不同轮耕模式对黑土土壤微生物群落结构的影响

以吉林省公主岭市黑土3年的田间试验为研究对象,采用高通量测序方法,研究不同轮耕模式和秸秆还田对土壤微生物群落组成及其多样性的影响。结果表明,与秸秆离田处理(A)相比,秸秆连年深翻(D)、深翻/旋耕(C)和覆盖/覆盖/深翻(E)3个还田处理均显著提高亚表层(20～40 cm)土壤有机质和氮磷钾含量。对于微生物总量OTU分析表明,经过秸秆深翻处理亚表层土壤微生物总数均高于表层土壤,秸秆连年覆盖还田(B)处理则是表层(0～20 cm)土壤微生物总量高于亚表层土壤。经秸秆深翻处理亚表层土壤Chao1指数较高,Simpson指数较低,物种丰度明显提高;连年覆盖还田处理表层土壤物种Chao1指数和Shannon指数较高;秸秆覆盖还田可提高表层土壤物种丰度。C和D处理与A处理亚表层土壤组间物种多样性有显著差异,具体差异在分类学上的组成中有所体现,门水平上物种组成无差异,但属水平上亚表层土壤与表层土壤之间微生物组成不同。冗余分析显示,不同秸秆还田模式下土壤有机质及有效N、P养分变化是引起土壤微生物群落结构变化的重要环境因子。秸秆覆盖还田和秸秆深翻还田分别能够有效改善表层和亚表层土壤微生物群落结构和多样性。

Effects of Different Rotational Tillage Patterns on Soil Microbial Community Structure

The experiment of three years was carried out at Gongzhuling city, Jilin province. The effects of different tillage patterns and straw returning on soil microbial composition and diversity were studied by using high throughput sequencing technique. The results indicated that, compared with no straw returning treatment(A), continuous straw deep plough(D), plough/rotary/rotated tillage(C), and mulch/mulch/plough(E) treatments significantly increased soil organic matter, nitrogen, phosphorus and potassium content of subsurface layer. Straw plough treatment increased soil Chao1 index and lower Simpson index in subsurface soil, thus species richness was increased. Continuous straw mulching treatment increased soil Chao1 and Shannon index, thus species richness was increased. Deep ploughing/rotary tillage(C), continuous straw deep ploughing(D) have significant differences on microbial diversity compared with no straw returning treatment(A). Specific differences were found in taxology, no significant different was found on Phylum level, but significant differences of microbial diversity on genus level were exhibited between surface and sub-surface soil. Redundancy analysis indicated that soil organic carbon and available NP were the major environmental factors that causing the changes of soil microbial community. Straw mulching and straw deep ploughing could effectively change microbial community structure in surface and sub-surface soil, respectively.