Characteristics Of The Soil Animal Communities And Their Response To Soil Heavy Metal Pollution

Soil animals are animals living in the soil, which have regular periods to pass the soil, or even live in the soil all through their lives that rely on the soil environment, and also have certain influence on the soil. The main research area of soil zoology includes soil animal taxonomy research, type distribution and quantity statistics research, individual species ecology research, the reciprocity of soil animal and edaphon research, the function of soil animal in the flow between matter and energy of ecosystem research, the instruction of soil animal to soil pollution research, as well as the application of soil animal in agricultural production domain research, and so on. Modern soil zoology research has the biological productivity and the relations between human and their environment on stage. The biological decontamination of soil pollution, and the biological monitoring and evaluation of environmental quality, all of which will be the most practical significance of the frontier disciplines.The sewage irrigation area along the Huafei River in Kaifeng City is made as the studying area in the paper, and along the river there are 16 emplaced samples. The collection of the soil samples was done in April, 2007, and the soil animal samples were collected respectively twice in April and September in 2007. Based on the data of soil animals and soil physicochemical properties, the paper analyzes the Characteristics of the soil animal communities in the sewage irrigation area in way of soil zoology and ecological theory and metering method, and concludes the response of soil animals to the soil heavy metal pollution.The five parts included in this paper,PartⅠThe mainly introduced and analyzed items are the soil zoology research process, the present situation, the existence question and the future main research areas, which at the same time points out the vital significance of the research on polluted farmland animals and their response to the soil heavy metal pollution.PartⅡAn overview of the natural profile and river water quality of the sewage irrigation area are made in this part. They are the major environmental factors that impact the composition, number, and characteristics of soil animals. PartⅢThe survey methodology, soil animal identification methods, laboratory analysis and data-processing method are introduced.PartⅣBy counting the quantity of soil animal individuals and groups in each sample area, this part analyzes the dominant and frequent soil animal groups, biodiversity of the soil animal communities, horizontal and vertical distribution in soil profile, and similarity of soil animal communities, the heavy metal concentration of earthworms. The relationship between soil animals and soil physicochemical properties is also analyzed. The soil animals′response to heavy metal pollution is discussed.PartⅤSome main conclusions are summarized as follows,(1) The total of soil animals in spring are 4123 which belong to 81 groups, 6 phyla. The dominant group is Nemata. The number of common groups is 12, including Isotomidae, Neanuridae, Onychiuridae, Enchytraeidae, and so on. In autumn, the total number of soil animals is 2525 which belong to 62 groups, 4 phyla. The dominant groups are Nemata and Isotomidae. The number of common groups is 17, including Staphylinidae, Enchytraeidae, Periohmanniidae, Hypogastruridae, and so on.(2) The relationship between soil animals and the major soil physicochemical properties which include organic matter, pH and the soil texture, is not obvious. The soil physicochemical properties′impact on soil animals is minor because of heavy metal pollution.(3) The total number of soil animals in spring is larger than that in autumn, but the differences between the numbers of samples are more notable than those in spring. The groups in autumn are more than those in spring, and the differences between samples are not significant. Both the individual numbers and groups have certain negative correlations with the composite indexes of heavy metal pollution. This shows that the heavy metal pollution is the important factor that caused the number of individuals and groups to reduce.(4) The vertical distribution of soil animals is strongly disturbed by heavy-metal contamination, but the individuals and groups in response to that is inconsistent. In severe contaminated areas, the surface aggregation are weaker, and reverse distribution are obvious. In spring the reverse distribution are obvious while that in autumn are normal.(5) The DG, H'and E have shown a consistent trend, the greater diversity the higher degree of richness. The e and C are on the contrary trend, the higher uniformity the lower dominance. All the indexes of DG, H, E and e in autumn are higher than those in spring, and the scope of changes are smaller, while the index of C smaller than that in spring. The three similarity coefficients Cs, Sm and q have lower values, and their order is Cs>Sm>q. This shows that there is a low level of similarity between samples.(6) There is a notable positive correlation between the enrichment of heavy metals in earthworms and that in soil. The order of these enrichment coefficients in earthworms is Ni>Cd>Cu>Pb>Zn. These coefficients of Nickel and Cadmium are larger than 1, which shows a strong enrichment. Soil animals are a good biological indicator of heavy metal contamination of soil. The soil animal distribution and characteristics of communities can be evaluated as a pollution indicator. That is best to choose the dominant groups Nemata as a major indicator and best in spring when carrying out pollution monitoring. The heavy metal content in earthworms can be used as the main indicator that reflects the heavy metal pollution levels.