Soil solution and sugar maple response to NH4 NO3 additions in a base-poor northern hardwood forest of Québec, Canada

Published in Environment Monitoring and Assessment 155: 177-190

Nitrogen additions (NH₄NO₃) at rates of three- and ten-fold ambient atmospheric deposition (8.5 kg ha⁻¹ year⁻¹) were realised in an acid- and base-poor northern hardwood forest of Québec, Canada. Soil solution chemistry, foliar chemistry, crown dieback and basal area growth of sugar maple (Acer saccharum Marsh.) were measured. Except for a transitory increase of NO₃ and NH₄ concentrations, there was no persistent increase in their level in soil solution 3 years after N treatments, with the exception of one plot out of three, that received the highest N addition, beginning to show persistent and high NO₃ concentrations after 2 years of N additions. Three years of N additions have significantly increased the N DRIS index of sugar maple but not N foliar concentration. Potassium, Ca and Mn foliar concentrations, as well as P and Ca DRIS indices, decreased in treated plots after 3 years. No treatment effect was observed for basal area growth and dieback rate. One unexpected result was the significant decrease in foliar Ca even in the treated plots that received low N rates, despite the absence of significant NO₃-induced leaching of Ca. The mechanism responsible for the decrease in foliar Ca is not known. Our results, however, clearly demonstrate that increased N deposition at sites with low base saturation may affect Ca nutrition even when clear signs of N saturation are not observed.

Forests

Scientific Article

Ecosystems and Environment, Forest Ecology, Forestry Research, Forests

Houle, Daniel, Moore, Jean-David

MOORE, Jean-David and Daniel HOULE

2009

PDF available upon request

Available at the Direction de la recherche forestière

Acer saccharum, ecosystems and environment, sugar maple, northern hardwood, nitrogen fertilization, nitrogen saturation, forestry research scientific article