Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/7/2016
Publication Date: 11/7/2016
Citation: Prior, S.A., Runion, G.B., Torbert III, H.A. 2016. Long-term pasture under elevated CO2 and N management: CO2 flux patterns upon return to cultivation [Abstract]. ASA-CSSA-SSSA Annual Meeting Abstracts. CDROM.
Technical Abstract: Soil CO2 efflux patterns associated with converting pastures back to row crop production remain understudied in the Southeastern US. A 10-year study of bahiagrass (Paspalum notatum Flüggé) response to elevated CO2 was conducted using open top field chambers on a Blanton loamy sand (loamy siliceous, thermic, Grossarenic Paleudults). Plants were subjected to ambient or elevated (ambient plus 200 ppm) CO2 and grown under managed ([(NH4)2SO4] at 90 kg ha-1 3x yr-1) and unmanaged conditions (no added N), both of which are common in the Southeast. At study termination, soil CO2 flux was continuously monitored (automated carbon efflux system or ACES) following glyphosate applications and tillage to document CO2 loss associated with pasture conversion to row crop production. Concurrent measures of the herbicide termination process were documented with an active light sensor (Greenseeker meter). Over the course of this study, biomass production was increased under high CO2 with N addition; this response was typical of C4 plants (~15%). In contrast, biomass production was unaffected by CO2 without added N. The effects of elevated CO2 and N management on soil CO2 efflux patterns associated with herbicide treatment and tillage will be discussed.