Liming effects on some chemical and biological parameters of soil (spodosols and histosols) in a hardwood forest watershed

Abstract

Acidic lakes and streams can be restored with base application (usually limestone) provided that the base does not wash out before the benefits of alkalization can be realized; liming soils of the adjoining watershed may be an alternative approach. This study was conducted to provide a scientific basis for soil liming. Plots (50 m²) with different limestone dosages (e.g. 0, 5, 10 or 15 Mg CaCO₃ ha⁻¹) were established on each of two different soils (a Spodosol and a Histosol) in the Woods Lake watershed of the Adirondack Park Region of New York, USA. Six months after soil liming much of the added limestone was still present in both the Spodosol and in the Histosol. Ten months after soil liming results indicated that: (1) soil pH increased (>1 unit) but mostly in the top 1 cm; (2) net N mineralization increased from 9.6 to ca. 15 µg N g⁻¹ d⁻¹ and nitrification increased from 2.8 to ca. 8 µg N g⁻¹ d⁻¹; (3) denitrification was not affected (98 µg N g⁻¹ d⁻¹); (4) CO₂ production potential decreased in the surface soil and as a function of limestone dosage (60 to 6 µmol g⁻¹ d⁻¹); and (5) soluble SO ²⁻₄ concentrations in the Histosol were not affected (105 µmol L⁻¹). Liming acidic forest soils with >5 Mg CaCO₃ ha⁻¹ may increase the soil's acid neutralizing capacity, which could provide long-term benefits for surface water acidification.