International Journal of Plant & Soil Science, ISSN: 2320-7035,Vol.: 2, Issue.: 2 (July-December)
Role of Soil Nitrogen for the Conifers of the Boreal Forest: A Critical Review
Carlo Lupi1*, Hubert Morin1, Annie Deslauriers1, Sergio Rossi1, and Daniel Houle2,3 1555, University Blvd, Chicoutimi (QC), G7H 2B1, Canada, University of Quebec at Chicoutimi (UQAC), Fundamental Sciences Department, Canada.
2Forestry Research Direction, Quebec Forest, Ministry of Natural Resources and Fauna of Quebec (QC), G1P 3W8, Canada.
3Consortium on regional climatology and adaptation to climate changes (Ouranos), Montreal (QC), H3A 1B9, Canada.
Carlo Lupi1*, Hubert Morin1, Annie Deslauriers1, Sergio Rossi1, and Daniel Houle2,3
1555, University Blvd, Chicoutimi (QC), G7H 2B1, Canada, University of Quebec at Chicoutimi (UQAC), Fundamental Sciences Department, Canada.
(1) Sławomir Borek, Faculty of Biology, Department of Plant Physiology, Adam Mickiewicz University, Poland.
(2) Knut Kielland, University of Alaska, USA.
Complete Peer review History: http://www.sciencedomain.org/review-history/1747
Nitrogen is considered the most important element in plant nutrition and growth. However its role and availability for boreal forest conifers is still debated. Boreal conifers have adapted strategies to cope with the reduced availability of N. ECM fungi, associated with boreal conifer roots, increase soil exploration and N nutrition, especially where organic N predominates. Conifers usually take up ammonium at levels comparable to simple organic N, which probably grows in importance as organic matter accumulates with stand age, while estimates of nitrate uptake are generally lower. Conifers, especially slow growing species, may rely on internal N cycling to sustain the development of new tissues in spring. N increases photosynthesis and leaf area and thus increases growth and wood formation, leading to wider radial rings mostly because of increased earlywood production. N-depositions and disturbances (e.g. fire and harvest) may alter the soil N-cycle and affect boreal forest growth. N depositions are considered responsible for the increase in boreal forest growth during the last century. Intensive harvest and high N-depositions may shift limitation from N to another element (e.g. P, K, and B). Climate change should affect the N cycle through complex mechanisms, including changes in the fire return interval, direct effects of warmer soils on N mineralization and stimulating plant growth modifying the balance between N stored in soils and in the living and dead (e.g. wood) biomass. Future research should try to improve our understanding of the possible outcomes of changes in disturbance regimes, N-depositions and climate, including the role of N fixation by mosses, canopy N uptake and the responses of conifers in relation to changes in microbial (symbiotic and not) communities.
Ammonium; boreal conifers; growth; N limitation; nitrate; N uptake.
Full Article - PDF Page 155-189
DOI : 10.9734/IJPSS/2013/4233Review History Comments