Nitrogen-15 uptake by Pinus contorta seedlings in relation to phenological stage and season

• Published in: Scandinavian journal of forest research 2004-07, Vol.19 (4), p.329-338
• Main Authors: Amponsah, I.G, Lieffers, V.J, Comeau, P.G, Landhausser, S.M
• Format: Article
• Language: English
• Subjects: 15N recovery; fertilizer application; forest trees; isotopes; Labeled nitrogen; lodgepole pine; nitrogen; nutrient uptake; percentage NDFF; phenology; Pinus contorta var. latifolia; root growth; seasonal variation; seedlings; simulated seasons; tree nutrition
• ISSN: 0282-7581; 1651-1891
• DOI: 10.1080/02827580310019301

This study measured the amount of uptake of labeled nitrogen ( 15 N) of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm) seedlings, at three different phenological stages, in a growth chamber experiment. Thirty days after 15 N application, the amount of 15 N recovered in seedlings as a percentage of the total 15 N fertilizer applied was 4% in early spring, 43% in summer and 33% in autumn. The total 15 N recovered in the plant-pot system ranged from 80 to 96%, and is higher than reported in other studies. Total 15 N recovered from the pot compartment alone ranged from 48 to 95%, suggesting that substantial pools of N remain in the soil. Results suggest that low 15 N uptake in the spring was associated with limited development of new root as a result of low spring soil temperatures. The lack of unsuberized roots in spring could be a key factor decreasing the effectiveness of early spring fertilization in the boreal forest.