Effects of intercropping green manure on growth and rhizosphere soil microbial community structure of banana

【Objective】 This research studied the effects of intercropping green manure on the growth of banana and rhizosphere soil microbial community structure, to provide theoretical basis for the application and introduction of banana intercropping green manure model.【Method】 The experiment was conducted to study the aboveground part biomass, root part biomass and nutrient accumulation per plant of banana at bud stage which intercropped with four green manuresTrifolium pratense L., Arachis duranensis Krap.et Greg, Sphagneticola calendulacea(L.) Pruski, Crotalaria pallida Ait. at the stage after 1, 2, 3 months of transplanting. Analysis of α diversity, principal coordinate analysis(PCoA) and operational taxonomic units(OTUs) cluster analysis were conducted for soil microbial community in banana-green manure symbiotic area, with banana at 2 months intercropping with four green manures in the field. The horizontal fungus structure composition, relative abundance, species number and distribution of root exudates of phylum and genus levels were analyzed.【Result】 Plot experiment showed that, compared with banana monoculture in plot(CK1), the above-ground part biomass, root part biomass and nitrogen and potassium accumulation per plant of bananas intercropped with C. pallida after 2 months of transplanting significantly improved by 61.69%, 117.72%, 38.71% and 64.81% respectively(P<0.05, the same below). Those of bananas intercropped with C. pallida after 3 months of transplanting significantly increased by 47.97%, 67.79%, 34.53% and 52.04% respectively. Through field experiment, it was found that the community structure of bacteria and fungi in banana-green manure soil was obviously separated from monoculture banana in field (CK2). Compared with CK2, the ACE index and Shannon index of soil bacterial community increased by 5.53%-26.93% and 8.78%-14.52% in the symbiotic area, and ACE index decreased by 23.69%-32.21% and shannon index decreased by 11.70%-18.85% in the near-root area. Compared with CK2, the relative abundance of Actinobacteria increased by 17.97%-73.97% by planting green manure, and the relative abundance of Proteobacteria in root symbiotic area decreased by 12.32%-27.92%. The relative abundance of Bacillus was increased by 82.09%-260.14% and 0.85%-25.20% by intercropping with A. duranensis and S. calendulacea respectively. The relative abundance of Puccinia decreased by 94.48%-99.37% by intercropping with green manure. Intercropping green manure compared with CK2, the content of acids in near-root area was 7.06%-41.84% higher than that in root symbiotic area. The content of carbohydrates substances in the near-root area of intercropping with T. pratense and C. pallida was 88.11% and 64.19% higher than that in symbiotic area respectively.【Conclusion】 The effects of intercropping green manure on the banana growth of above-ground part, root part and nutrient accumulation are differentat diverse stage after banana transplanting.C. pallidais suitable for intercropping 2 months after banana transplanting.T. pratense, S. calendulacea and A. duranensisare suitable for intercropping 3 months after banana transplanting. Banana intercropping green manure can reduce the organic acid contents and the relative abundance of Proteobacteria, increase the relative abundance of Actinobacteria and Bacillusin the symbiotic area, promoting banana root growth and improving banana disease resistance.