Comparison of the behavior of soluble organic and inorganic nutrients in forest soils

Modeling dissolved organic carbon in temperate forest soils: TRIPLEX-DOC model development and validation

“…This result is in general agreement with results from a number of studies that measured increased DOC export or concentrations (by 2-to 5-fold) in watershed soil water shortly after logging (Plamondon et al, 1982;Hinton et al, 1997;Startsev et al, 1998). This increase in DOC leaching may be attributable to the quantity of biomass (leaves, stem, and roots) left on the ground and soil, which is considered to be a primary source of increased DOC concentration and flux (Qualls, 2000;Piirainen et al, 2002). On the other hand, an increase in microbial activity could also be responsible for increased forest DOC concentrations and flux after forest harvesting.…”

“…Although our simulations do not provide a more detailed validation of the DOC submodel for different forest types, results indicate that DOC consumption and sorption/desorption-based soil submodels can reasonably capture general patterns in DOC concentration and flux rates related to soil depth, at least for temperate pine forests that we studied and where observed DOC flux data were available. Results also underscore the need for more detailed field experiment studies related to different types of forest ecosystems in major climatic regions and DOC sorption/desorption results from TRIPLEX-DOC are limited due to the model's use of an equilibrium distribution constant rather than using a time-dependent dynamical process (Qualls, 2000). This last point reflects the fact that TRIPLEX-DOC is in the early stage of model development as it pertains to DOC sorption/desorption and improvements could be made by incorporating more dynamic DOC sorption/desorption processes in more realistic ways.…”

Drained coastal peatlands: A potential nitrogen source to marine ecosystems under prolonged drought and heavy storm events—A microcosm experiment

“…3), which suggest drainage not only enhances the release of nitrate but also DON. Peat in the drained site contained higher inorganic nitrogen by increased nitrogen mineralization, which possibly promote microbial dissolution of organic compounds and hence increase the production of DON like amino acids (released during the hydrolysis of proteins) (Kalbitz and Geyer, 2002;Qualls, 2000). In our study, the ratio of DOC to DON was lower in the drained and natural sites than in the restored site, which suggest a preferential release of DON (Kalbitz and Geyer, 2002) from the natural and drained sites (Figs.…”

Experimental field estimation of organic nitrogen formation in tree canopies

“…However, the data show that the organic N deposition flux can increase or decrease as water moves through the canopy, depending on the availability of inorganic N. The implied (bio)chemical conversion has implications for the fate of TF nitrogen in the soil; processing of organic N in soil has been studied in more detail, taking as inputs to the soil surface the TF and SF that can be relatively simply measured below the forest canopy (Michalzik and Matzner, 1999, Möller et al, 2005, Qualls, 2000, Qualls and Haines, 1992. Attempts to estimate the complete budget of N inputs to forests for comparison with eventual drainage outputs, however, need to explicitly include not only the wet deposition of organic N (as recorded in Table 1), but the dry deposition of inorganic N (for which approximate estimates can be derived from measured air concentrations of gases and particles) and of organic N, for which no relevant data are yet available.…”