Lysimeter and Centrifuge Soil Solutions: Seasonal Differences between Methods

Lysimetry and centrifugation were compared as variable‐tension (centrifugation) and low‐tension (lysimetry) soil‐solution collection methods. Low‐tension lysimetry and low‐ and high‐speed centrifugation with double‐bottom cups were used to collect soil solutions from each major horizon of a subalpine Spodosol. Solution samples were collected monthly and compared throughout a 1‐yr period. Few seasonal changes were observed in the cation, anion, pH, or C concentrations of the lysimetry solutions. Both low‐ and high‐speed centrifuge solutions showed a strong seasonal cycle for major cations, anions, and C; peaks occurred in winter and summer and were especially evident in the upper horizons. Centrifuge solution concentrations were frequently greater than those of the lysimeter solutions. Aluminum and Si were exceptions, with lysimetry solution concentrations equal to or greater than those of the centrifuge solutions. Centrifuge solution concentrations of Al and Si also showed increases in concentration during summer months only. Seasonal variations may be due to differences in soil water residence time or biological processes. Results suggest that both the methodology used for obtaining soil solutions and the time of sampling can influence solution composition.