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ARS Home » Research » Publications at this Location » Publication #283547
Title: Soil Carbon Dynamics for Irrigated Corn under Two Tillage Systems

Author
item Follett, Ronald
item JANTALIA, CLAUDIA - Labex - Embrapa
item Halvorson, Ardell

Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/6/2012
Publication Date: 4/5/2013
Citation: Follett, R.F., Jantalia, C.P., Halvorson, A.D. 2013. Soil Carbon Dynamics for Irrigated Corn under Two Tillage Systems. Soil Science Society of America Journal. 77:951-963.

Interpretive Summary: Conventional plow tillage (CT) with high N rates is commonly used to grow irrigated, continuous corn (Zea mays L.) in the central Great Plains. Less common than CT is to instead use continuous no-till (NT). Both systems, with optimum irrigation and N fertilization, produce similar corn stover yields with similar stover carbon:nitrogen (C/N) ratios. We compared effects of tillage and N for their potential to maintain or sequester soil organic C (SOC) near the surface (0 to 30 cm) and deeper within the soil profile (30 to 120 cm). Stable C isotope techniques were used to understand the dynamics of soil C gains and losses. This technique provided information about the fate of C added to the soil by continuous corn (C4-C) and of the residual C3-C from cool-season plants grown prior to beginning the study. We determined change in SOC stocks under NT and CT management and relative contributions of C4-C and C3-C to change in total SOC stocks after eight crop years. No-till was superior to CT in maintaining SOC stocks. The C4-C from continuous corn was maintained under both NT and CT. Most of the change in SOC dynamics of CT vs. NT resulted from greater loss of C3-C stocks under CT throughout all sampling depths. N fertilization slowed losses of C3-C stocks and maintained C4-C stocks. Soil sampling to only 30cm may result in incomplete information about SOC sequestration. Deep soil sampling and use of stable C isotope techniques were important to the overall evaluation of soil C dynamics.

Technical Abstract: Conventional plow tillage (CT) with high N rates is commonly used to grow irrigated, continuous corn (Zea mays L.) in the central Great Plains. Less common than CT is to instead use continuous no-till (NT). Both systems, with optimum irrigation and N fertilization, produce similar corn stover yields with similar stover carbon:nitrogen (C/N) ratios. We compared effects of tillage and N for their potential to maintain or sequester soil organic C (SOC) near the surface (0 to 30 cm) and deeper within the soil profile (30 to 120 cm). Stable C isotope techniques were used to understand the dynamics of soil C gains and losses. This technique provided information about the fate of C added to the soil by continuous corn (C4-C) and of the residual C3-C from cool-season plants grown prior to beginning the study. We determined change in SOC stocks under NT and CT management and relative contributions of C4-C and C3-C to change in total SOC stocks after eight crop years. No-till was superior to CT in maintaining SOC stocks. The C4-C from continuous corn was maintained under both NT and CT. Most of the change in SOC dynamics of CT vs. NT resulted from greater loss of C3-C stocks under CT throughout all sampling depths. N fertilization slowed losses of C3-C stocks and maintained C4-C stocks. Soil sampling to only 30cm may result in incomplete information about SOC sequestration. Deep soil sampling and use of stable C isotope techniques were important to the overall evaluation of soil C dynamics.