Changes in the soil biotic community are associated with variation in Illicium verum productivity

Purpose Soil biota plays a key role in nutrient decomposition and cycling. Plants have various strategies for interacting with soil biota. Soil microbial and soil nematode communities, soil physicochemical properties, as well as litter quality (total carbon, nitrogen and phosphorus) were assessed to investigate the changes in soil biotic communities associated with fruit production of Illicium verum forest. Methods Soil nutrients and soil biota existing in I. verum sites with low, intermediate, and high productivities were investigated. The study of soil biota consisted in determining the phospholipid fatty acid, fungi hyphae of arbuscular mycorrhiza, and soil nematodes. Results High productivity sites had higher soil phosphorus (P) content, which may produce more active P for biological consumption. High productivity sites also had a higher structure index, lower enrichment index, basal index, plant parasite index, fungivores/bacterivores ratio with respect to nematode community. High and intermediate productivity sites had lower spore density and longer hyphae length of arbuscular mycorrhizal fungi (AMF). Structural equation model demonstrated that nematodes reflected productivity indirectly and microbes had an overall slight negative effect on productivity. Conclusions Soil P plays an important role in increasing I. verum productivity. AMF symbiosis can contribute to P uptake, thus influences productivity positively. Bacterial dominant decomposition pathway indicates that soils in high productivity sites contain more available nutrient in comparison with low productivity sites. Lower nematode functional diversity and female-biased community demonstrate that soil food web complexity and the ability to provide a suitable environment for organisms are reduced in low productivity sites.