长期不同种植制度下植烟土壤细菌群落特征差异分析

Differences of soil bacterial community characteristics in tobacco field under different long-term cropping systems

为探讨长期不同烟草种植制度对土壤微生态环境的影响特征及各因子间的内在关系,在长期定位试验点分别收集撂荒地(AL)、烤烟连作(CC)、烤烟-玉米轮作(CR)的土壤样品,通过16SrRNA高通量测序技术,分析不同种植制度下土壤细菌群落和其他土壤环境因子特征及关系。结果表明,CC显著提高土壤中速效磷、速效钾含量及其过氧化氢酶活性(P<0.0(5),且分别较AL增加55.21mg/kg、108.06mg/kg和4.36μmol/g。不同种植制度下土壤细菌群落在门水平上组成相似,但在属水平上存在显著差异,其中以CC土壤中相对丰度最高的假节杆菌属(Pseudarthrobacter)和CR土壤中相对丰度最高的赭黄嗜盐囊属(Haliangium)差异最大,丰度分别高出AL 3.99%和0.90%;CC和CR提高了植烟土壤细菌群的丰度和多样性以及OTU数量,且以CR最为显著(P<0.0(5)。LEfSe差异分析表明,不同种植制度土壤的优势菌群组成上存在显著差异(P<0.0(5),其中CC、CR土壤中的主要优势细菌分别为假节杆菌属(Pseudarthrobacter)和赭黄嗜盐囊属(Haliangium)。RDA分析和Pearson相关性分析表明,优势菌群与差异微环境因子间存在较强的相关性,以土壤过氧化氢酶活性、速效钾含量对细菌群落分布影响最大,均与假节杆菌属(Pseudarthrobacter)的相对丰度呈显著正相关(P<0.0(5),与赭黄嗜盐囊属(Haliangium)的相对丰度呈显著负相关(P<0.0(5)。由此可见,不同种植制度会导致土壤微生态环境发生显著变化,长期连作会导致植烟土壤速效钾含量显著富集,土壤过氧化氢酶活性显著升高,有益细菌生长受到抑制,土壤细菌群落结构的稳定性受到破坏,进而影响土壤微生态环境的平衡。

In order to clarify the characteristics of soil bacterial communities in tobacco field and their correlations with other soil environmental factors under different long-term planting systems,soil samples from wasteland(AL),flue-cured tobacco continuous cropping(CC)and flue-cured tobacco-maize rotation(CR)were collected.The characteristics and relationships of soil bacterial communities and other soil environmental factors under different planting systems were analyzed by 16S rRNA high-throughput sequencing technology.The results showed that:CC significantly increased the content of available phosphorus,available potassium and catalase activities in soil(P<0.05),and increased by 55.21 mg/kg,108.06 mg/kg and 4.36μmol/g respectively compared with AL.The composition of soil bacterial communities in different planting systems was similar at the phylum level,but there were significant differences at the genus level.Among which,Pseudarthrobacter,which had the highest relative abundance in CC soil,and Haliangium which had the highest relative abundance in CR soil,displayed the largest differences.Their abundances were 3.99%and 0.90%higher than AL,respectively.CC and CR increased the abundance and diversity of bacterial biota and the number of OTUs in tobacco soil,with CR being the most significant(P<0.05).LEfSe difference analysis showed that there were significant differences in the composition of dominant flora in soils with different planting systems(P<0.05),among which the main dominant bacteria in CC and CR soils were Pseudarthrobacter and Haliangium.RDA analysis and Pearson correlation analysis showed that there was a strong correlation between dominant microbiota and different microenvironmental factors,and soil catalase activity and available potassium content had the greatest impact on the distribution of bacterial communities,which were significantly positively correlated with the relative abundance of Pseudarthrobacter and the relative abundance of Haliangium(P<0.05).In conclusion,different planting systems lead to significant changes in soil microecological environment,and long-term continuous cropping lead to significant enrichment of soil available potassium content,which significantly increase soil catalase activity,inhibit the growth of beneficial bacteria,reduce the stability of soil bacterial community structure,and then affect the balance of soil microecological environment.