Plant functional type effects on trace gas fluxes in the shortgrass steppe

Publication Type:

Journal Article

Source:

BIOGEOCHEMISTRY, Amer Soc Agron Soil Sci Soc Amer, Volume 42, Number 1-2, VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS, p.145-168 (1998)

Keywords:

C(3) and C(4) plant functional types, Grasslands, methane oxidation, nitric oxide, nitrous oxide

Abstract:

Plant community structure is expected to regulate the microbial processes of nitrification and denitrification by controlling the availability of inorganic N substrates. Thus it could also be a factor in the concomitant release of NO and N(2)O from soils as a result of these processes. C(3) and C(4) plants differ in several attributes related to the cycling of nitrogen and were hypothesized to yield differences in trace gas exchange between soil and atmosphere. In this study we estimated fluxes of NO, N(2)O and CH(4) from soils of shortgrass steppe communities dominated by either C(3) plants, C(4) plants or mixtures of the two types. We collected gas samples weekly from two sites, a sandy clay loam and a clay, throughout the growing seasons of 1995 and 1996. Plant functional type effects on gas fluxes at the clay site were not apparent, however we found several differences among plant communities on the sandy clay loam. CH(4) uptake from atmosphere to soil was significantly greater on C(4) plots than C(3) plots in both years. NO fluxes were significantly greater from C(4) plots than from C(3) plots in 1995. NO fluxes from C(3) and mixed plots were not significantly different between 1995 and 1996, however fluxes from C(4) plots were significantly greater in 1995 compared to 1996. Results indicate that under certain environmental conditions, particularly when factors such as moisture and temperature an not limiting, plant community composition can play an important role in regulating trace gas exchange.

Notes:

Symposium on Plant-Induced Soil Changes - Processes and Feedbacks at the American-Society-of-Agronomy-Soil-Science-Society-of-America Annual Meeting, INDIANAPOLIS, IN, NOV 04-08, 1996