Fungal communities in barren forest soil after amendment with different wood substrates and their possible effects on trees’, pathogens, insects and nematodes

Abstract

AbstractScots pine sawdust, composted bark or coarse, post-harvest woody debris from conifers had been spread over the surface of barren forest soil before planting with Scots pine. The effects of the Scots pine sawdust, composted bark or coarse, post-harvest woody debris from conifers on the abundance and diversity of culturable fungi were investigated. The amendments were aimed at increasing the soil suppressiveness toArmillariaandHeterobasidion.The classical soil-dilution method was chosen for qualitative and quantitative analyses of fungal communities in soils because of its proven reliability and consistency. The soil was inhabited by saprotrophic fungi from Ascomycota and Zygomycota, including species known to be potential antagonists ofArmillariaorH. annosum(i.e.Clonostachys + Trichodermaspp.,Penicillium commune, P. daleae,P. janczewskii) or stimulants ofArmillaria(i.e.Pseudogymnoascus roseus,Trichocladium opacum). Eleven years after treatment, the abundance and diversity of fungi, the abundance ofP. commune, and locally the abundance ofP. janczewskiiincreased, whileClonostachys + Trichodermaspp., and locally,P. daleaeandT. opacumdecreased. Amending the barren soil with organic matter does not guarantee effective, long-term suppressiveness of the sandy loam soil toArmillariaandHeterobasidion.Increased abundance of entomopathogenic and nematophagous species, 11 years after treatment, does suggest the long-term possibility of insect or nematode control in soil.