Biological Optimal Monitoring And Quantitive Assessing Of Soil Health In Typical Grassland

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".