Nitrogen leaching following clear-cutting and soil scarification at a Scots pine site – A modelling study of a fertilization experiment
2017 (English)In: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 385, 281-294 p.Article in journal (Refereed) Published
Boreal forest stands fertilized with nitrogen (N) might be susceptible to elevated N leaching following clear-cutting, with consequences for water quality and soil acidification. Here, we studied a forest fertilization experiment with N, 165 Hagfors, in Sweden during the first six years (2006–2011) following clear-cutting. The N fertilization treatments were 0 kg ha−1 (0 N) and 450 kg ha−1 of N (450 N), supplied during 1981–1992 to a Scots pine (Pinus sylvestris L.) stand: the stand was harvested in March 2006. Following clear-cutting, disc trenching was performed and furrows (F), ridges (R) and areas in-between two furrows (IB) were created. We calculated the N leaching fluxes and ecosystem N budget during 2006–2011 as affected by previous N fertilization, disc trenching and interactions thereof, at Hagfors by the use of a process-based biogeophysical ecosystem model (CoupModel). The model was calibrated against measurements of soil water and temperature dynamics and previously reported measurements of N in soil solution, soil organic matter and vegetation biomass. Criteria for acceptance of model estimates were based on the range enclosed by the 95% confidence intervals of the mean of the field data used in calibration sampled at low frequency (1–2 occasions) and a combination of the mean error and the coefficient of the determination for variables sampled at a higher frequency (28–1921 occasions). The accepted model estimates of the mean annual leaching rates of N were 3.1 (range 1.4–22.7) and 2.4 (range 0.8–7.0) kg ha−1 of N year−1 in the treatments 0 N and 450 N, respectively, without disc trenching. Disc trenching increased N leaching during the regeneration phase, more so in the 450 N treatment (mean 6.1, range 1.9–16.7 kg ha−1 of N year−1) than in the 0 N treatment (mean 4.6, range 1.9–12.9 kg ha−1 of N year−1). Overall, differences in the posterior model parameter estimates between N treatments and disc trenched treatments F, R and IB were related to the soil physical component: the differences resulted in enhanced drainage in the disc trenched treatments. We conclude that vegetation biomass N accumulation controlled soil water N leaching, and disc trenching increased N leaching from the previously N fertilized plots at Hagfors by its effects on water drainage flow and vegetation N uptake. This finding warrants more research since N fertilization followed by soil scarification in boreal forests is a practice which may increase in the future.
Place, publisher, year, edition, pages
Elsevier, 2017. Vol. 385, 281-294 p.
Disc trenching, Ecosystem modelling, Forest regeneration, Nitrogen cycling, Nitrogen leaching, Budget control, Calibration, Compressive strength, Ecology, Ecosystems, Leaching, Nitrogen, Nitrogen fertilizers, Reforestation, Soil moisture, Soils, Trenching, Vegetation, Water quality, Fertilization experiment, Forest fertilization, Soil organic matters, Temperature dynamics, Forestry, Pinus sylvestris
IdentifiersURN: urn:nbn:se:kth:diva-201956DOI: 10.1016/j.foreco.2016.11.006ScopusID: 2-s2.0-85007369653OAI: oai:DiVA.org:kth-201956DiVA: diva2:1078419
QC 201703032017-03-032017-03-032017-03-03Bibliographically approved