Nutrient status of black spruce (Picea mariana [Mill.] BSP) forest soils dominated by Kalmia angustifolia L.

A study was conducted to determine soil chemistry in an uncut black; spruce (Picea mariana) forest with and without the ericaceous understory shrub Ka lmia angustifolia, as well as on a cut black spruce forest currently domina ted by Kalmia. The organic (humus) and mineral (Ae, upper and lower B horiz ons) soils associated with Kalmia from uncut and cut forests, and non-Kalmi a soils from uncut forest, were analyzed for selected soil properties. In g eneral, mineral soils (B horizon) associated with Kalmia in uncut forest ha ve lower values for organic matter (3.25 %), organic nitrogen (0.66 mg.g(-1 )), Fe3+ (95.4 mu g.g(-1))and Mn2+ (9 mu g.g(-1)), and higher values for pH (4.12) and Ca2+ (27 mu g.g(-1)) compared to non-Kalmia (organic matter, 3. 43 %; organic-N, 1.15 mg.g(-1); Fe3+, 431 mu g.g(-1): Mn2+, 23.2 mu g.g(-1) ; pH, 3.14; Ca2+, 15.6 mu g.g(-1)) and cut black spruce-Kalmia (organic mat ter, 3.74 %; organic-N, 0.94 mg.g(-1); Fe3+, 379 mu g.g(-1); Mn2+, 27 mu g. g(-1): pH, 2.87; Ca2+, 25.2 mu g.g(-1)) forest. The high C:N ratio in Kalmi a mineral soil from upper B (29.73) and lower B (identified as B+) (33.08) in uncut black spruce forest was recorded compared to non-Kalmia soils in B (18.17) and B+ (17.05) horizons in uncut black spruce forest. Phenolics le ached our from Kalmia litter were lower in Kalmia associated soils than the non-Kalmia soils from the uncut forest, and Kalmia associated soils from t he cut forest area. Results indicate that soils associated with Kalmia were nutrient poor particularly for nitrogen, phosphorus, iron and manganese, a nd provide some basis for the hypothesis that Kalmia has dominated microsit es that were nutrient poor prior to Kalmia colonization. (C) Elsevier, Pari s.