| The physical and chemical index and microbial community diversity and composition of composting treatments adding different proportion of rice straw stalk were chosen as object in our study. The Metagenomics and the latest Miseq 16S rDNA high-throughout sequencing technology used as the major technology, the physical and chemical parameters changes and its effects on microbial communities in the process of pig manure composting were analyzed. The experiment treatments were:add low level of straw and regulating C/N for 15, add a high amount of straw regulating C/N to 20 and pure pig manure (C/N is 11.44). The major results are shown as follows:(1) During a 33-day composting, high straw addition treatment can accelerate the rotten of pig manure composting. In the end of the composting, the moisture loss velocity of the pure pig manure compost was greater than that of the rest treatments, the pH, EC and E4/E6 value were conform to the standard of rotten compost. The C/N and T value results showed that the treatment which adding a high amount of straw has a better effect of compost rotten, and it is advantageous to the rotten of pig manure composting quickly. The composting can improve the total phosphorus content in the compost. The cellulose and hemicelluloses in the pure pig manure treatment have the highest degree of degradation, the lignin in the three treatments are hard to degrade.(2) The samples collected from various stages of pig manure compost were teated through high-throughput sequencing technology, gained 18203 reads in total and the sequencing depth (more than 81%) indicating that the sequence of each sample may reflect the real situation of microbial community in the compost. Alpha diversity showed that the treatment of adding high amount of straw significantly increases the richness and diversity of the microbial community compared with the pure pig manure compost. In the heating and thermophilic phase, the richness and diversity index of the treatment of adding high amount of straw were the highest. And the Shannon index, ACE index and Chao 1 index were 6.25, 14715.38 and 8460.76. Their order are both high straw addition>low straw addition>pure pig manure compost. The analysis based on the community structure of phylum level showed that along with the composting process, Firmicutes (23-92%) is always dominant, followed by Proteobacteria(4-38%) and Actinobacteria (2-20%). What’s more, there is a large quantity of unclassified bacteria (0.2-10%) exist. The 15 samples in the various stages of three treatments of pig manure compost can be roughly divided into 6 clustering through distance heat-map.(3) Different treatments had vital influence on microbial community, and between the individual samples, there are certain differentiation. In the pig manure composting, the temperature has a significant negative correlation with the sequencing coverage, the moisture content was significantly positively related with Shannon index. On the whole, during the period of composting, the material changes had a significant effect on the richness and diversity microbial community. |
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