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Introduction: Microorganisms play a critical role in soil biogeochemical cycles, but it is still debated whether they influence soil biogeochemical processes through community composition and diversity or not. This study aims to investigate variation in bacterial community structure across different soils and its correlation to soil multifunctionality. Soil samples were collected from five typical farmland zones along distinct climatic gradients in China. Methods: The high-throughput sequencing (Illumina MiSeq) of 16S rRNA genes was employed to analyze bacterial community composition in each soil sample. Multivariate analysis was used to determine the difference in soil properties, microbial community and functioning, and their interactions. Results: Cluster and discrimination analysis indicated that bacterial community composition was similar in five tested soil samples, but bacterial richness combined with soil enzyme activities and potential nitrification rate (PNR) contributed most to the differentiations of soil samples. Mantel test analysis revealed that bacterial community composition and richness were more significantly shaped by soil nutrient conditions and edaphic variables than bacterial diversity. As for soil multifunctionality, soil microbial community level physiological profiles were little affected by abiotic and biotic factors, while soil enzymes and PNR were also significantly related to bacterial community composition and richness, in addition to soil N and P availability. Conclusion: Cumulatively, soil enzymes' activities and PNR were greatly dependent on bacterial community composition and richness not diversity, which in turn were greatly modified by soil N and P availability. Therefore, in the future it should be considered for the role of fertilization in the modification of bacterial community and the consequent control of nutrient cycling in soil.
RESUMO
OBJECTIVE: To analyze the epidemiological characteristics of malaria in Leshan City, so as to provide the evidence for formulating the strategy and measures for consolidating the achievements of malaria elimination. METHODS: The data of epidemiological characteristics of malaria in Leshan City from 1950 to 2015 were collected and analyzed with the descriptive epidemiology method. RESULTS: There were four larger scale epidemics of malaria in Leshan City from 1950 to 2015. The order of malaria in infectious diseases dropped from the first to the twentieth. The peak season for malaria epidemics ceased. The Plasmodium species, patient age, occupation and sex distribution of malaria were different in the different periods. In November 2016, the whole city achieved the national standard for malaria elimination. CONCLUSIONS: After years of prevention and control, the epidemiological characteristics of malaria have changed significantly in Leshan City, and the effect of anti-malarial measures is significant. In the future, we should strengthen the monitoring, and prevention and control of imported malaria.
