荔枝园间作柱花草对土壤理化性质和土壤细菌群落结构的影响

Effects of Intercropping Stylosanthes guianensis on Soil Physicochemical Properties and Bacterial Community Structure in a Litchi Orchard

探究荔枝园间作柱花草对土壤理化性质和土壤细菌群落结构的影响,为荔枝园间作柱花草提供理论依据。以荔枝园间作柱花草和荔枝单作2种模式的土壤样品进行土壤理化性质的测定,并进行细菌扩增子16S测序分析。结果显示:在荔枝园间作柱花草后,0~20 cm土层中,硝态氮含量显著提高47.52%,有效磷含量极显著提高141.53%,速效钾含量极显著降低125.59%;20~40 cm的土层深度,硝态氮含量极显著提高76.02%,有效磷含量显著提高48.52%,速效钾含量极显著降低188.57%。Alpha细菌多样性方面,在荔枝园间作柱花草后,0~20 cm土层和20~40 cm土层中,Chao1指数、AEC指数、Simpson指数和Shannon指数并无显著变化。在土壤细菌群落结构方面,土壤样品中主要的优势菌门均为Acidobacteriota、Proteobacteria、Firmicutes、Chloroflexi、Bacteroidota、Verrucomicrobiota、Actinobacteriota、Gemmatimonadota、Myxococcota,Crenarchaeota为0~20 cm土层深度下间作柱花草后土壤特有相对丰度大于1%菌门,Proteobacteria、Verrucomicrobiota、Gemmatimonadota的相对丰度在间作柱花草后的各土层深度均有提高;在属水平上,在0~20 cm土层,Candidatus_Nitrosotalea为间作柱花草后土壤特有相对丰度大于1%菌属,在0~40 cm土层,Nitrospira为间作柱花草后土壤特有相对丰度大于1%菌属;冗余分析结果表明,土壤细菌群落主要受有效磷、硝态氮和有机质的影响。综上所述,荔枝园间作柱花草会改善荔枝园土壤的理化性质和改变土壤细菌群落结构,对荔枝园土壤的环境条件起到一定的优化作用。

The study was aimed to investigate the effects of litchi orchard intercropping Stylosanthes guianensis on soil physicochemical properties and soil bacterial community structure,and to provide theoretical basis for litchi orchard intercropping S.guianensis.Soil samples from litchi orchard intercropped with S.guianensis and litchi monocropping modes were used to determine soil physicochemical properties and analyzed by bacterial amplicon sequencing.After intercropping S.guianensis in litchi orchard,in the soil layer depth of 0-20 cm,nitrate nitrogen content significantly increased by 47.52%,available phosphorus content highly significantly increased by 141.53% and available potassium content highly significantly reduced by 125.59%;in the soil layer depth of 20-40 cm,nitrate nitrogen content highly significantly increased by 76.02%,available phosphorus content highly significantly increased by 48.52%,and available potassium content highly significantly reduced by 188.57%.In terms of alpha bacterial diversity,there were no significant changes in Chao1 index,AEC index,Simpson index and Shannon index in 0-20 cm soil layer and 20-40 cm soil layer after intercropping S.guianensis in litchi orchard.In terms of soil bacterial community structure,the main dominant phyla in the soil samples were all Acidobacteriota,Proteobacteria,Firmicutes,Chloroflexi,Bacteroidota,Verrucomicrobiota,Actinobacteriota,Gemmatimonadota,Myxococcota,Crenarchaeota,and Crenarchaeota were soil-specific relative abundances greater than 1% of the phyla after intercropping S.guianensis at 0-20 cm soil depth;at the genus level,in the 0-20 cm soil layer,Candidatus_Nitrosotalea was the genus with soil-specific relative abundance greater than 1% after intercropping S.guianensis,and at the 0-40 cm soil level,Nitrospira was the genus with soil-specific relative abundance greater than 1% after intercropping S.guianensis,Proteobacteria,Verrucomicrobiota,and Gemmatimonadota increased at all soil depths after intercropping S.guianensis;the results of the redundancy analysis showed that the soil bacterial community was mainly affected by effective phosphorus,nitrate nitrogen,and organic matter.In summary,intercropping litchi orchard with S.guianensis would improve the physicochemical properties and change the structure of soil bacterial community in litchi orchard soil,and play a certain role in optimizing the environmental conditions of litchi orchard soil.