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oai:www.ideals.illinois.edu:2142/98363 2023-07-11 col_2142_14798 col_2142_5131 com_2142_686 com_2142_397 com_2142_5130

Pittelkow, Cameron M. Graham, Rebecca Faye 2017-09-29T17:56:41Z 2017-09-29T17:56:41Z 2017-07-11 2017-08 Nitrous oxide (N2O) is a potent greenhouse gas (GHG) with about 300 times the global warming potential of CO2 and significant levels of this GHG come from agriculture. A two-year field experiment was conducted to assess the ability of enhanced efficiency nitrogen fertilizers (EENFs) to minimize yield-scaled N2O emissions while maintaining nutrient utilization and crop productivity of maize. In addition to an unfertilized control (zero N), N source treatments applied at 202 kg ha-1 at planting included anhydrous ammonia (AA), UAN + nitrapyrin, ESN, and SuperU. Gas samples were collected using static closed chambers. Soil inorganic N concentrations, soil temperature, and precipitation were monitored throughout the growing seasons. Crop N content, grain yield, and nitrogen recovery efficiency (NRE) were also determined each year. Over the two-year trial, we found that EENFs did not consistently reduce N2O emissions or increase grain yields relative to the conventional AA treatment. Soil N concentrations were not correlated with daily N2O flux rates. In 2015, injected UAN + nitrapyrin increased N2O and yield-scaled N2O emissions relative to the other N sources, while AA produced the highest emissions in 2016, but not the highest yield-scaled emissions. These results indicate the difficulty in identifying ways to decrease yield-scaled N2O emissions using different N sources under variable weather conditions each year that likely influenced fertilizer N transformations in soil. Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2017-09-29 without embargo terms The student, Rebecca Graham, accepted the attached license on 2017-07-10 at 16:05. The student, Rebecca Graham, submitted this Thesis for approval on 2017-07-10 at 16:07. This Thesis was approved for publication on 2017-07-11 at 15:04. DSpace SAF Submission Ingestion Package generated from Vireo submission #11380 on 2017-09-29 at 11:29:37 Made available in DSpace on 2017-09-29T17:56:41Z (GMT). No. of bitstreams: 2 GRAHAM-THESIS-2017.pdf: 270676 bytes, checksum: 6949b457b6109832c855dead68987acf (MD5) LICENSE.txt: 4211 bytes, checksum: b39a2ec70dc3399e9613422382834f16 (MD5) Previous issue date: 2017-07-11 application/pdf http://hdl.handle.net/2142/98363 en Copyright 2017 Rebecca Graham Nitrogen Nitrous oxide (N2O) Enhanced efficiency fertilizers Climate change Soil fertility Soil Impacts of enhanced efficiency nitrogen fertilizers on yield-scaled N2O emissions in Illinois maize text text Crop Sciences Crop Sciences University of Illinois at Urbana-Champaign Thesis M.S.