Foliar responses of tamarack and black spruce to drainage and fertilization of a minerotrophic peatland

Abstract

A drainage and fertilization experiment was established in 1989 in a tamarack (Larixlaricina (Du Roi) K. Koch) and black spruce (Piceamariana (Mill.) B.S.P.) mixed natural stand growing on a minerotrophic peatland. The drained site was ditched in fall 1987. Fertilization treatments of N–P–K at 0:0:0, 0:80:120, 200:80:120, and 400:80:120 kg•ha−1 (N as urea) were applied in late May 1989 Tamarack short-shoot needles and black spruce current-year needles, sampled on 31 August 1989 and 2 September 1990, were analysed for unit needle mass and N, P, and K. Drainage without fertilization increased foliar N, P, and K concentration of tamarack and black spruce, with larger responses occurring in tamarack. However, drainage decreased needle mass of unfertilized black spruce, although net assimilation rate increased, suggesting that an increased proportion of photosynthate was allocated to root development. Needle mass of tamarack was not affected in 1989 but was increased in 1990 by drainage, indicating different acclimation mechanisms to drainage by the two species. Responses in unit needle mass and foliar N and P concentration of both species to P–K alone, and (or) N–P–K fertilization, were higher on the drained than on the undrained site. Increased availability and uptake of N and P with a lowered water table were a likely consequence of increased near-surface soil temperature, improved soil water–soil aeration relations, and accelerated N and P mineralization and uptake rates. Foliar N, P, and K of tamarack were more responsive to fertilization than those of black spruce. N–P–K elevated foliar N concentrations of tamarack and black spruce and resulted in concomitant increases in needle mass, suggesting that N was limiting both species. Addition of P–K alone increased foliar P concentration and foliar mass of tamarack, indicating a P limitation to tamarack growth.

Effets du drainage sur la croissance et le statut nutritif d’un peuplement d’épinette noire de structure inéquienne : résultats de 10 ans

“…Il est en effet fréquent d'observer une augmentation des concentrations totales de N et P dans le sol après le drainage, alors que la teneur en K a tendance à rester stable ou à diminuer (Braekke 1987, Laiho et Laine 1994, Sundström et al 2000. L'amélioration de la disponibilité des nutriments peut également se refléter par des augmentations des concentrations foliaires de N, P et K, comme ce fut le cas pour l'épinette noire en Ontario (Stanek 1968, McLaren et Jeglum 1998 et en Alberta (Mugasha et al 1993). Dans la présente étude, les analyses foliaires n'ont toutefois montré aucun effet du drainage sur les teneurs en éléments nutritifs The Forestry Chronicle Downloaded from pubs.cif-ifc.org by 34.217.195.47 on 05/12/18…”

“…En abaissant le niveau de la nappe phréatique (Belleau et al 1992, Hillman 1992, le drainage augmente la température du sol (Lieffers et Rothwell 1987a, Prévost et al 1997 et permet une meilleure aération de la zone racinaire (Lieffers et Rothwell 1986, Silins et Rothwell 1999, Roy et al 2000, ce qui augmente l'absorption d'eau et d'éléments nutritifs (Lieffers et Macdonald 1990;Mugasha et al 1993Mugasha et al , 1999 et par le fait même, la croissance des arbres (Payandeh 1973, Wang et al 1985, Dang et Lieffers 1989, Sundström 1992. Les études tennoscandiennes font état de gains de croissance notables à la suite du drainage de peuplements établis (Heikurainen 1964, Heikurainen et Pakarinen 1982, Paavilainen et Päivänen 1995, mais les espèces et les conditions de sites diffèrent de ce qu'on retrouve dans la forêt boréale canadienne.…”

Current uptake of 15N-labeled ammonium and nitrate in flooded and non-flooded black spruce and tamarack seedlings

“…Nitrogen (N) is a limiting factor for trees growing in boreal peatlands (Bonan and Shugart, 1989;Mugasha et al, 1993). This has been attributed to low soil temperature and anaerobic soil conditions, which inhibit root activity and nutrient uptake while also resulting in slow rates of decomposition, N mineralization and nitrification, and activity of soil fungi and fauna (Campbell, 1980;Mugasha et al, 1993;Van Cleve and Alexander, 1981).…”

“…This has been attributed to low soil temperature and anaerobic soil conditions, which inhibit root activity and nutrient uptake while also resulting in slow rates of decomposition, N mineralization and nitrification, and activity of soil fungi and fauna (Campbell, 1980;Mugasha et al, 1993;Van Cleve and Alexander, 1981). Trees which grow in the boreal peatlands of western Canada, such as the evergreen black spruce (Picea mariana (Mill.)…”

The establishment of stem nutrient distribution zones of European larch and tamarack using principal component analysis

“…Likewise, since the concentration of all the nutrients is high in the apical zone, it can also be regarded as another storage location. The establishment of these storage zones is important since high foliar concentrations in larch have been related to efficient conservation, internal cycling or storage (Gower and Richards 1990;Mugasha et al 1993).…”