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ARS Home » Plains Area » Lincoln, Nebraska » Agroecosystem Management Research » Research » Publications at this Location » Publication #246320
Title: Long-Term Soil Organic Carbon as Affected by Tillage and Cropping Systems

Author
item Varvel, Gary
item WILHELM, WALLACE - Former ARS Employee

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/23/2009
Publication Date: 3/18/2010
Citation: Varvel, G.E., Wilhelm, W.W. 2010. Long-Term Soil Organic Carbon as Affected by Tillage and Cropping Systems. Soil Science Society of America Journal. 74:3 915-921. Available: http://soil.scijournals.org/cgi/content/abstract/74/3/915?etoc

Interpretive Summary: Corn and soybean production in conservation tillage systems has increased in recent years because they provide greater soil protection, water conservation, increased yields and profits, and because of their potential to reduce losses or sequester soil organic carbon. This long-term study, initiated in 1980, was conducted to evaluate the effects of three cropping systems [continuous corn (CC), continuous soybean (CSB), and soybean-corn (SB-C)] in six primary tillage systems (chisel, disk, plow, no-till, ridge-till, and subtill) under rainfed conditions in southeastern Nebraska on soil organic carbon (C). Soil samples were collected to a depth of 30-cm in depth increments in the fall of 1989 and 2004 after harvest. No significant differences in soil organic C concentrations were obtained between tillage treatments in any depth in a partial sampling of the study that was done in 1989. Tillage treatment and cropping system both significantly affected soil organic C concentrations and stocks at all depths in 2004, but they only significantly affected bulk densities at some depths and these differences were small. No-till treatments had the greatest soil organic C concentrations and stocks, with values in the other tillage treatments somewhat less. Similarly, soil organic C concentrations and stocks were greatest in CC and least in CSB with values for the SB-C cropping system intermediate in all tillage systems. Soil organic C levels were maintained or even increased in all tillage systems, but the greatest increases were obtained in systems with the least amount of soil disturbance.

Technical Abstract: Use of conservation tillage systems for corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] production has increased in recent years because of several factors including greater soil protection, water conservation, increased yield, increased profit, and their potential to reduce losses or sequester soil organic carbon (SOC). This study was conducted to evaluate the effects of three cropping systems [continuous corn (CC), continuous soybean (CSB), and soybean-corn (SB-C)] in six primary tillage systems (chisel, disk, plow, no-till, ridge-till, and sub-till) under rainfed conditions in southeastern Nebraska on SOC. Soil samples were collected to a depth of 30-cm in depth increments of 0 to 7.5-, 7.5 to 15-, and 15 to 30-cm in the fall of 1989 and 2004 after harvest and analyzed for SOC. No significant differences in SOC concentrations were obtained between tillage treatments in any depth in a partial sampling of the study that was done in 1989. Tillage treatment and cropping system both significantly affected SOC concentrations and stocks at all depths in 2004, but they only significantly affected bulk densities at some depths and these differences were small. No-till treatments had the greatest SOC concentrations and stocks with values in the other tillage treatments somewhat less. Similarly, SOC concentrations and stocks were greatest in CC and least in CSB with values for the SB-C cropping system intermediate in all tillage systems. Soil organic C levels were maintained or even increased in all tillage systems, but the greatest increases were obtained in systems with the least amount of soil disturbance. [GRACEnet Publication]