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Title: Elevated atmospheric CO2 effects on dairy crops in the Northeast US: comparing IFSM and DSSAT models to FACE data

Author
item CASTANO-SANCHEZ, JOSE - Pennsylvania State University
item Rotz, Clarence - Al
item KARSTEN, HEATHER - Pennsylvania State University

Submitted to: ASA-CSSA-SSSA Annual Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/19/2018
Publication Date: 11/4/2018
Citation: Castano-Sanchez, J.P., Rotz, C.A., Karsten, H.D. 2018. Elevated atmospheric CO2 effects on dairy crops in the Northeast US: comparing IFSM and DSSAT models to FACE data. ASA-CSSA-SSSA Annual Meeting Abstracts. P. 1.

Interpretive Summary: No Interpretive Summary is required for this Abstract. JLB.

Technical Abstract: Atmospheric CO2 concentration has increased since the industrial revolution. The current level is 410 ppm and it is expected to be between about 500 ppm (RCP 4.5 – current trend) and 540 ppm (RCP 8.5) by mid-century. Crop models have incorporated the effects of CO2 on crop growth and evapotranspiration (ET) reduction based upon environmental chamber and free air (FACE) experiments from the 1990s. Before evaluating climate change projections on crop production, we tested how accurately two locally calibrated agroecosystems models, IFSM and DSSAT predicted FACE data. In the Northeastern U.S., dairy production is a major contributor to the agricultural economy. Primary feed crops in the region are alfalfa and maize, with some soybean and small grains. We evaluated the response of IFSM and DSSAT, using 25 years of recorded weather of State College, PA (1990-2014) with two levels of CO2 380 ppm (baseline) and 550 ppm (FACE experiments and RCP 8.5). Model simulation results were compared with FACE experimental results summarized by Kimball (2016). Predicted average annual yield increase over this period was 11% (IFSM) and 14% (DSSAT) for C3 grass (wheat) compared to 19% from FACE data. Increases for soybean were 15% (IFSM) and 24% (DSSAT) and alfalfa was 17% (IFSM) and 20% (DSSAT) where FACE data indicate 16% for C3 legumes. For C4 grass (maize), IFSM predicted 5% and DSSAT 10% (DSSAT) while FACE data vary from 0% to 30%. For both models, the reduction in ET for all crops was 0.007-0.01%; whereas, the recorded ET reduction in FACE experiments was 5% for C3 grasses, 12% for C3 legumes and 0% to 13% for C4 grasses. These preliminary results show that the models can represent the crop yield increase as atmospheric CO2 increases, but modeled decreases in ET were much lower than that measured in FACE experiments.