Effects of p -Hydroxyphenylacetic Acid and p -Hydroxybenzoic Acid on Soil Bacterial and Fungal Communities

Soil phenolic acids mainly come from crop residue and root exudates, which are often reported as allelochemicals affecting crop growth and soil microbial community. Here, two phenolic acid compounds, p -hydroxyphenylacetic acid (HPA) and p -hydroxybenzoic acid (HBA) were amended to the soils and were incubated under room conditions, and the soil samples were collected from soybean and corn fields separately. The soil microbial community was determined by PCR-DGGE (polymerase chain reaction-denatured gradient gel electrophoresis) and clone methods. Microbial biomass carbon (MBC) was measured based on the fumigation–extraction method. The result revealed that HPA/HBA amendment significantly affected soil bacterial and fungal community structures. HPA/HBA enriched some distinct bacteria and fungi. The induced bacteria were mainly Gemmatimonas , Bacillus , and Acidobacteria, while the induced fungi were mainly Penicillium and Aspergillus . HPA amendment enhanced the more bacterial quantities of corn and soybean soils than HBA. The fungal diversity in corn and soybean soils treated with HBA was higher than that treated with HPA. It was speculated that the diversity of degrading HBA fungi was higher than that of degrading HPA. This study comprehensively analyzed the effects of phenolic acids on soil microbial community and increased the understanding of the monoculture barrier to agricultural production.