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【Objective】 Soil microflora is an important indicator for characterizing the soil health. The objective of this study is to clarify the effects of different planting patterns on the structure and diversity of soil microbial communities i.e soil health in tropical areas, so as to provide theoretical basis and data support for optimizing the intercropping mode of Areca catechu L. and Pandanus amaryllifolius Roxb. 【Method】 Three planting modes: A. catechu L. Mono-cropping （DB）, Areca catechu L. intercropping P.amaryllifolius Roxb.（JZ） and P.amarylli folius Roxb. mono-cropping （DX） were set up under a field experiment to analysis the changes of microbial communities under different planting modes in this study. The relationships between the soil physical, nutrient content and other indicators and chemical characteristics and microbial communities were analyzed to explore the main factors driving the succession of soil microbial community in intercropping model. 【Result】 Intercropping mode did not affect fungal community, but significantly changed the structure and diversity of soil bacterial community. Intercropping mode significantly increased the richness and diversityindex of soil bacteria. The dominant phyla of bacterial in the soil samples among all treatments were Proteobacteria, Acid bacteria, Actinobacteria and Firmicutes with abundances of 22.59%, 19.60%, 16.66% and 16.11%, respectively. Compared with A. catechu L. mono-cropping, intercropping mode significantly increased the abundance of Acid bacteria and decreased the abundance of Firmicutes by 75.09% and 75.42%, respectively. The correlation analysis and RDA analysis indicated that the richness and diversity index of soil bacteria were mainly affected by the contents of soil available nitrogen, phosphorus, potassium and pH. Spearman’s rank correlation coefficients showed that the soil bacterial diversity was mainly affected by the soil nutrient content. 【Conclusion】 The richness and diversity index of soil bacterial community was inhibited by intercropping significantly by reducing soil available phosphorus, available potassium and available nitrogen content, and increasing soil p H. The soil nutrient content was decreased by intercropping, which significantly increased the species abundance of Acid bacteria, and decreased the species abundance of the Firmicutes. The intercropping mode could significantly improve the soil microflora of A. catechu L. mono-cropping. Intercropping will conducive to maintain soil health and sustainable development of related industries. [ABSTRACT FROM AUTHOR]

【Objective】 The present paper aimed to study the effects of Pandanus amaryllifolius Roxb. intercropping with Areca catechu L. on the structure and diversity of soil bacterial communities, to clarify the key environmental factors affecting soil bacterial community in the intercropping mode, so as to provide a theoretical basis for optimizing the betel nut intercropping mode and the development of tropical farmland economy. 【Method】 Through the method of field experiment, the experimental plots including A. catechu monocropping （control'), P. amaryllifolius monocropping （control） and P. amaryllifolius intercropping with A. catechu were established in Xinglong area to measure soil physical and chemical properties, nutrient content, soil bacterial abundance, and diversity to explore the effect of intercropping model on soil bacterial community structure and diversity. 【Result】 The results showed that the ACE index, Chao1 index and Shannon index of the bacterial community under the A. catechu intercropping P. amaryllifolius model were significantly reduced than control（P<0.05,the same as below）. In intercropping mode, pH, electrical conductivity, total phosphorus, and bulk density were the main environmental factors that affected the changes of soil bacterial communities. In the three planting modes, the dominant bacteria phyla of bacteria were Proteobacteria, Actin bacteria, Actin bacteria, and Chloroflexi. The relative abundance of Proteobacteria, Acid bacteria and Acidobacteria was decreased, and the relative abundance of Chloroflexi was increased. Among them, Acid bacteria was significantly positively correlated with soil bulk density; Chloroflexi was extremely significantly positively correlated with conductivity and organic matter （P<0.01,the same as below）, extremely significantly negatively correlated with total phosphorus, and significantly negatively correlated with total potassium. 【Conclusion】 P. amaryllifolius intercropping with A. catechu does not affect the total number of bacterial OTU, but significantly reduces the diversity index of soil bacterial community by reducing pH and increasing electrical conductivity. Intercropping mode reduces the contents of total phosphorus, total potassium and organic matter by increasing soil bulk density, while reducing the abundance of Proteobacteria, Actinomycetes and Acid bacteria, but increasing the abundance of Chloroflexi. It can be seen that although the betel nut intercropping system significantly reduces the content of soil nutrients, it can improve the abundance and diversity of in-situ soil bacterial flora of betel nut forest, which is of positive significance to maintain the soil health of betel nut forest and promote the development of related industries of betel nut and betel nut. [ABSTRACT FROM AUTHOR]