蚯蚓粪对槟榔根围土壤微生物多样性的影响

槟榔是海南省重要的支柱产业，而槟榔黄化严重导致了槟榔产量和品质下降，严重影响了海南省槟榔产业的发展。研究发现在槟榔根系施加蚯蚓粪对槟榔黄化具有较好的改善作用，但蚯蚓粪改善槟榔黄化的机制尚未清楚。因此，本研究选取海南万宁龙滚槟榔种植园为实验区，在根系设置3种处理，即蚯蚓粪组(TLG1)、蚯蚓粪和化肥（尿素）组(TLG2)、无任何添加的对照组(TLG3)，10个月后进行采样，利用Illumina Miseq高通量测序动态比较分析不同处理组土壤细菌多样性变化及微生物互作网络、揭示微生物多样性和土壤理化性质的相关性。结果表明，施加蚯蚓粪、蚯蚓粪和化肥的处理显著增强了槟榔根围土的微生物多样性，尤其是Acidothermus、Occallatibacter、Conexibacter在施加蚯蚓粪后显著增加（P<0.05）；而Candidatus Solibacter则明显降低（P<0.01），微生物互作网络分析结果表明，只施加蚯蚓粪的处理组中，所占丰度在前50的物种多出了Cyanobacteria门的一种菌（s_unclassified_g_norank_f_norank_o_Chloroplast），施加蚯蚓粪-化肥的处理组中多出了Patescibacteria门的一种菌（s_uncultured_bacterium_g_norank_f_LWQ8）。外源添加蚯蚓粪可显著增强土壤微生物的多样性和丰度，且显著增加了根系微生物互作网络的稳定性。此外，速效钾等理化因子对微生物类群拥有显著的影响，本研究结果对于进一步解析蚯蚓粪缓解槟榔黄化机制奠定了基础。

Effects of Earthworm Castings on the Microbial Diversity in the Rhizosphere of Arecanut Plants

Areca nut is an important pillar industry in Hainan Province, and arecanut yellow leaf disease occurring seriously in Hainan has led to the decline of areca nut yield and quality, and seriously affects the development of areca nut industry in Hainan Province. It was found that earthworm castings as vermicompost could reduce yellowing of arecanut leaves when applied to the rhisosphere, but its mechanism in reducing leaf yellowing resulting from arecanut leaf yellow disease was not clear. Therefore, an experiment was made at a Longgun arecanut plantation in Wanning County, Hainan Province by using earthworm castings as manure to observe the microbial diversity in the rhizosphere of arecanut plants in the arecanut plantation. Three treatments were arranged: earthworm castings (TLG1), earthworm castings + chemical fertilizer (urea) (TLG2) and the blank control (TLG3). After 10 months of treatment, samples were collected from the rhizosphere in the arecanut plantation to analyze the dynamic changes of soil bacterial diversity and microbial interaction network in different treatments by using Illumina Miseq high-throughput sequencing to reveal the correlation between microbial diversity and soil physical and chemical properties. The results showed that the treatments with the earthworm castings and the earthworm manure + urea increased significantly the microbial diversity in the rhizosphere of the aracanut plants, as compared with the control. The treatments of the earthworm castings and the earthworm castings + urea increased significantly Acidothermus, Occalatibacter and Conexibater at the genus level in the rhizosphere (P < 0.05), and reduced significantly Candidatus Solibacter (P < 0.05). The microbial interaction network analysis showed that a special bacteria (s_unclassified_G_norank_F_norank_O_Chloroplast), belonging to the phylum Cyanobacteria, and a species of bacteria (S_uncultured_ bacterium_ G_ norank_ F_ LWQ8), belonging to the phylum Patescibacteria, were found in the top 50 abundant species in the treatments with the earthworm castings and the earthworm castings + urea, respectively. This experiment showed that exogenous earthworm castings could significantly enhance the diversity and abundance of soil microorganisms in the rhizosphere of arecanut plants in the arecanut plantation, and significantly increase the stability of microbial interaction network in the rhizosphere. Moreover, the available potassium and other physical and chemical factors had a significant impact on microbial groups. The results of this experiment might provide some reference for further understanding of the mechanism of the earthworm castings in reducing leaf yellowing resulting from the yellow leaf disease.