【作者】 赵吉；

【导师】 杨劼；

【作者基本信息】 内蒙古大学 ， 生态学， 2005， 博士

【摘要】 土壤是地球上关乎生命质量的和有限的自然资源,它可以维持陆地生态系统的正常功能并综合体现其物理、化学和生物学因素间的内在平衡性。人们认识到土壤作为地球生物圈的一个关键的组成要素,不仅具有生产食物和纤维的功能,而且维持着当地、区域,乃至全球的环境质量,土壤资源的质量和健康的评估已受到普遍关注。当前,土壤退化和土壤污染现象日趋严重,土壤生态系统结构和功能紊乱,危及人类的健康与生存。土壤质量和土壤健康与未来农牧业的可持续发展及环境质量息息相关。土壤的功能性是土壤质量的核心内容。土壤健康可概括为:“土壤动态生命系统具有的维持其功能的持续能力”。土壤也是地球上动态的、有生命活力的和最复杂的自然复合体,土壤微生物是土壤生物区系的关键功能性要素,控制着天然物质和污染物质的转化和矿化作用,驱动着土壤生态系统物质循环和能量流动过程。土壤中含有大量的微生物,它们通过改变能量利用策略和调整其群落生物量、活性和结构以适应环境胁迫条件。 背景土壤或参比土壤是土壤健康对比研究中的理想途径,以中温型典型草原围栏保护20年的原生群落为健康参比,测定分析不同放牧退化程度下土壤微生物的数量、生物量、酶的活性等土壤生物指标。分析表明,土壤微生物生物量与总有机C、全N均表现出很好的相关性,可以作为评价土壤肥力状况的生物学指标;土壤酶的总体活性可以用来表征土壤肥力水平。围栏封育或适度放牧有助于提高退化草原土壤微生物的活性,有助于土壤微生物功能的逐步恢复。近年来人们对草场不合理的过度利用已导致土壤微生物的活性明显降低。就内蒙古草原而言,从东向西,随着降水减少或辐射增强,土壤肥力水平和微生物活性总体呈现地带性下降格局。 文中探讨了土壤健康的内涵及其评价的理论和方法,系统提出了新的土壤健康评价的生物学指标体系,包括:土壤生物的生物量、生物活性、生物多样性和生物功能性四个方面。以土壤生态系统能流和碳流为线索,依照生态能量学优化原理,通过因子分析等数学方法筛选出标志土壤生物学质量的9个优化监测指标或衍生参数,这些微生物生物量水平的基本参量作为土壤健康评价的量化指标和敏感参数。其中,量值指标有:微生物生物量-C(C_bio)、基础呼吸量C(C_BR)、潜更多还原

