Increased Saprotrophic Activity and Phosphate Leaching Following Forest Soil Decomposition without Root Access

• Published in: Forests 2024-08, Vol.15 (8), p.1378
• Main Authors: Tahovská, Karolina, Choma, Michal, Čapek, Petr, Kaštovská, Eva, Kaňa, Jiří, Kopáček, Jiří
• Format: Article
• Language: English
• Subjects: Acid phosphatase; Acidic soils; Bacterial leaching; Biodegradation; Biomass; Boxes; Carbon; Coniferous forests; Decomposition; Decomposition reactions; Dieback; disturbance; Ectomycorrhizas; Environmental aspects; Enzymes; Experiments; Forest management; Forest soils; Fungi; Immobilization; In situ leaching; Ion exchange; Ion exchange resins; ion-exchange resin; Leaching; Microbiomes; Microorganisms; Nitrogen; Nitrogen cycle; Nutrient uptake; Organic matter; Organic phosphorus; Organic soils; Organometallic compounds; Phosphatase; Phosphates; Phosphorus; Physiological aspects; Roots (Botany); saprotrophs; Soil microorganisms; soil phosphorus; Soil water; spruce forest; Trees
• ISSN: 1999-4907; 1999-4907
• DOI: 10.3390/f15081378

By incubating the soil without living roots in situ at two spruce forest sites, we simulated the effects of tree dieback and interrupted mycorrhizal associations following forest disturbance on the soil microbiome and phosphorus leaching. We observed the retreat of ectomycorrhizal fungi and increased proportion of saprotrophs without changes in community richness and the Shannon diversity index. This was accompanied by a pronounced decomposition of organic matter, associated with an increased activity of carbon-mining hydrolases and acid phosphatase. The nonexistent phosphorus uptake and immobilization by ectomycorrhizal associations led to its substantial increase in the soil, in the labile fractions, such as microbial biomass and water-soluble reactive phosphorus, but also in the fraction bound to organometallics (extractable by oxalate), and caused considerable phosphate leaching, as estimated using ion-exchange resin traps. The results show that the retreat of the root-specific environment, characterized by the input of available carbon and effective nutrient uptake and by the specific microbiome, has profound effects on phosphorus dynamics and loss. Furthermore, we suggest that ectomycorrhiza plays an equally important role in controlling phosphorus-mining from organic matter and subsequent immobilization and/or leaching from soils concurrently to its known role in nitrogen cycling and immobilization in spruce forests.