喀斯特山区不同种植方式下烟田土壤微生物特征分析

Characteristic of Soil Microorganism in Karst Mountain Areas Under Organic and Conventional Cultural Practices

为明确喀斯特山区烤烟由常规种植转为有机种植方式后烟田土壤微生物特征的变化,在贵州省金沙县以常规种植方式为对照,选择连续3年进行有机种植的烟田为试验对象,研究了两种种植方式下烟田土壤基本性质、细菌和真菌群落结构特征及其关键影响因素。结果表明,喀斯特山区烤烟种植方式由常规种植转换为有机种植后,土壤有机质、微生物生物量碳显著增加,而全氮、全钾、速效磷、速效钾等养分含量（质量分数）显著降低（p〈0.05）;两种种植方式下,土壤微生物丰富度和多样性均以细菌高于真菌,土壤细菌和真菌多样性以及在＂门＂分类上的群落结构差异不大,细菌以变形菌门、放线菌门、酸杆菌门占优势（54.2%-62.0%）,真菌以子囊菌门占绝对优势（74.4%）;常规种植转为有机种植方式后,烟田土壤有益微生物类群数量增加。喀斯特山区烟田土壤微生物群落结构主要受土壤有机质、养分和容重的影响。

To investigate the changes of soil microbial characteristics in Karst mountain areas caused by the transformation from conventional cultivation into organic cultivation, an experiment was carried out in tobacco fields on which organic cultivation had been conducted for three consecutive years in Jinsha County, Guizhou Province by taking conventional cultivation as the control. The basic soil properties, bacterial and fungal community structure and key influencing factors were studied. The results showed that： comparing with conventional cultivation, the contents of soil organic matter and microbial biomass carbon significantly increased, the contents of soil nutrients （total nitrogen, total potassium, available phosphorus, available potassium, etc） significantly decreased （p〈0.05）, and the amount of beneficial microorganism groups increased as a result of organic cultivation. The richness and diversity of bacteria were higher than those of fungi were common to both cultural practices. The diversities and microbial communities at phylum level were not obviously different between conventional and organic cultural practices. Bacterial communities dominated by Proteobacteria, Actinobacteria and Acidobacteria （accounted for 54.2%-62.0% ）, and fungal communities dominated by Ascomycota （accounted for 74.4% ）. The microbial communities in Karst mountain areas were mainly influenced by the organic matter, nutrient and bulk density in soil.