79-1 Trace Gas Fluxes, Global Warming Potential and Greenhouse Gas Intensity Related to Tillage and Nitrogen Application with and without Nitrapyrin in Rainfed Corn.

See more from this Division: ASA Section: Environmental Quality
See more from this Session: Management Practices and Land-Use Impact on Global Warming Potential and Greenhouse Gas Intensity

Monday, November 16, 2015: 1:00 PM
Minneapolis Convention Center, 102 E

Rex A. Omonode, Dept. of Agronomy., Purdue University, West Lafayette, IN, Tony J. Vyn, 915 W State St., Purdue University, West Lafayette, IN and Douglas R Smith, Grassland, Soil and Water Research Laboratory, TEMPLE, TX
Abstract:
On-farm studies were conducted in Indiana over a 3-yr period to assess effect of tillage and nitrogen (N) fertilizer application, with and without nitrapyrin (Instinct®), on seasonal carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes, global warming potential (GWP) and greenhouse gas intensity (GHGI) during corn production.  Tillage consisted of no-till (NT) and conventional tillage (CT) or reduced tillage (RT), and N was applied as UAN at a single N rate, with and without nitrapyrin (Instinct®).  Seasonal CO2, CH4, and N2O were measured weekly for up to 8 weeks, and thereafter biweekly during the growing season, and corn yield recorded at harvest.  Global warming potential due to treatment was estimated by multiplying cumulative CO2, CH4 and N2O by appropriate factors as recommended by the Inter-governmental Panel on Climate Change (IPCC) and summing across all GHGs, and GHGI was estimated by dividing GWP by yield.  Tillage and N source effects on GHG fluxes varied significantly by year and location.  The soil acted as a minor sink of CH4 across treatments or locations. No-till and RT/CT, respectively, resulted in 2055 and 2068 kg CO2 ha-1, and in 780 and 910 kg CO2-eq ha-1 of N2O emissions.  Without Instinct, UAN resulted in 2274 kg CO2 and 748 kg CO2-eq yr-1 of N2O, while UAN+Instinct resulted in 2111 kg CO2 and 539 kg CO2-eq yr-1 N2O emissions. Global warming potential ranged from 2135 to 4015 kg CO2-eq for UAN, but was 1903-3320 kg CO2-eq for UAN+Instinct.  GHGI for UAN was 0.31 kg CO2-eq kg−1 grain and was 14% greater than for UAN+Instinct, and 9% greater for NT relative to CT or RT (0.32 kg CO2-eq kg−1 grain).  Our results indicated that UAN+Instinct has the potential to reduce global warming under NT or CT/RT.

See more from this Division: ASA Section: Environmental Quality
See more from this Session: Management Practices and Land-Use Impact on Global Warming Potential and Greenhouse Gas Intensity

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