Submitted to: ASA-CSSA-SSSA Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: July 2, 2003
Publication Date: November 2, 2003
Citation: Prior, S.A., Runion, G.B., Torbert,H.A., Rogers, H.H., and Reeves D.W. 2003. Effects of elevated atmospheric CO2 on soil carbon in conventional and conservation cropping systems. [abstract] In: Agronomy Abstracts, ASA, Madison, Wisconsin. CD-ROM. Technical Abstract: Increasing atmospheric CO2 concentration has led to concerns about potential changes to production agriculture as well as agriculture's role in sequestering C. In the fall of 1997, a study was initiated to compare the effects of elevated CO2 on two crop management systems (conventional and conservation). The study used a split-plot design replicated three times with two management systems as main plots and two CO2 levels (ambient and twice ambient) as subplots using open top chambers on a Decatur silt loam. The conventional system used a grain sorghum and soybean rotation with winter fallow and spring tillage practices. In the conservation system, sorghum and soybean were rotated and three cover crops were used (crimson clover, sun hemp, and wheat) using no till practices (in order of clover, sorghum, sunn hemp, wheat, and soybean). Biomass responses over two cropping cycles (4 years) and the effect of management on soil C were evaluated. Cumulative residue inputs were increased by elevated CO2 and conservation management. The greatest increase in soil C occurred at the 0-5 cm depth in the conservation system under CO2-enriched conditions. Smaller shifts in soil C were noted at lower depths (5-10 and 15-30 cm) due to management or CO2 level. Results suggest that with conservation management in a high CO2 environment, greater residue inputs could increase soil C storage.