| The increasing population of Chinese nation is a main pressure on agriculture production, it may require increasing the amount of chemical fertilizer for boosting production. However, the unreasonable fertilization can lead to changes in microbial diversity, abundance and activity of soil microbes and specific functional microbes. Thus, these acute changes can affect the soil fertility and functions. It may further influence on the food security of our country. On the other hand, it may limit the productivity improvement of the paddy ecosystem. And fertilization will affect the methane and other greenhouse gas emissions, increasing in atmospheric greenhouse effect. Bacteria and fungi are the main microorganisms in soil, methanogens and methanotrophs are important functional microbes related to CH4. The research of microbial diversity can reveal the response of soil microorganisms under different fertilization modes, increase our knowledge of the relationship between microorganisms and fertilization modes, so as methane emission of paddy soil.An experiment was organized on paddy red soil with different fertilization treatments for 30 consecutive years at Jiangxi institude of red soil which located in City of Jinxian, Jiangxi province. This study consisted of four treatments: (1) no fertilizer (CK); (2) nitrogen fertilizer (N); (3) nitrogen, phosphate and potassium fertilizer (NPK); (4) combined NPK fertilizer and organic fertilizer (NPKM). This study evaluate the effects of long-term different fertilization systems on soil organic carbon and total nitrogen content. Soil microbial community structure and abundance were identified using polymerase chain reaction following by denaturing gradient gel electrophoresis (PCR-DGGE) and real-time fluorescence quantitative PCR (qPCR), along with seven soil enzyme activities were measured with ultraviolet and fluorescence microplate, the main results are as follows:1.30 years combined application of chemical fertilizer and organic fertilizer increased soil organic carbon and total nitrogen content and increased 23% and 47% respectively as compared with no fertilizer, while chemical fertilizer showed no significant change.2. Fertilization treatments significantly increased soil chitinase activity. The NPK and NPKM treatments also enhanced the β-glucosidase and a-glucosidase activities as compared to N treatment. And compared with CK, soil cellulose and peroxidase activity only increased under NPKM treatment, while no changes of P-Xylosidase and acid phosphatase activities were occurred in different treatments.30 years combined application of chemical fertilizer and organic fertilizer significantly increased the normalized overall enzyme activity index as compared to control.3. The analysis of the abundance of soil bacteria, fungi, archaea, methanogens and methanotrophs showed that abundance of soil archaea were significantly lower than that of control, while other microbial abundance was not significant different in all treatments.4. Long-term combined application of chemical fertilizer and organic fertilizer increased soil bacterial diversity and changed the community structure of soil bacteria and fungi. Any significant effect of fertilization on soil fungal diversity was not found out. NPKM treatment stimulated two types of bacteria, belonging to Clostridium and Anaerolineaceae phyla.5. Long-term fertilization significantly decreased the diversity of soil archaea, but increased it of methanotrophs, and the diversity of methanotrophs was highest under NPKM treatment. Sequencing based phylogenetic tree analysis showed that, under NPKM treatment, one class of archaea that has not been identified disappeared, but two kinds of methanogenic archaea which were identified belonging to Methanomicrobiales and Methanosarcinales were stimulated as well as Type Ⅰ methanotrophs. |
PDF Full Text Request