元江稻作梯田旱作化对土壤肥力和微生物群落结构的影响OA

To explore the effects of dry tillage of rice paddy fields on the soil fertility and microbial community structure,providing a reference for the utilization of dry tillage in rice terraces and the restoration and protection of terraced ecosystems,the soil in the typical paddy fields before and after dry tillage in Yuanjiang Hani,Yi and Dai Autonomous county,Yuxi city,Yunnan province were sampled and subjected to high throughput sequencing.The soil microbial community structure of four different farming environments(rice fields planting rice landrace Mazhagu in consecutive years,rice fields planting rice landrace Honghezigu in consecutive years,the field planting corn which was transformed to dryland from paddy fields 5 years ago,the field planting corn which was transformed to dryland from paddy fields 10 years ago)was analyzed and its relationship with the soil nutrient content was further explored.Results showed that the soil pH,organic matter,organic carbon,total nitrogen,total phosphorus,available phosphorus,available potassium,and alkali-hydrolyzed nitrogen content increased with the increase of dry tillage years.The diversity and abundance of soil microorganisms in the early stage of dry tillage decreased significantly due to the decrease of soil moisture,but they increased slightly with the extension of dry-cropping years.The dominant fungal phyla of the four soil samples were Ascomycetes and Basidiomycetes,among which the abundance of Ascomycetes was relatively higher in dryland and the abundance of Basidiomycetes was relative higher in paddy fields.The dominant bacterial phyla were all Proteobacteria.The analysis of the response of soil microorganisms to soil nutrient factors showed that the soil fungal community was more closely related to soil nutrient content compared with the soil bacteria.The study showed that soil nutrient status and microbial community structure in paddy fields before and after dry tillage were significantly different,and long-term paddy field management measures led to the formation of a unique microbial community structure in paddy fields,and the diversity and abundance of soil microorganisms in the early stage of dry tillage would be significantly reduced due to the decrease of soil moisture.