The Simulation Study On Effect Of Pig Wastewater Leakage To The Content Of Soil Organic Matter And Microbial Diversity

The number of pig production in China is largest in the world, according to statistics,667million pigs was produced in2010, accounting for49%pig production of the whole world. At the same time, the amount of pig manure and wastewater increased fast and became a primary pollution source in recent years. Under the background, the pig wastewater leakage flowing into soil system and leading to soil and groundwater pollution has occurred everywhere, because of the characteristic of great quantity, flowing easily and hard to storage. Therefore, it is important to explore the rule of pig wastewater leaching in the soil system and its effect about soil bacterial biomass and microorganism diversity so that the potential of groundwater pollution could be evaluated. In this paper, a simulated soil column experimental system was designed and the latest metagenomics method combined with conventional determination method was adopted to study how some soil characteristics and soil bacterial biomass or microorganism diversity were affected. The main conclusions were as follows:Accord to determination in this study, the pH value in each layer of soil was near7and microorganism in the pig manure can reduce the pH value of soil and improved soil quality. Water ratios of soil in each layer were from20.37%to27.92%with a small fluctuation range. TOC value of soil changed in a large fluctuation range, the Maximum was the value of soil with manure at the depth of270cm in group MM,28.1810g/kg, while the minimum was the value of soil without manure at the depth of180cm in group MW,1.0177g/kg.The PCR products obtained in this study were high yield and high specificity and the fragment length of approximately200bp was the target bands, without significant non-specific amplification. This way to get PCR products laid the foundation for the further study of microbial species, microbial environment and provide protection. The sample tags abundance analysis show that the abundance of unique tag was one, indicating that most of the unique tag in the sequencing process only can be measured once, what means the the sequencing data were high accuracy.Microbial DNA concentration negatively related to soil depth. Fecal pollution of the soil decreases with the increasing of soil depth. Microbial biomass in the soil more at the depth before60cm, and only small amounts of microorganisms after the depth of90cm.Microbial population in manure and the surface were much more than the bottom. Under the function of the soil as a filter, the species and quantity of microorganisms in the FenF appeared regular change, and this change was reduced regularity. Prevotella, Escherichia, Geobacter and Streptomyces played an important role in distinguishing different soil samples.The soil plays an important role in filtering microorganisms. When the soil surface is polluted by animal manure, soil at the depth of50cm can effectively reduce the number and species of microorganisms. If the farms need to take groundwater or use the soil to reduce microbial, it’s better to reach the soil at the depth of50cm at least.