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

Abstract

Abstract A study was conducted to determine soil chemistry in an uncut black spruce ( Picea mariana ) forest with and without the ericaceous understory shrub Kalmia angustifolia , as well as on a cut black spruce forest currently dominated by Kalmia . The organic (humus) and mineral (Ae, upper and lower B horizons) soils associated with Kalmia from uncut and cut forests, and non- Kalmia soils from uncut forest, were analyzed for selected soil properties. In general, mineral soils (B horizon) associated with Kalmia in uncut forest have lower values for organic matter (3.25%), organic nitrogen (0.66 mg·g −1 ), Fe 3+ (95.4 μg·g −1 ) and Mn 2+ (9 μg·g −1 ), and higher values for pH (4.12) and Ca 2+ (27 μg·g −1 ) compared to non- Kalmia (organic matter, 3.43%; organic-N, 1.15 mg·g −1 ; Fe 3+ , 431 μg·g −1 ; Mn 2+ , 23.2 μg·g −1 ; pH, 3.14; Ca 2+ , 15.6 μg·g −1 ) and cut black spruce- Kalmia (organic matter, 3.74%; organic-N, 0.94 mg·g −1 ; Fe 3+ , 379 μg·g −1 ; Mn 2+ , 27 μg·g −1 ; pH, 2.87; Ca 2+ , 25.2 μg·g −1 ) forest. The high C:N ratio in Kalmia 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 leached out from Kalmia litter were lower in Kalmia associated soils than the non- Kalmia soils from the uncut forest, and Kalmia associated soils from the cut forest area. Results indicate that soils associated with Kalmia were nutrient poor particularly for nitrogen, phosphorus, iron and manganese, and provide some basis for the hypothesis that Kalmia has dominated microsites that were nutrient poor prior to Kalmia colonization.