Soil organic matter and CO2 emission as affected by water erosion on field runoff plots |
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| Authors: | VO Polyakov R Lal |
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| Institution: | 1. Estaci?n Experimental de Aula Dei (EEAD-CSIC), 1005 Avda. Montañana, Zaragoza, Spain;2. Department of Civil and Environmental Engineering, Pratt School for Engineering, Duke University, Durham, NC, USA;3. Environmental Science Program, University of Northern British Columbia, 3333 University Way, Prince George, British Columbia, V2N 4Z9, Canada;4. Estación Experimental de Aula Dei (EEAD-CSIC), 1005 Avda. Montañana, Zaragoza, Spain;1. Institut für Geographie der Universität Augsburg, Germany;2. Geographisches Institut der Universität zu Köln, Germany;3. Earth & Life Institute, TECLIM, Université catholique de Louvain, Louvain-la-Neuve, Belgium;1. São Carlos School of Engineering (EESC), University of São Paulo (USP), CxP. 359, São Carlos, SP 13566-590, Brazil;2. USDA-ARS National Soil Erosion Research Laboratory, Purdue University, 275 S. Russell St., West Lafayette, IN 47907-2077, USA;3. Federal University of Mato Grosso do Sul, CxP. 549, Campo Grande, MS 79070-900, Brazil.;4. USDA-ARS Southwest Watershed Research Center, 2000 E. Allen Rd., Tucson, AZ 85718, USA |
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| Abstract: | Soil organic carbon (SOC) is an important component of the global carbon cycle. Its dynamics depends upon various natural and anthropogenic factors including soil erosion. A study on Miamian silty clay loam soil in central Ohio was conducted to investigate the effect of soil erosion on SOC transport and mineralization. Runoff plots 10, 20 and 30 m long on a 7% slope under natural rainfall were used. Total soil loss, evolution of CO2 from the displaced aggregates of various fractions, and total SOC concentrations were determined. It was shown that the primary ways of SOC loss resulted from two processes: 1) mechanical preferential removal of SOC by overland flow and 2) erosion-induced mineralization. Significant amounts of SOC mobilized by erosion at the upper part of the slope during the season (358 kg ha? 1) could be lost to the atmosphere within 100 days (15%) and transported off site (44%). Breakup of initial soil aggregates by erosive forces was responsible for increased CO2 emission. During the initial 20 days of incubation the amount of CO2 released from coarse size sediment fractions (0.282 g C kg? 1 soil d? 1) was 9 times greater than that in fine fractions (0.032 g C kg? 1 soil d? 1) due to the greater initial amount of SOC and its exposure to the environment. Sediment size distribution as well as its residence time on the site was the primary controllers of CO2 loss from eroded soil. |
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