Effects of different leaf litters on the physicochemical properties and bacterial communities in Panax ginseng-growing soil

Abstract

Leaf litters play a very significant role in determining soil physicochemical properties and shaping soil microbial communities in forest ecosystems, but their impact on understory wild ginseng soil is unknown. In order to study that, different leaf litters from five tree species ((A) Acer mono. Maxim. var. mono; (B) Pinus densiflora Sieb. et Zucc.; (C) Juglans mandshurica Maxim.; (D) Tilia amurensis Rupr.; (E) Quercus mongolica Fisch. ex Ledeb) were added to Panax ginseng-growing soil. Our results indicated that the physicochemical properties of soil were significantly affected by all the leaf litter treatments. Soil total nitrogen, available NPK, and soil microbial biomass (carbon and nitrogen) significantly (P<0.05) increased across all treatments. In addition, we found that the soil bulk density and C/N ratio was lower following all treatments than in the control (no addition of leaf litter). Although the different kinds of added leaf litter had few effects on bacterial diversity and abundance, significant changes in the bacterial community composition could be identified in all soils; specifically, the relative abundance of Proteobacteria was higher in treatments than in the control. In addition, the bacterial communities of Bacteroidetes were fewer in treatments with coniferous leaf litter than those with broad leaf litter (P<0.05). Canonical discriminant analysis (CDA) ascertained that the shift of bacterial community composition and diversity were closely related with the changes in soil microbial biomass carbon and available nitrogen in all treatment soils. Our experiment results suggest that addition of leaf litter has a significant impact on soil bacterial community development, and it can lead to higher soil nutrients and soil microbial biomass, as well as a different bacterial community composition.