Water-extractable soil carbon in relation to the belowground carbon cycle

• Published in: Biology and fertility of soils 1997-08, Vol.25 (2), p.196-201
• Main Authors: Jandl, R, Sollins, P
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Animal, plant and microbial ecology; biogeochemical cycles; Biological and medical sciences; biomass; carbon; carbon dioxide; Chemical, physicochemical, biochemical and biological properties; dissolved organic carbon; forest litter; forest soils; Forestry; Fundamental and applied biological sciences. Psychology; General forest ecology; Generalities. Production, biomass. Quality of wood and forest products. General forest ecology; microbial activity; Microbial ecology; Organic matter; Physics, chemistry, biochemistry and biology of agricultural and forest soils; respiration; seasonal variation; Soil; soil air; soil microorganisms; soil respiration; Soil science; substrates
• ISSN: 0178-2762; 1432-0789
• DOI: 10.1007/s003740050303

We investigated the role of water-extractable carbon (C-extr) as potential substrate for forest soil microorganisms by comparing belowground C fluxes at a plot with the forest floor removed (no-litter) and at a control plot. One-third lower soil respiration rates at the no-litter plot gave evidence that the forest floor was the source of considerable amounts of microbially degradable C. Laboratory incubation of C-extr, fractionated into neutral and acid moieties, showed that part of the C-extr was degraded rapidly, and that the high-molecular-weight acid fraction was much less degradable than the neutral C. To the extent that the degradable portion of the water-extractable C can be regenerated quickly, it may supply much of the substrate for heterotrophic soil respiration.