Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/5/2000
Publication Date: 11/5/2000
Citation: Prior, S.A., Torbert, H.A., Kimball, B.A., and Rogers, H.H. 2000. Free-air CO2 enrichment of sorghum: Soil carbon and nitrogen dynamics. In Agronomy Abstracts. p. 19. ASA, Madison, WI.
Technical Abstract: The positive impact of elevated atmospheric CO2 concentration on crop biomass production suggests that more carbon will reach the soil. An aspect of soil carbon sequestration that requires further study is the effect of elevated CO2 on soil carbon and nitrogen dynamics; this relationship is key to understanding potential long-term carbon storage in soil. Soil samples (0-5, 5-10, and 10-20 cm increments) were collected after two years of grain sorghum [Sorghum bicolor (L.) Moench.] production under two CO2 levels [370 (ambient) and 550 ppm (free-air CO2 enrichment) (FACE)] and two water treatments (adequately- watered and water-stress) on a Trix clay loam (fine, loamy, mixed (calcareous), hyperthermic Typic Torrifluvents) at Maricopa, AZ. In addition to assessing treatment effects on soil organic carbon and total nitrogen, potential carbon and nitrogen mineralization and carbon turnover were determined in a 60 day laboratory incubation study. Changes in these measures will be discussed.