Project Number: 5012-21000-030-11-N
Project Type: Non-Funded Cooperative Agreement
Start Date: Apr 17, 2017
End Date: Feb 29, 2020
Objective 1: Conduct T-FACE experiments for soybean across a range of temperature increases to acquire response curves of various processes, and empirically attribute and partition different mechanisms of high temperature impacts on crop yield. Objective 2: Use the CLM-APSIM model at the site level to reproduce the response curves and experiment results acquired from experiments in Objective 1 and other data from previous T-FACE experiments. Use the calibrated model to empirically attribute and partition different mechanisms of high temperature impacts on crop yield at the site level, and also attribute the historical yield loss due to increase temperature to different physiological mechanisms at the county scale for the U.S. Corn Belt. Objective 3: Use the improved and calibrated CLM-APSIM model to (1) project crop yield impacts for the U.S. Corn Belt without any adaptations under the various climate scenarios at 2050, and quantify the contribution of each mechanism; and (2) assess potential benefits in crop yield for different hypothetical breeding improvements and identify options for climate change adaptation.
We will focus on the following four major mechanisms: (1) direct temperature effects on photosynthesis and respiration; (2) acceleration of the crop growth rate and shortening of the growing season in both vegetative and reproductive stages; (3) direct heat stress effects on reproductive stages, including seed number (flowers and pods produced and aborted) and seed size (during grainfilling); (4) high-temperature induced increase of atmospheric water demands. We propose to analyze all the major mechanisms in one framework (experiments and modeling), and ideally aim for a convergent answer. We will utilize a combined in-field heating technique coupled with parameterization and utilization of ecosystem models to meet these goals.