Prescribed fire, soil inorganic nitrogen dynamics, and plant responses in a semiarid grassland
Augustine, D.J., P. Brewer, D.M. Blumenthal, J.D. Derner and J.C. von Fischer. 2014. Elsevier
Abstract
In arid and semiarid ecosystems, fire can potentially affect ecosystem dynamics through changes in soil
moisture, temperature, and nitrogen cycling, as well as through direct effects on plant meristem mor-
tality. We examined effects of annual and triennial prescribed fires conducted in early spring on soil
moisture, temperature, and N, plant growth, and plant N content in semiarid shortgrass steppe. Annual
burning increased soil inorganic N availability throughout the growing season, which was associated
with increased soil temperature and a reduction in aboveground N in C3 plants. Furthermore, the in-
crease in soil inorganic N pools with annual burning was modest and did not facilitate success of ruderal
species. Negative fire effects on C3 plant production could be due to increased soil temperature, reduced
soil moisture, or direct negative effects on C3 plant meristems, although fuel loads and fire temperatures
were low relative to other grasslands. Triennial burning had intermediate effects on N availability and C3
plant production compared to annual burning and unburned controls. Results show that prescribed
burns can be used in the management of this semiarid grassland without facilitating annual plant in-
vasion, but excessively frequent burning can reduce production of C3 plants.
Key Words
Ammonium Nitrate Nitrogen cycling Plant invasion Rangeland management Soil moisture
