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United States Department of Agriculture

Agricultural Research Service

Title: Co2 Evolution Froim a Tallgrass Prairie

Authors
item Franzluebbers, K - MISCELANEOUS
item Franzluebbers, Alan
item Jawson, Michael

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 27, 2001
Publication Date: N/A

Interpretive Summary: Grasslands comprise at least a quarter of the global plant cover and occur throughout a wide environmental range. Local environmental controls on carbon cycling in grasslands are complicated, because of the difficulty in separating carbon fluxes derived from plant activity from those derived from microbial activity. However, there is a great need to better understand carbon cycling in terrestrial ecosystems in light of recent global change concerns and potential carbon sequestration in soil. Carbon dioxide is removed from the atmosphere through photosynthesis by plants and animals and released back into the atmosphere through metabolic respiration by plants and decomposition of organic matter in the soil by microorganisms. Our objective was to quantify temporal and spatial components of carbon dioxide release into the atmosphere from a tall-grass prairie in northeastern Kansas. More carbon dioxide was released from areas shigher in soil organic matter and when soil temperatures were higher and when soil was moister. We developed a mathematical expression to predict carbon dioxide release into the atmosphere based on soil temperature, soil water content, and time of the year (mimicking plant development).

Technical Abstract: Environmental controls on carbon cycling in native grasslands are complicated, because of the difficulty in separating carbon fluxes derived from plant activity from those derived from microbial activity. However, there is a great need to better understand carbon cycling in terrestrial ecosystems in light of recent global change concerns. Our objective was to quantify temporal and spatial components of nocturnal carbon dioxide evolution from soil and from soil plus vegetation using static chambers with alkali absorption during two years on a tallgrass prairie in northeastern Kansas. Carbon dioxide evolution from soil was spatially related to soil organic carbon. Temporal variations in carbon dioxide evolution were related to soil temperature, water-filled pore space, and day of the year. Day of the year mimicked a plant growth rate function, which simulated an important variable controlling carbon dioxide evolution from vegetation (i.e., dark respiration), as well as carbon dioxide evolution from soil (i.e., root and microbial respiration). From an independent data set reported from a nearby location in other years, our regression equation reasonably predicted variations in carbon dioxide evolution from soil (r-square=0.76, n=31).

Last Modified: 10/23/2014
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