Resource control on the production of dissolved organic carbon and nitrogen in a deciduous forest floor

Ji Hyung Park, Karsten Kalbitz, Egbert Matzner

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147 Scopus citations


The forest floor in temperate forests has become recognized for its importance in the retention of elevated inputs of dissolved inorganic nitrogen (DIN) and as a source of dissolved organic matter (DOM). A laboratory leaching experiment was conducted over the period of 98 d to examine the origin of dissolved organic carbon (DOC) and nitrogen (DON) in a deciduous forest floor, and the effect of resource availability and microbial activity on the production mechanisms involved. The experiment was composed of different types of treatments: exclusion of specific forest floor layers (no Oi, no Oe) and addition of carbon sources (glucose, cellulose, leaf, wood) and NH4NO3 (nitrogen). The cumulative amount of CO2 evolution was positively related to the availability of C sources at each treatment: glucose > leaf = wood = cellulose > control = no Oe = nitrogen > no Oi. DOC release was related to the amount of C sources but showed no clear correlation with CO2 evolution. An increase in C availability generally led to a reduction in the release of DON as well as DIN. In contrast, the amendment of NH4NO3 reduced the cumulative DOC release but enhanced the release of both DON and DIN. Fresh leaf litter was a more important DOC source than labile substrates (glucose and cellulose) as well as more stable substrates (forest floor materials and wood). Among forest floor layers, more humified horizons (Oe and Oa) were the primary source of DIN and made a similar contribution to DOM release as the Oi layer. The changes in DOM composition detected by a humification index of the leachates, in combination with a shift in the final microbial biomass C, suggested that DOM released from the soluble pools of added litter or the Oi layer contained a substantial amount of microbially processed organic matter. Our study demonstrated the importance of C availability in regulating microbial activity and immobilization of dissolved N in an N-enriched forest floor. However, the discrepancy between substrate lability and DOC production, in combination with a rapid microbial processing of DOC released from labile C pools, illustrated the complicated nature of microbial production and consumption of DOC in the forest floor.

Original languageEnglish
Pages (from-to)813-822
Number of pages10
JournalSoil Biology and Biochemistry
Issue number6
StatePublished - 2002

Bibliographical note

Funding Information:
We thank Stefan Andersson for many helpful comments on the design of incubation columns and CO 2 measurement technique, Uwe Hell and the members of the Central Analytic Department of the BITÖK for technical assistance, and Katherine Kim for correcting the English text. This research was supported by the German Ministry of Education, Science, Research and Technology. Financial support was provided to JHP by the German Academic Exchange Service (DAAD).


  • C and N availability
  • Dissolved inorganic nitrogen
  • Dissolved organic carbon
  • Dissolved organic matter
  • Dissolved organic nitrogen
  • Forest floor
  • Soil microbial activity


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