Solution concentrations of nutrient ions below the rooting zone of a sugar maple stand: relations to soil moisture, temperature, and season

Abstract

Temporal variations of ion concentrations in soil solution were analyzed in relation to soil percolate volume, soil water content, soil temperature, solution chemistry, and season. The study site was an uneven-aged, mature northern tolerant hardwoods dominated by sugar maple (Acersaccharum Marsh.) within the Turkey Lakes Watershed, Ontario. Six ions were investigated: nitrate (NO ₃ ⁻), sulfate (SO ₄ ²⁻), calcium (Ca ²⁺), magnesium (Mg ²⁺), potassium (K ⁺), and ammonium (NH ₄ ⁺). Nitrate concentrations in the soil solution depended on season during the nonfoliage period and responded directly to forest floor percolation, soil water content, and season during the foliage period. Variations of SO ₄ ²⁻, Ca ²⁺, and Mg ²⁺ concentrations were mostly attributable to NO ₃ ⁻ concentration, and to season to a lesser extent. Concentrations of K ⁺ and NH ₄ ⁺ correlated only weakly to any of the "independent" variables included in the analysis, reflecting a high affinity between these ions and the soil colloids.