Increasing the sink: agricultural management and soil carbon dynamics: western U.S. croplands. In: Liebig, M., Franzluebbers, A., and Follet, R., editors. Managing agricultural greenhouse gasses. 1st edition. Waltham, MA

Authors: Collins, Harold; Mikha, Maysoon; BROWN, T - Washington State University; Smith, Jeffrey; Huggins, David; Sainju, Upendra

Submitted to: Elsevier
Publication Type: Book / Chapter
Publication Acceptance Date: 3/2/2011
Publication Date: 6/20/2012
Citation: Collins, H.P., Mikha, M.M., Brown, T.T., Smith, J.L., Huggins, D.R., Sainju, U.M. 2012. Increasing the sink: agricultural management and soil carbon dynamics: western U.S. croplands. In: Liebig, M., Franzluebbers, A., and Follet, R., editors. Managing agricultural greenhouse gasses. 1st edition. Waltham, MA. Elsevier. p. 59-78.

Interpretive Summary: The purpose of this chapter is to provide a short review and update of potential crop management practices that have had beneficial or detrimental effects on soil C storage in Western U.S. croplands, with emphasize on studies reported since 2005. This review of published literature indicates that C storage studies in the Western U.S. are still quite limited. Maintaining or increasing SOC has been a challenge in the Western U.S. because crop biomass yields and C inputs are often lower in drylands than in humid regions due to limited precipitation and shorter growing season. As a result, it often takes a long time to increase soil C storage. Novel management practices, such as reduced tillage, continuous cropping, and increased cropping intensity, can increase soil C storage compared with the conventional system. For decades, predominate cropping system in the dryland regions of the Western U.S. central Great Plains has been winter wheat-summer fallow that combined with conventional tillage (CT) further promoted SOC decomposition and soil losses through erosion. It has been well documented that tillage (i) enhances residue decomposition by mixing the residue with soil, (ii) exposes previously protected SOC to soil fauna by destroys soil aggregates, and (iii) increases soil losses due to wind and water erosion. Adopting no-tillage (NT) increases residue accumulation and surface SOC due to less soil disturbance, less residue mixing and oxidation, and decreased risks of soil erosion in addition to improve soil water during the fallow period compared with a CT system. Although with currently only low adoption in the Western U.S. NT has shown improved soil water conservation and some increase in soil C storage. This review has found that intensive cropping systems (perennial) combined with reduced tillage and fewer fallows provide more residues, increase SOC content, and reduce the potential for soil erosion

Technical Abstract: The purpose of this chapter is to provide a short review and update of potential crop management practices that have had beneficial or detrimental effects on soil C storage in Western U.S. croplands, with emphasize on studies reported since 2005. This review of published literature indicates that C storage studies in the Western U.S. are still quite limited. Maintaining or increasing SOC has been a challenge in the Western U.S. because crop biomass yields and C inputs are often lower in drylands than in humid regions due to limited precipitation and shorter growing season. As a result, it often takes a long time to increase soil C storage. Novel management practices, such as reduced tillage, continuous cropping, and increased cropping intensity, can increase soil C storage compared with the conventional system. For decades, predominate cropping system in the dryland regions of the Western U.S. central Great Plains has been winter wheat-summer fallow that combined with conventional tillage (CT) further promoted SOC decomposition and soil losses through erosion. It has been well documented that tillage (i) enhances residue decomposition by mixing the residue with soil, (ii) exposes previously protected SOC to soil fauna by destroys soil aggregates, and (iii) increases soil losses due to wind and water erosion. Adopting no-tillage (NT) increases residue accumulation and surface SOC due to less soil disturbance, less residue mixing and oxidation, and decreased risks of soil erosion in addition to improve soil water during the fallow period compared with a CT system. Although with currently only low adoption in the Western U.S. NT has shown improved soil water conservation and some increase in soil C storage. This review has found that intensive cropping systems (perennial) combined with reduced tillage and fewer fallows provide more residues, increase SOC content, and reduce the potential for soil erosion