Acidic deposition has contributed to the loss of base cations, such as calcium, from forest soils in the Adirondack region of New York, USA. In September 2005 and again in April 2006, we added lime (4.1T CaCO3/ha) to small experimental plots (0.16 ha) in the western Adirondacks and determined the short-term effects of the lime addition on soil respiration rates, standing biomass of fine roots (<1 mm diameter), and fine root production in summer 2006. We estimated respiration rates using a static chamber technique and used fine root growth into in situ screens, placed horizontally in the Oe horizon, as an index of fine root production. We also conducted a lab microcosm experiment where we measured respiration rates of ambient and lime-added soils at different levels of moisture and temperature. Lime addition did not significantly affect fine root production or standing biomass (p > 0.05). In June and August 2006, rates of soil respiration were similar in limed and control plots, but were significantly different in July (p < 0.001) when soil moisture and temperature were both high. The microcosm experiment showed significant effects of liming (p < 0.001), liming x temperature (p < 0.001), and liming x moisture (p < 0.001) on respiration rates, suggesting the difference in respiration rates between limed and control plots in July was likely due the combined effects of temperature and moisture. Our data show that belowground functional response to lime addition in Adirondack soils is closely tied to soil temperature and moisture.
