覆盖对中小径级毛竹林地土壤细菌群落的影响

Effects of mulching on soil bacterial community in the small-to medium-diameter Phyllostachys edulis plantation

以中小径级覆盖毛竹林为研究对象,通过覆盖、轮休和长期覆盖模式试验,利用Illumina Miseq高通量测序技术和生物信息学分析不同经营方式的土壤细菌群落变化,探讨土壤菌群变异机制及其对覆盖毛竹林退化的影响。研究发现,在对照、覆盖、轮休和长期覆盖4种不同的经营方式下,土壤细菌种群多样性覆盖了26门69纲118目197属,其中酸杆菌在4类样地中占优势(30.85%~44.22%),其次是变形菌(8.23%~25.41%)、绿弯菌(2.48%~7.91%)、疣微菌(2.39%~6.82%)、AD3(1.05%~15.18%)、放线菌(3.99%~8.39%)和TM7(0.61%~6.68%)。与对照样地相比,其他3类样地土壤的全氮和有机碳含量均得到提高。覆盖、轮休和长期覆盖3类样地的p H值显著下降,且随着覆盖时间的延长,土壤酸化越明显。α-多样性分析和主坐标分析(principal co-ordinate analysis,PCo A)表明,覆盖经营对土壤细菌的种群多样性和群落结构产生了较大影响,覆盖提高了细菌数量、种类和丰度,其表面浅层翻耕处理使土壤不受机械干扰,短时间内形成0~20 cm厚的半腐熟有机物质层,为细菌繁殖提供能源,轮休样地的细菌数量、种类和丰度均为最高,而长期覆盖样地则均有所下降,Chao1指数甚至显著低于对照样地。本研究结果为中小径级低产毛竹定向培育和衰退毛竹林生态修复技术的研究提供了技术支撑和数据参考。

By high-throughput sequencing on Illumina Miseq platform and bioinformatics, changes of soil bacterial communities in a small-to medium-diameter Phyllostachys edulis plantation subjected to different soil management practices(mulching, alternate operation, and long-term mulching) were analyzed to investigate the mechanism of soil bacterial community variation and its effect on soil degradation of mulched P. edulis plantation.The results showed that soil subjected to four different soil management practices(CK, mulching, alternate operation, and long-term mulching) contained a wide diversity of bacterial communities covering 26 phyla, 69 classes, 118 orders, and 197 genera. Among them, Acidobacteria were the dominant in all four plots(30.85%-44.22%), followed by Proteobacteria(8.23%-25.41%), Chlorobacteria(2.48%-7.91%), Verrucomicrobia(2.39%-6.82%), AD3(1.05%-15.18%), Actinobacteria(3.99%-8.39%) and TM7(0.61%-6.68%). Soil total nitrogen and total organic carbon of all the three treatment sample plots were higher than those of the CK. The soil p H of the sample plots of mulching, alternate operation, and long-term mulching significantly decreased, and the soil became more acidic as the mulching period was prolonged. α-diversity and principal co-ordinate analysis showed that mulching had a greater impact on the diversity and structure of the soil bacterial community, and increased the number, species and abundance of bacteria. The shallow tillage of soil surface under the mulching prevented mechanical disturbance of the soil, thus forming a 0-20 cm thick layer of semi-decomposed organic matters within a short period of time to provide energy sources for bacterial reproduction. The alternate operation plot showed the greatest number, species and abundance of bacteria. However, the long-term mulching plot showed a decrease in the number, species and abundance of bacteria, as well as a significantly lower Chao1 index than the CK. This study provides technical support and data reference for research on orientation cultivation of low-yield bamboo and ecological restoration technology of bamboo forest.