Intercropping Pinto Peanut in Litchi Orchard Effectively Improved Soil Available Potassium Content, Optimized Soil Bacterial Community Structure, and Advanced Bacterial Community Diversity

Ya Zhao; Caibin Yan; Fuchu Hu; Zhiwen Luo; Shiqing Zhang; Min Xiao; Zhe Chen; Hongyan Fan

doi:10.3389/fmicb.2022.868312

Intercropping Pinto Peanut in Litchi Orchard Effectively Improved Soil Available Potassium Content, Optimized Soil Bacterial Community Structure, and Advanced Bacterial Community Diversity

Front Microbiol. 2022 May 12:13:868312. doi: 10.3389/fmicb.2022.868312. eCollection 2022.

Authors

Ya Zhao¹, Caibin Yan¹, Fuchu Hu¹, Zhiwen Luo¹, Shiqing Zhang¹, Min Xiao¹, Zhe Chen¹, Hongyan Fan¹

Affiliation

¹ Key Laboratory of Tropical Fruit Tree Biology of Hainan Province, Ministry of Agriculture and Rural Affairs/Haikou Tropical Fruit Tree Scientific Observation and Experimental Station, Institute of Tropical Fruit Trees, Hainan Academy of Agricultural Sciences, Haikou, China.

Abstract

Intercropping is widely used in agricultural production due to its capability of raising land productivity and providing an opportunity to achieve sustainable intensification of agriculture. In this study, soil samples from 10 to 20 cm depth of intercropping Pinto peanut in litchi orchard and litchi monoculture mode were established to determine soil attributes, enzyme activities, as well as the effect on soil bacterial diversity. On this basis, 16S rRNA V4-V5 region of soil bacterial communities in litchi/Pinto peanut intercropping (LP) mode and litchi monoculture mode (CK) was detected by the Illumina MiSeq sequencing platform. The results showed that the content of available potassium (AK) in LP was significantly higher than that in CK by 138.9%, and the content of available nitrogen (AN) in LP was significantly lower than that in CK by 19.6%. The soil enzyme activities were higher in LP as a whole, especially sucrase (SC) and acid protease (PT) were significantly higher by 154.4 and 76.5%, respectively. The absolute abundance and alpha diversity of soil microbiota were significantly higher in the intercropping group. Most importantly, endemic species with a significant difference in LP was higher by ~60 times compared to CK treatment. In the aspect of soil bacterial community structure, the dominant phyla of the two groups were Acidobacteria, Proteobacteria, Chloroflexi, and Actinobacteria. At the genus level, the absolute abundance of Flavobacterium and Nitrososphaera was significantly higher by 79.20 and 72.93%, respectively, while that of Candidatus_Koribacter was significantly lower with an amplitude of 62.24% in LP than in CK. Furthermore, the redundancy analysis (RDA) suggested that AK, which was highly associated with the dominant genera and phyla, is the vitally dominating environmental factors in LP groups, while in CK groups, it is AN and pH. In addition, PICRUSt2 analysis indicated that intercropping improved the metabolic activity of bacteria which can be correlated to the resistance of litchi root systems to soil-borne diseases. Overall, this study is expected to provide a theoretical basis and technical support for the healthy intercropping cultivation of litchi.

Keywords: intercropping Pinto peanut in litchi; soil bacterial community structure; soil bacterial diversity; soil enzyme activity; soil properties.