Hedwall, Per-Ola
- Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences
Research article2015Peer reviewed
Hedwall, Per-Ola; Bergh, Johan; Nordin, Annika
Forest fertilization with nitrogen (N) has several benefits to society such as increased wood production and carbon sequestration. There are, however, concerns about N leakage, particularly following clear-cutting. The forest-floor vegetation may increase the N retention of forest ecosystems; however, very few studies have quantified the amount of vegetation required. We studied the relationship between vegetation cover and risk of N leakage, estimated by the amounts of ammonium-N and nitrate-N retained on ion-exchange capsules in the soil, during 4 years following the clear-cutting and harvesting of logging residues in a previously fertilized forest in southern Sweden. Previous fertilization increased the amount of nitrate-N captured on the capsules, whereas the amount of ammonium-N decreased. The vascular vegetation cover increased from almost zero to approximately 25% independent of fertilization. The amount of ammonium-N and nitrate-N retained on the capsules was already reduced by 50%-75% at 20% vegetation cover, and by 30%-40% cover, it approached zero, independent of the number of years since clear-cutting. The vegetation may impede tree-seedling establishment, implying a trade-off between seedling growth and N-retention capacity. However, our results indicate that maximum N retention may be achieved at a relatively low vegetation cover, which could be accomplished with less intrusive scarification methods than currently used.
nutrient leakage; nitrogen; forest fertilization; ground vegetation; immobilization
Canadian Journal of Forest Research
2015, Volume: 45, number: 1, pages: 130-134
Publisher: CANADIAN SCIENCE PUBLISHING, NRC RESEARCH PRESS
SLU Future Forests
Soil Science
Forest Science
DOI: https://doi.org/10.1139/cjfr-2014-0281
https://res.slu.se/id/publ/69354