Interactive effects of elevated ozone and temperature on growth and yield of soybean (Glycine max (L.) Merr.) under field conditions

Authors: Burkey, Kent; Tisdale, Ripley; ZOBEL, RICHARD - North Carolina State University; Ray, Sam; Pursley, Walter

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/12/2020
Publication Date: 11/17/2020
Citation: Burkey, K.O., Tisdale, R.H., Zobel, R.W., Ray, S.J., Pursley, W.A. 2020. Interactive effects of elevated ozone and temperature on growth and yield of soybean (Glycine max (L.) Merr.) under field conditions. Agronomy. 10:1803. https://doi.org/10.3390/agronomy10111803.
DOI: https://doi.org/10.3390/agronomy10111803

Interpretive Summary: Climate change includes many environmental stress factors including ozone air pollution and elevated temperature. While these stresses occur naturally in combination, they are typically studied individually due to limitations in technology for applying multiple stresses simultaneously. In this study, USDA-ARS scientists and engineers at Raleigh, North Carolina developed and deployed a field exposure system to study ozone and elevated temperature interactions in replicated field trials. A single soybean cultivar “Jake” was exposed to combinations of moderate ozone stress and an elevated temperature of +3.5 degrees Celsius (simulating the maximum projected future temperature associated with climate change). Cultivar “Jake” was shown to be extremely sensitive to heat stress and relatively ozone tolerant. Importantly, no apparent interactions between ozone and temperature were found, a finding that will help inform efforts to model plant stress response.

Technical Abstract: Elevated ozone and rising temperature are both factors in climate change, but they are difficult to study in combination due to exposure system requirements. We developed and deployed an air exclusion exposure system to treat soybean [Glycine max (L.) Merr.] cultivar “Jake” with season-long combinations of sub-ambient ozone (18 ppb, 12-hour mean), elevated ozone (66 ppb, 12-hour mean), and elevated temperature (+3.5 degrees Celsius daytime, +2.4 degrees Celsius nighttime) in irrigated field plots. Warming caused a shift in biomass partitioning from reproductive tissues into stems and petioles at mid-season that resulted in a significant 25% reduction in final seed yield and a significant reduction in harvest index. The elevated ozone treatment delayed mid-season biomass production, and final seed yield was reduced by a non-significant 2%. However, there were significant underlying effects of elevated ozone on seed production. The non-significant impact of ozone on seed yield of cultivar “Jake” resulted from significant increases in pod number (+16%) and seed number (+18%) that were offset by a significant reduction in seed size (-16%). No evidence of significant warming*ozone interactions was found in biomass or seed yield responses. In general, significant impacts of the individual warming or ozone treatments were found to be additive.