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Concentrations, loads, and yields of organic carbon in streams of agricultural watersheds

Journal of Environmental Quality

By:
,
DOI: 10.2134/jeq2012.0045

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Abstract

Carbon is cycled to and from large reservoirs in the atmosphere, on land, and in the ocean. Movement of organic carbon from the terrestrial reservoir to the ocean plays an important role in the global cycling of carbon. The transition from natural to agricultural vegetation can change the storage and movement of organic carbon in and from a watershed. Samples were collected from 13 streams located in hydrologically and agriculturally diverse watersheds, to better understand the variability in the concentrations and loads of dissolved organic carbon (DOC) and particulate organic carbon (POC) in the streams, and the variability in watershed yields. The overall annual median concentrations of DOC and POC were 4.9 (range: 2.1–6.8) and 1.1 (range: 0.4–3.8) mg C L−1, respectively. The mean DOC watershed yield (± SE) was 25 ± 6.8 kg C ha−1 yr−1. The yields of DOC from these agricultural watersheds were not substantially different than the DOC yield from naturally vegetated watersheds in equivalent biomes, but were at the low end of the range for most biomes. Total organic carbon (DOC + POC) annually exported from the agricultural watersheds was found to average 0.03% of the organic carbon that is contained in the labile plant matter and top 1 m of soil in the watershed. Since the total organic carbon exported from agricultural watersheds is a relatively small portion of the sequestered carbon within the watershed, there is the great potential to store additional carbon in plants and soils of the watershed, offsetting some anthropogenic CO2 emissions.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Concentrations, loads, and yields of organic carbon in streams of agricultural watersheds
Series title:
Journal of Environmental Quality
DOI:
10.2134/jeq2012.0045
Volume
41
Issue:
6
Year Published:
2012
Language:
English
Publisher:
American Society of Agronomy
Publisher location:
Madison, WI
Contributing office(s):
Minnesota Water Science Center
Description:
10 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Environmental Quality
First page:
1874
Last page:
1883
Time Range Start:
1996-01-01
Time Range End:
2008-12-31
Country:
United States
State:
California;Indiana;Iowa;Maryl;Mississippi;Nebraska;Washington