GC119-0001
Assessing impacts of pre-growing-season weather on the response of corn yield to nitrogen fertilizer rate in the U.S. Midwest

Wednesday, 16 December 2020
Poster
Ziyi Li, University of Illinois at Urbana-Champaign, Urbana, IL, United States, Kaiyu Guan, University of Illinois at Urbana Champaign, College of Agricultural, Consumer and Environmental Sciences, Urbana, IL, United States, Wang Zhou, University of Illinois at Urbana Champaign, Department of Natural Resources and Environmental Sciences, Urbana, IL, United States, Bin Peng, University of Illinois at Urbana Champaign, National Center for Supercomputing Applications, Urbana, IL, United States, Robert F Grant, University of Alberta, Department of Renewable Resources, Edmonton, AB, Canada, Emerson D Nafziger, University of Illinois at Urbana Champaign, Department of Crop Sciences, Urbana, IL, United States, Zhenong Jin, University of Minnesota-Twin Cities, Department of Bioproducts and Biosystems Engineering, Saint Paul, MN, United States, Jinyun Tang, Lawrence Berkeley National Lab, Berkeley, CA, United States, Yaping Cai, University of Illinois at Urbana Champaign, College of Agricultural Consumer and Environmental Sciences, Urbana, IL, United States and Ziqi Qin, University of Illinois at Urbana-Champaign, Champaign, IL, United States
Abstract:
Improving nitrogen use efficiency (NUE) is urgently needed to achieve the co-sustainability of food productivity and environmental quality. Both environmental conditions (i.e. climate and soil) and land management practices influence the nitrogen (N) cycle in agroecosystem. Weather conditions during the pre-growing season (i.e. winter and early spring) is one of the vital environmental factors that can influence the amount of available soil inorganic nitrogen at the start of growing season, and finally affects crop yield. To evaluate impacts of pre-growing season weather on the response of corn yield to N fertilizer rate, we first validated an advanced agroecosystem model, Ecosys, with N field trial data collected around the U.S. Midwest, and then used the Ecosys model to simulate the N cycle and crop yield under different pre-growing season weather conditions. Specifically, we collected data from 70 field trials that spanned during 1999-2008 across Illinois (each trial had different fertilizer rates) and 4 sites with more observations (i.e. soil N concentrate, mineralization rate, N lenching amount) around the U.S. Midwest for the model evaluation. The validation results show that Ecosys simulated fertilizer-yield response and N cycle processes are consistent with measured ones from the trials. We further conducted the analysis with three different pre-growing season weather conditions: (i) warmer/colder pre-growing season, (ii) wetter/drier pre-growing season, and (iii) warmer/colder and wetter/drier pre-growing season. We found that (1) warmer pre-growing season can lead to higher yield, mainly due to more mineralization and less N leaching (higher temperature, smaller snowpack in winter, and less discharge is spring); (2) Wetter pre-growing season can result in lower crop yield due to larger N leaching during this period; and (3) the effects of colder pre-growing on the crop yield deficit is larger than that caused by the wetter pre-growing season. Our findings provide useful insights to guide the farmers on fertilizer application (i.e. fertilizer time and amount) around the U.S. Midwest.
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