【Abstract】 Soil is a vital and finite resource that can maintain to the function of terrestrial ecosystem and represents a unique balance between physical,chenical and biological factors. Evaluating the quality and health of our soil resources has been stimulated by increasing awareness that soil is a critically important component of the earth’s biosphere; function not only in the production of food and fibre but also in the maintenance of local, region, and global environmental quality. The phenomenon of soil degradation and soil pollution has becoming more serious, and structure and function of soil ecosystem are disorderly, jeopardize human health and existence. Soil quality and soil health determine the sustainable productivity of biology and quality of environment in future. Soil unction is the focus of soil quality. Soil health can be chief defined as "the continued capacity of soil to function as a vital living system".Soil is dynamic, living and the most complicated compound on the earth, the microbial components in soil biota is key functional factors that control the transformation and mineralization of natural compounds and xenobiotics, promote the material circulation and energy flow of soil ecosystem. The soil microbiota, existing in extremely high density and diversity, rapidly modify the energetic performance and activity rates to changing environmental conditions, the microbial consortium possesses the ability to accommodate environmental constraints by adjusting biomass, activity rates and community structure. Some microbiological basal parameters and derived quotients can be used as sensitive and quantitive bioindicators for monitoring and evaluating soil health.Control sites for comparison of results are the best solution for evaluation of soil health, the plant original community by fencing reserve for 20 years that is chosen as an ideal control site of non-contaminated and background soil in the steppe. Gather soil samples under different degradation degree, some soil bioindicators such as each group quantity of microorganism, microbial biomass-C, respiration rate and enzyme activities are determined. The results show that soil microbial biomass is relate with soil organic carbon and total nitrogen, and can be regarded as an indicator to evaluate the soil fertility. Total enzyme activity in soil play an important role in evaluating the soil fertility. Fence approach may promote soil microbial activities in degraded grassland, and is helpful to restore soil health. Excessively grazing induce obviously reduce of soil microbial activities in recent years. As regards the steppe, with the change of the moisture and temperature condition, the soil fertility and microbial biomass relatively decline from the east to westward.In this paper, theory and approach of "soil health" is advised, a new evaluating system of soil health and soil biological quality is proposed, and the biological indicators contain: (1) quantity, (2) activity, (3) biodiversity, and (4) functionality. Based on the process of energy flow and carbon exchange in soil ecosystem and ecological energy optimization theory, a new approach to interpretation of results of the simplemicrobial biomass and respiration measurements in the soil microbiology is proposed. The principle is based on nine microbial basal and derived parameters, which are standardized and then plotted into sunray plots.. The results show that nine parameters provide enough information for evaluation of the status of the soil microorganisms and, thus, for evaluation of the soil heath. The usage of basal parameters: microbial biomass-C (Cbk>), available organic-C (Cext), basal respiration-C (Cbr), potential respiration-C (Cbr), and derived parameters: metabolic quotient (CBR/Cbi0; or qCC^), respiratory activation quotient (Cbr/Cpr), potential respiration quotient (Cpr/Ciho), mineralization quotient (Cext/Cbi0), and Humic Efficiency (Cext/CBR). Above derived parameters can be use as eco-physiological quotient for assessing soil health. The approach use very simple measured parameters of biomass-level assays to obtain maximum information about the soil microorganisms. Microbial parameters have showed great potential to become the early warning and quantity indicators for monitoring the stresses or perturbations in soils ecosystems. Hierarchical cluster analysis showed Cbio, Cbr, qCC>2 and qR (Cbr/Cpr) is the minimum data set for evaluating soil health.In typical steppe of Xilin river basin and Huangfuchuan basin in Inner Mongolia, soil health quality and biological quality under the way under different degree of degradation and different land utilize have analyzed. Discriminant analyzes by sunray graph through these indexes and parameters of set up that prove have good appraisal effects. The results showed that Y2 (control site of fencing reserve 20 year)as an ideal control site displays very high content of the microbial biomass and the lowest metabolic quotient of all soils, it is the health soil.Yl (background site of fencing reserve 20 year never used) display highest respiration and available organic carbon, and higher biomass, only mineralization quotient a little high.Y3 (site of fencing reserve 5 year) is a average leavl.Y4 (site of nature grazing out of fencing) display below-average microbial biomass with rather lower basal mineralization activity. The humic efficiency is lower by the lack of the appropriate substrate in the soil. The microbes are clearly exposed to the stress effect; because the energetic requirements are higher. Y5 (site of excessive grazing out of fencing) display lower microbial biomass carbon and available organic carbon, it is not better than Y4; however, they are not be healthy. Analyze synthetically that shows, different status of soil health under the different way of land utilized, ecology physiological state of soil microorganism according to agricultural land, arbor forest land, original herbage land, bush forest land be decrease sequentially.Assessing system of soil biological quality is proposed firstly, key indexes of for assessing soil health contain the eco-fertility, eco-physiology, and eco-resilience parameters has selected. The preliminary graded standard of soil health in steppe has set up. This research has offered the biological basis of land management and soil degradation, and offers the scientific method for studying on toxicology of the contaminated soil, and gets the foundation for the formulation of "Health standard of agricultural soil".更多还原