Relationships Between Soil Fauna And Soil Microorganism Communities In Farming Black Soil With Different Interventions

The soil fauna and soil microbe are important decomposers in ecological system, and they also have important influence on structure and function of ecological system. The study on interrelation between meso-micro soil fauna and soil microbe is the key content and development trend of current soil ecological study and it is of great significance for promoting biological action mechanism of Chinese soil ecological system and revealing ecological geographic rules. Currently, influenced by many factors, the black soil in Heilongjiang Province suffers color fading, reduction of stored nutrients, and reduction of moisture and fertility preservation ability; the black soil gradually degrades, the soil environment is damaged, the ecological function reduces, and the biological diversity suffers great threat. This study aims at providing scientific basis for study on black soil degrading mechanism.This study aims at giving a comprehensive and systematic analysis on interrelation between meso-micro soil fauna and soil microbe from perspective of community ecology, so as to lay a foundation for deeply discussing the mutual action mechanism between soil fauna and soil microbe and promoting development of Chinese social bio-ecology as well as provide basis and data support for management and recovery of degraded arable ecological system. As for current degradation situation of black soil, this paper takes degraded arable black soil in Heilongjiang Province as study area and makes a systematic investigation on characteristics of community structure of meso-micro soil fauna and soil microbe in degraded black soil under different intervention; combines traditional soil organism community biodemography with principal component analysis to analyze influence of ecological factors on distribution of meso-micro soil fauna and soil microbe. Furthermore, this paper makes use of curve estimate model to carry out quantitative analysis on interrelation between meso-micro soil fauna and dominant species of soil microbe in individual number and density; applies grey correlation degree method to make a comprehensive analysis on interrelation between functional soil fauna community and functional soil microbe community; uses binary variable correlation analysis to carry out study on interrelation between diversity of meso-micro soil fauna community and diversity of soil microbe community.Through investigation on structure of meso-micro soil fauna community in degraded arable black soil,14,210 meso-micro soil fauna are found and they belong to 2 phylums,6 classes,14 orders,47 families, and 54 species. The individual average density of meso-micro soil fauna is 14802.08/m2; the individuals of Acarina have the largest density, accounting for 59.08% of individual density of meso-micro soil fauna, followed by collembolan and diptera, which respectively account for 32.27% and 3.55% of individual density of meso-micro soil fauna. Under different intervention, there is an obvious change in density of various meso-micro soil fauna, and the change degree of density is arranged as a descending order:sample soil with organic fertilizer, sample soil with semi-organic fertilizer, contrast sample soil, sample soil with inorganic fertilizer, sample soil with herbicide, and sample soil with insecticide. The dominant species of meso-micro soil fauna include Oribatida, Mesostigmata, Prostigmata, and Isotomidae. It is shown through clustering analysis and multi-dimensional scaling analysis that the meso-micro soil fauna is divided into 3 kinds.Through investigation on structure of soil microbe community in degraded arable black soil,6.53×106/gdry soil soil microbe are found, including 12 kinds of bacteria,7 kinds of actinomycete, and 5 kinds of fungus, which are 24 kinds in total. The individual average density of soil microbe is 8.43×1011/m2, the individual average density of bacteria is 7.08×1011/m2, accounting for 84.07% of individual density of soil microbe; the individual average density of fungus is 1.24×1011/m2, accounting for 14.72% of individual density of soil microbe; the individual average density of actinomycete is 1.02×1010/m2, accounting for 1.21% of individual density of soil microbe. Under different intervention, there is an obvious change in density of various meso-micro soil microbe, and the change degree of density is arranged as a descending order:sample soil with organic fertilizer, sample soil with insecticide, sample soil with semi-organic fertilizer, sample soil with inorganic fertilizer, contrast sample soil, and sample soil with herbicide. The dominant species of soil microbe include Bacillus, Azotobacter, Streptomyces, Rothia, Bacterionema, Aspergillus, Penicillium, Rhizopus, and Fusarium. It is shown through clustering analysis and multi-dimensional scaling analysis that the soil microbe is divided into 4 kinds.Through quantitative analysis on relation between meso-micro soil fauna community and soil microbe community based on curve estimate model, it is shown that there exists correlation between meso-micro soil fauna and soil microbe in terms of total quantity of individuals and density; except for fungus, there also exists correlation between meso-micro soil fauna group and soil microbe group in terms of total quantity of groups. Under 6 different interventions, there exists correlation between meso-micro soil fauna and soil microbe in terms of quantity of individuals and density. In all modes of intervention, there exists correlation between bacillus and isotomidae in terms of density and it is able to obtain regression equation; as for other parts of meso-micro soil fauna and soil microbe, there exists correlation in different modes of intervention, and it is able to describe them through different regression equations. In sample soil with organic fertilizer, the correlation between meso-micro soil fauna and soil microbe is the most complicated; in sample soil with insecticide and herbicide, the correlation between meso-micro soil fauna and soil microbe is relatively simple.Through study on interrelation between functional meso-micro soil fauna and functional soil microbe by use of grey correlation degree method, it is shown that there exists the highest mutual correlation degree between meso-micro soil fauna and soil microbe in sample soil with organic fertilizer, sample soil with semi-organic fertilizer, and contrast sample soil, which have the most complicated composition relationship of ecological system and the highest stability of ecological system; however, in sample soil with inorganic fertilizer, sample soil with herbicide, and sample soil with insecticide, there exists the lowest mutual correlation degree between functional meso-micro soil fauna and functional soil microbe, which have a simple composition relationship of ecological system and the poorest stability of ecological system. This shows that the mutual relation between functional meso-micro soil fauna and functional soil microbe can be used as indicative factor for health of degraded ecological system.Through study on mutual relation between diversity of meso-micro soil fauna community and diversity of soil microbe community by use of binary variable correlation analysis method, it is shown that the overall relation between meso-micro soil fauna and soil microbe is mutualism, the meso-micro soil fauna and soil microbe can mutually promote the healthy development of respective community, which is of great significance for maintaining stability of ecological system’s function. In the areas with organic fertilizer and semi-organic fertilizer, the relation between meso-micro soil fauna and soil microbe is mainly a inhibiting one; however, in the areas with inorganic fertilizer, herbicide, and insecticide, the relation is mainly a syntrophism one. The relation between meso-micro soil fauna diversity and soil microbe diversity is of important significance for repair of degraded ecological system.The study on relation between soil fauna and soil microbe is an important foundation for functional study of soil fauna and soil microbe; however, the current study on their mutual relation is still weak. Most of domestic and foreign ecologists’ studies are carried out on interaction relation between specific soil fauna and soil microbe based on traditional biostatistics method under homogeneous background. This study takes the arable black soil under different interventions as background; on the basis of large quantity of sampling survey and experimental treatment, it adopts PCA, curve estimate model, grey correlation degree and other mathematical methods to carry out qualitative and quantitative analysis on inner relation between two communities from different perspectives, and carries out contrastive analysis on their relation under different intervention for the purpose of providing data support for management and recovery of degraded arable black soil ecological system.