Alien red oak affects soil organic matter cycling and nutrient availability in low-fertility well-developed soils

• Published in: Plant and soil 2015-10, Vol.395 (1-2), p.215-229
• Main Authors: Bonifacio, Eleonora, Petrillo, Marta, Petrella, Fabio, Tambone, Fulvia, Celi, Luisella
• Format: Article
• Language: English
• Subjects: biogeochemical cycles; Biomedical and Life Sciences; calcium; carbon; Charcoal; Decomposing organic matter; Decomposition; Ecological function; Ecology; Ecosystems; Environmental aspects; Fertility; Forest soils; Humus; Introduced species; Invasive species; Life Sciences; Litter; nuclear magnetic resonance spectroscopy; Nutrient availability; Nutrient cycles; Nutrients; organic horizons; organic matter; Organic phosphorus; oxidation; Phosphorus; Plant introduction; Plant Physiology; Plant Sciences; Plant-soil relationships; Quercus robur; Red oak; Regular Article; Respiration; sodium hypochlorite; Soil organic matter; soil respiration; Soil Science & Conservation; Soils; stable isotopes; tannins; Trees
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-015-2555-9

BACKGROUND AND AIMS: Invasive alien species can dramatically change the litter and organic matter decomposition rate, nutrient cycling and availability, thus threatening the ecosystem functionality. We assessed the effect of red oak (QR) introduction on low fertility well-developed soils, originally covered by Quercus robur L. (QC). METHODS: We determined litter and soil organic matter composition and decomposition rate by combining morphological features with ¹³C NMR spectroscopy, NaClO oxidation and soil respiration. Total and available nutrients were also determined. RESULTS: The sites showed different humus forms: Dysmull-Hemimoder in QC and Mor in QR. The Oi horizons had a similar composition, but the higher presence of tannins and alkyl C/O − alkyl C and aryl C/O − alkyl C ratios in QR indicated that litter was less degradable. This was confirmed by soil respiration tests, with a higher preservation of the NaClO resistant fraction along the profile, mainly due to selective accumulation of alkyl components. This was accompanied by high retention of phosphorus in the organic horizons and drastic reduction of both total and available P in the mineral horizons. Calcium was strongly affected too. CONCLUSIONS: In these well-developed soils red oak changed organic matter dynamics, reduced P availability and cation biocycling, leading the ecosystem functionality towards a no-return threshold.