College of Life Science, Northeast Forestry University, Harbin, Heilongjiang, China.
Microbiologyopen. 2018 Apr;7(2):e00555. doi: 10.1002/mbo3.555. Epub 2018 Mar 13.
A better understanding of tree-based intercropping effects on soil physicochemical properties and bacterial community has a potential contribution to improvement of agroforestry productivity and sustainability. In this study, we investigated the effects of mulberry/alfalfa intercropping on soil physicochemical properties and soil bacterial community by MiSeq sequencing of bacterial 16S rRNA gene. The results showed a significant increase in the contents of available nitrogen, available phosphate, available potassium, and total carbon in the rhizosphere soil of the intercropped alfalfa. Sequencing results showed that intercropping improved bacterial richness and diversity of mulberry and alfalfa based on richness estimates and diversity indices. The relative abundances of Proteobacteria, Actinobacteria, and Firmicutes were significantly higher in intercropping mulberry than in monoculture mulberry; and the abundances of Proteobacteria, Bacteroidetes, and Gemmatimonadetes in the intercropping alfalfa were markedly higher than that in monoculture alfalfa. Bacterial taxa with soil nutrients cycling were enriched in the intercropping system. There were higher relative abundances of Bacillus (0.32%), Pseudomonas (0.14%), and Microbacterium (0.07%) in intercropping mulberry soil, and Bradyrhizobium (1.0%), Sphingomonas (0.56%), Pseudomonas (0.18%), Microbacterium (0.15%), Rhizobium (0.09%), Neorhizobium (0.08%), Rhodococcus (0.06%), and Burkholderia (0.04%) in intercropping alfalfa soil. Variance partition analysis showed that planting pattern contributed 26.7% of the total variation of bacterial community, and soil environmental factors explained approximately 56.5% of the total variation. This result indicated that the soil environmental factors were more important than the planting pattern in shaping the bacterial community in the field soil. Overall, mulberry/alfalfa intercropping changed soil bacterial community, which was related to changes in soil total carbon, available phosphate, and available potassium.
更好地理解基于树木的间作对土壤理化性质和细菌群落的影响，有助于提高农林复合系统的生产力和可持续性。本研究通过 MiSeq 测序细菌 16S rRNA 基因，研究了桑树/紫花苜蓿间作对根际土壤理化性质和土壤细菌群落的影响。结果表明，间作紫花苜蓿可显著增加根际土壤中有效氮、有效磷、有效钾和总碳的含量。测序结果表明，间作提高了桑树和紫花苜蓿的细菌丰富度和多样性，这可以从丰富度估计和多样性指数中看出。与单作桑树相比，间作桑树中变形菌门、放线菌门和厚壁菌门的相对丰度显著较高；间作紫花苜蓿中变形菌门、拟杆菌门和芽单胞菌门的丰度明显高于单作紫花苜蓿。参与土壤养分循环的细菌类群在间作系统中得到了富集。间作桑树土壤中芽孢杆菌（0.32%）、假单胞菌（0.14%）和微杆菌（0.07%）的相对丰度较高，而间作紫花苜蓿土壤中 Bradyrhizobium（1.0%）、Sphingomonas（0.56%）、假单胞菌（0.18%）、微杆菌（0.15%）、根瘤菌（0.09%）、新根瘤菌（0.08%）、 Rhodococcus（0.06%）和 Burkholderia（0.04%）的相对丰度较高。方差分解分析表明，种植模式对细菌群落的总变异贡献了 26.7%，土壤环境因素解释了总变异的约 56.5%。这一结果表明，在田间土壤中，土壤环境因素比种植模式对细菌群落的形成更为重要。总的来说，桑树/紫花苜蓿间作改变了土壤细菌群落，这与土壤总碳、有效磷和有效钾的变化有关。
