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ARS Home » Plains Area » Brookings, South Dakota » Integrated Cropping Systems Research » Research » Publications at this Location » Publication #295882
Title: Soil C sequestration and agronomic yield of diverse crop rotations under no-till soil management

Author
item Riedell, Walter
item Osborne, Shannon
item PIKUL, JOSEPH - Retired ARS Employee
item SCHUMACHER, THOMAS - South Dakota State University

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/28/2012
Publication Date: 10/24/2012
Citation: Riedell, W.E., Osborne, S.L., Pikul, J.L., Schumacher, T.E. 2012. Soil C sequestration and agronomic yield of diverse crop rotations under no-till soil management. American Society of Agronomy/Crop Science Society of America/Soil Science Society of America annual meeting, Cincinnati OH, October 21-24, 2012. Abstract. Available: www.agronomy.org/publications/meetings/2012am/10155/71697.

Interpretive Summary: Diversified crop rotations, which reduce risk associated with adoption of no-till soil management, may influence soil carbon sequestration. This study measured effects of annual crop rotations of increasing diversity (corn-soybean 2-yr rotation, corn-soybean-oat/pea hay 3-yr rotation, or corn-soybean-oat/pea hay-alfalfa-alfalfa 5 year rotation) on grain yield, stover/hay biomass, stover C, and soil C in soil converted to no-till management in 1996. For the 2008 and 2009 growing seasons, average grain yield from the corn phase across all rotations was 160 bushels per acre (bu/ac) while soybeans yielded 30 bu/ac. Corn stover remaining in the field after harvest was 4.7 tons per acre (tons/ac) which contained 2.1 tons/ac of carbon. Soybean stover remaining was 1.0 ton/ac and contained 0.4 ton/ac of carbon. Hay from oat/pea and alfalfa phases of the rotations was harvested and removed each year, so no carbon was added to the soil from above ground portions of these crops. From 1999 to 2007, soil carbon was sequestered at a rate of 127 pounds of carbon per acre per year (lbs/ac/year) for the 2-yr rotation, 10 lbs/ac/yr for the 3-yr rotation, and 226 lbs/ac/yr for the 5-yr rotation. This greater carbon sequestration rate for the 5-yr rotation indicates that perennial forages included as rotational crops strongly increase soil carbon levels. The low carbon sequestration rate for the 3-yr rotation indicates that inclusion of an annual forage crop as the third phase of the rotation does not compensate for the reduction in the number of corn phases (and in the amount of stover carbon returned) that were present in the 2-yr rotation. Thus, greater crop rotational diversity when converting to no-till soil management may not always result in greater soil carbon sequestration.

Technical Abstract: Diversified crop rotations, which reduce risk associated with adoption of no-till soil management, may influence soil C sequestration and soil quality. This study measured effects of corn-soybean (C-S), corn-soybean-oat/pea hay (C-S-H), or corn-soybean-oat/pea hay-alfalfa-alfalfa (C-S-H-A-A) annual rotations on grain yield, stover/hay biomass, stover C, and soil C (0-7.5 cm depth) in soil converted to no-till management in 1996. Averaged over the last 2 yr of the experiment, grain yield from the corn phase of all rotations was 10.03 Mg/ha while soybeans yielded 1.84 Mg/ha. Corn stover remaining in the field after harvest was 10.61 Mg/ha and contained 4.80 Mg/ha C while that for soybean stover was 2.19 Mg/ha and contained 0.95 Mg/ha C. The oat/pea phase produced 5.35 Mg/ha hay while alfalfa produced 2.95 Mg/ha hay. Soil C sequestration rates, extrapolated from soil C measurements made in 1999 and 2007, were 142.4 kg C/ha/yr for C-S, 11.5 for C-S-H, and 253.1 for C-S-H-A-A. The C sequestration rate for C-S was intermediate between the other rotations. The greater C sequestration rate for C-S-H-A-A indicates that perennial forages included as rotational crops strongly increase soil C levels. The low C sequestration rate for C-S-H indicates that inclusion of oat/pea hay as a third rotational crop may not compensate for the reduction in the number of corn phases (and in the amount of stover C returned) that were present in the C-S rotation. Thus, greater crop rotational diversity when converting to no-till soil management may not always result in greater soil C sequestration.