Litter decomposition in European coniferous and broadleaf forests under experimentally elevated acidity and nitrogen addition

authored by
Michal Růžek, Karolina Tahovská, Georg Guggenberger, Filip Oulehle
Abstract

Background: Atmospheric sulfur (S) and nitrogen (N) deposition has impacted many regions across the Northern Hemisphere inducing acidification and eutrophication of terrestrial ecosystems. However, acidification and eutrophication processes may differently impact litter decomposition and thus soil carbon (C) dynamics. Methods: We performed a field soil chemistry manipulation in two mountainous temperate forest stands (Picea abies and Fagus sylvatica) historically affected by acid (S and N) deposition. In each stand, four treatments were established: control, acid addition (H2SO4 – 50 kg S·ha− 1·year− 1), N addition (NH4NO3 – 50 kg N·ha− 1·year− 1) and their combination. In fourth year of manipulation, we established litter decomposition experiment. Litter bags of contrasting quality and origin (green tea, rooibos tea, spruce needles and beech leaves), in total 1536 samples, were buried below the organic layer and left to decompose up to 24 months. Retrieved samples were analysed for mass loss, C/N, and concentration of CuO oxidation lignin. Data were complemented by monitoring soil water pH and soil CO2 efflux. Results: Acid additions decreased soil water pH, soil respiration and suppressed decomposition of the high-quality litter (green tea) in both stands, whereas mass loss of remaining litter was reduced only in the spruce stand. Nitrogen treatments, when coupled with decreasing soil water pH, constrained needle decomposition in the naturally more acidic spruce stand. Conclusions: Our study demonstrates a suppressing effect of soil acidity on decomposition processes and soil C dynamics. The effect of N addition, as a nutrient, was insignificant, likely because of previous ecosystem adaptation to historical N loadings.

Organisation(s)
Institute of Soil Science
Section Soil Chemistry
External Organisation(s)
Charles University
Czech Geological Survey, Prague
University of South Bohemia
Global Change Research Institute – CzechGlobe
Type
Article
Journal
Plant and soil
Volume
463
Pages
471-485
No. of pages
15
ISSN
0032-079X
Publication date
06.2021
Publication status
Published
Peer reviewed
Yes
ASJC Scopus subject areas
Soil Science, Plant Science
Sustainable Development Goals
SDG 15 - Life on Land
Electronic version(s)
https://doi.org/10.1007/s11104-021-04926-9 (Access: Closed)