Carbon dioxide fluxes over a northern, semiarid, mixed-grass prairie

• Published in: Agricultural and forest meteorology Vol. 108; no. 4; pp. 317 - 326
• Main Authors: Frank, A.B, Dugas, W.A
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 02.07.2001; Oxford Elsevier; New York, NY
• Subjects: Agricultural and forest climatology and meteorology. Irrigation. Drainage; Agricultural and forest meteorology; Agronomy. Soil science and plant productions; Biological and medical sciences; Bowen ratio; Carbon budget; Carbon dioxide uptake; Climatology, meteorology; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Generalities. Techniques. Climatology. Meteorology. Climatic models of plant production; Global carbon cycle; Natural ecosystems; Great Plains of America; North America; America; Mandan, North Dakota; Natural ecosystems; Carbon dioxide uptake; Carbon budget; Global carbon cycle; Bowen ratio; Carbon cycle; Grassland; Climatology; Material flow; Semi arid zone; Ecosystem; Carbon dioxide; Gas exchange; Experimental study; Carbon balance
• ISSN: 0168-1923; 1873-2240
• DOI: 10.1016/S0168-1923(01)00238-6

Temperate grassland ecosystems are an important component of the global carbon (C) cycle. The Bowen ratio/energy balance (BREB) technique was used to measure CO 2 fluxes over a mixed-grass prairie at Mandan, ND from 24 April to 26 October in 1996–1999. Above-ground biomass and leaf area index (LAI) were measured about every 21 days throughout the season. Root biomass and soil organic C and nitrogen (N) contents to 1.1 m depth were measured in mid-July each year. Peak above-ground biomass typically occurred between mid-July to early-August and ranged from 782 kg ha −1 in 1998 to 1692 kg ha −1 in 1996. Maximum LAI ranged from 0.3 in 1998 to 0.5 in 1999. Root biomass ranged from 12.7 mg ha −1 in 1996 to 16.2 mg ha −1 in 1997. Maximum daily CO 2 fluxes generally coincided with periods of maximum above-ground biomass. Total CO 2 flux for the 24 April to 26 October period ranged from 181 g CO 2 m −2 in 1998 to 474 g CO 2 m −2 in 1999 (positive flux is CO 2 movement from atmosphere to plants or soil). The 4-year average flux for this period was 345 g CO 2 m −2. Fluxes during the 1999–2000 dormant season were estimated from BREB (−349 g CO 2 m −2) and soil flux (−265 g CO 2 m −2) measurements and when combined with the growing season fluxes, resulted in estimated annual fluxes in 1999 of 125 and 209 g CO 2 m −2 for BREB and soil flux dormant season measurements, respectively. These results suggest that the C budget of Northern Great Plains mixed-grass prairie grasslands may be near equilibrium.