Effects of fertilization on seasonal patterns of foliar mass and nutrientsof tamarack and black spruce on undrained and drained minerotrophic peatland sites
Ag. Mugasha et al., Effects of fertilization on seasonal patterns of foliar mass and nutrientsof tamarack and black spruce on undrained and drained minerotrophic peatland sites, FOREST ECOL, 116(1-3), 1999, pp. 13-31
We investigated seasonal patterns of needle mass and foliar N, P and K of t
amarack (Larix laricina (Du Roi) K. Koch.) and black spruce (Picea mariana
(Mill.) B.S.P.) as affected by fertilization of undrained and drained miner
otrophic peatland sites. The drained site was ditched in fall 1987. Four N-
P-K fertilization treatments, i.e. 0-0-0, 0-80-120, 200-80-120, and 400-80-
120 kg ha(-1), replicated three times on each site were applied at the end
of May 1989. Short-shoot needle of tamarack and current and one-year needle
s of black spruce were sampled bi-weekly from 12 June to 15 October, 1989.
Drainage and fertilization modified the foliar phenology of tamarack, Budbr
eak and senescence of needles were delayed on the drained site. N-fertiliza
tion delayed senescence of tamarack needles for two weeks on the undrained
site. Needle mass of short-shoots of tamarack and current needles of black
spruce increased during needle expansion on both sites. During needle matur
ation, current needle mass of black spruce increased on both sites in all t
reatments with greater increase in N-fertilized plots. N-fertilization incr
eased foliar N of both species on both sires with greater increase on the d
rained but decreased foliar P and K throughout the season, PK-fertilization
increased P and K contents and concentrations of tamarack on the drained s
ite and of current and one-year-old needles of black spruce. For tamarack,
drainage without fertilization increased rates of efflux (negative value) o
f foliar N, P and K. N-fertilization increased influx of N and P during nee
dle elongation and expansion, i.e. phases 1 and 2, respectively. During nee
dle senescence, efflux of N and K on the drained site were greater in N-fer
tilized plots than in N0PK plots. For black spruce, drained without fertili
zation resulted in an influx of P and K and efflux of N. Additionally, N-fe
rtilization increased influx of P in the undrained site during needle expan
sion. (C) 1999 Published by Elsevier Science B.V. All rights reserved.