2026-09-19T15:44:34Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/110480 2023-07-11 col_2142_5131 col_2142_14798 com_2142_5130 com_2142_686 com_2142_397

Christianson, Laura E Christianson, Laura E Pittelkow, Cameron M Nafziger, Emerson D Bollero, German Preza-Fontes, Giovani 2021-09-17T01:10:57Z 2021-09-17T01:10:57Z 2021-04-21 2021-05 Nitrogen (N) fertilizer inputs are required to maintain corn production in high-yielding cropping systems across much of the U.S. Midwest. However, applied N can also increase N losses through nitrate-nitrogen (NO3-N) leaching and nitrous oxide (N2O) emissions, negatively impacting water and air quality, respectively. Given these competing demands, there is a pressing need to develop new strategies for maintaining grain yields and economic returns while decreasing the risk of environmental N pollution. Therefore, the overall objectives of this dissertation research were to (i) evaluate the effectiveness of in-field recommended management practices for improving water quality while also assessing potential agronomic and environmental tradeoffs of those practices, and (ii) explore how process-based modeling tools could be used as an integrative approach for linking sustainability outcomes with improved agronomic efficiencies. Results from a 3-yr field experiment highlighted potential environmental tradeoffs between water and air quality when pairing in-season split N application with a cereal rye cover crop. Combining these two practices reduced NO3-N losses by 37% compared to pre-season N application alone, but soil N2O emissions also increased by 27%. Corn yields were not significantly affected by in-field management practices, indicating no agronomic tradeoffs. An analysis of 32 site-years of crop and soil data found that soil mineral N provided moderately good predictions for achieving optimum grain yields (R2 = 0.46 – 0.61). While increasing soil mineral N from deficiency to sufficiency levels increase corn yields by 22%, it also increased the probability of environmental N losses. Together, these results show that N fertilizer management and cover cropping can greatly impact production and sustainable goals. The delicate balance between productivity and environmental N losses illustrates the importance of incorporating multiple N loss pathways when developing sustainable in-field management strategies in the region. Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2021-09-16 without embargo terms The student, Giovani Preza-Fontes, accepted the attached license on 2021-04-15 at 10:01. The student, Giovani Preza-Fontes, submitted this Dissertation for approval on 2021-04-15 at 10:07. This Dissertation was approved for publication on 2021-04-21 at 16:04. DSpace SAF Submission Ingestion Package generated from Vireo submission #16343 on 2021-09-16 at 16:41:53 Made available in DSpace on 2021-09-17T01:10:57Z (GMT). No. of bitstreams: 3 PREZA-FONTES-DISSERTATION-2021.pdf: 1839272 bytes, checksum: 80555b025645418530861eff4ca9c4b1 (MD5) LICENSE.txt: 4217 bytes, checksum: f6fd9e7d0ab754cb3009982005b9e054 (MD5) PROQUEST_LICENSE.txt: 4563 bytes, checksum: 627c713b030dea3555bfb8de318fe16c (MD5) Previous issue date: 2021-04-21 application/pdf http://hdl.handle.net/2142/110480 en Copyright 2021 Giovani Preza-Fontes nitrate leaching, nitrous oxide, nitrogen, cover crops Balancing water quality, nitrogen management, and corn production goals in Illinois text Thesis Crop Sciences Crop Sciences University of Illinois at Urbana-Champaign Dissertation Ph.D.