SOLUTION CHEMISTRY IN A RED PINE PLANTATION 39 YEARS AFTER POTASSIUM FERTILIZATION

Accelerated leaching of nutrient cations has been hypothesized as a potential effect of acidic deposition. Nutrient-cation deficiencies resulting from accelerated cation leaching have been proposed as a contributing factor in forest decline in Europe. The objective of this study was to intensively characterize the solution chemistry of a forest ecosystem in order to assess the status of its nutrient-cation losses. Precipitation, throughfall, stemflow, and soil solution chemistry were monitored for 3 yr in a red pine (Pinus resinosa Ait.) plantation established in 1930 at the Pack Forest in the Adirondack Mountains of New York. Plots fertilized with 0, 59, and 118 kg K ha-1 in 1948 (designated C, L, and H, respectively) were studied to compare K leaching in systems of different K status and to assess the longevity of K-fertilization effects on solution chemistry. The concentration of K in throughfall and stemflow was higher in the two fertilized plots relative to the control although 39 yr had elapsed since K fertilization. Fertilized plots generally had higher K concentrations in soil solution in the 0- to 8- and 8- to 15-cm depths, whereas no differences were found among plots in the 15- to 45-cm depth. Input-output budgets indicated that much less H, NO3, and SO4 were leached below the rooting zone (0-45 cm) than were received from atmospheric (including dry) deposition. Net losses were observed for K, Ca, and Mg of 64, 294 and 17 mol(c) ha-1 yr-1 (15, 3, and 1% relative to the exchangeable pools), respectively. These losses were not large compared with other forests in the USA.