size of soil enzyme activity was influenced by many factors. In this respect, further discussion on the relationship between.5. and the relationship between soil and microorganism and the relationship between soil and microorganism still needed to be further explored. The interaction can improve the restoration of grassland. The results showed that the effect of vegetation recovery was remarkable in the early stage of enclosure of the Ningxia desert grassland, and the effect of soil nutrients was improved. The sample is suitable for soil nutrients.
【学位授予单位】：宁夏大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：Q948.1

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