THE EFFECTS OF PRESCRIBED BURNING ON NUTRIENT AVAILABILITY AND PRIMARY PRODUCTION IN SANDPLAIN GRASSLANDS

Prescribed burning is being used to manage sandplain grasslands in New England, particularly for rare species habitat enhancement. This study examined the effects of prescribed burning on soil nitrogen availability over time and through the soil profile of sandplain grasslands in addition to short-term primary production estimated as standing crop biomass. Nitrogen availability was increased in the short term in the surface soils of a sandplain grassland ecosystem subjected to spring burning. Mineral nitrogen leached into lower soil horizons following the first large rainstorms after fire, and was eventually significantly depleted throughout the rooting zone. The ecosystem did not return to preburn concentrations of available nitrogen within 3 yr following fire. Production of standing crop biomass over the short term varied among species following fire. There was a significant effect of burning upon standing crop biomass of the graminoids with the highest biomass observed in the unburned reference area. Furthermore, the herbaceous legume, Tephrosia virginiana, increased in aboveground biomass and flowering during the growing season immediately following the spring burn.