The role of ectomycorrhization with Scleroderma sp. in promoting substrate nutrients mobilization under phosphorus-enriched compost amendment: A case study with Castanea henryi seedlings

Ecological forestry means continuous and sustainable management of production from the seedling to the adult stage. At present, ectomycorrhizal (ECM) fungi plays an important role in the nutrient management of seedling production seedling production in commercial forestry applications. Additionally, phosphorus-enriched compost (PEC) is considered as an environmentally cleaner soil amendment with a great potential in seedling production. However, little is known about the specific antagonistic or synergistic effects of these two sustainable practices on Castanea henryi seedling growth and nutrient uptake. An experiment was conducted to evaluate the effects of ECM inoculation (Scleroderma sp.) and three different application rates (0 %, 15 %, 35 % v:v) of phosphorus -enriched chestnut forest green waste compost (CFG; a typical form of PEC). Results indicated that CFG signifi-cantly increased the accumulation of most nutrients in plants but decreased the uptake of Cu and Zn. Without ECM inoculation, there was a significant positive correlation between soil rhizosphere bioavailable P content and aboveground seedling biomass (F = 111.570, p < 0.01). Inoculation of Scleroderma sp. significantly stimulated P mobilization in the soil rhizosphere of the low fertilization treatment (15 %) but had limited benefit in the non -fertilization (0 %) or high fertilization (35 %) treatments. The structural equation modeling indicated that the increase in activity of the rhizosphere soil acid phosphatase was the primary factor that increased soil P bioavailability and plant photosynthetic capacity in the inoculated treatments. Our results better explain the interaction of ECM on PEC sources of nutrients, and provide a low-cost and sustainable commercial propagation system underpinned by biologically regulated nutrient supply systems.