ISSN:
1573-5036
Keywords:
air pollution
;
ammonia
;
ammonium
;
15N
;
N concentration
;
needle
;
pine
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract Young saplings of Pinus sylvestris L. were exposed to gaseous NH3 at 53 or 105 μg m−3 for one year in open-top chambers. Saplings received 15N-labelled (NH4)2SO4 via the soil. To examine the importance of foliar N uptake, changes in the concentration of total and labelled N in the needles were followed. Increase in needle biomass and N concentration were found in trees exposed to NH3, confirming that atmospheric NH3 acted as a N fertilizer. NH3 had a greater and quicker effect than (NH4)2SO4: compared with the growth in ambient air, the N concentration in the needles exposed to NH3 had increased by 49% in four months, while the increase after highest N-fertilization (200 kg N ha−1 y−1) was only 8%. The small contribution of NH4 + fertilization to the total N concentration was not due to a deficient N uptake: the 15N concentration in the needles increased significantly with time. On the other hand, NH3 uptake in shoots may have a negative effect on the NH4 + root uptake. The relation between plant N and atmospheric NH3 concentration was non-linear and possible reasons for this observation are discussed. Fumigation with NH3 significantly decreased the ratios of K/N and P/N, showing that fumigation disrupted the nutrient balance.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00012996
