• Energy Research

Abstract Sun-induced chlorophyll fluorescence (SIF) measurements have shown unique potential for quantifying plant physiological stress. However, recent investigations found canopy structure and radiation largely control SIF, and physiological relevance of SIF remains yet to be fully understood. This study aims to evaluate whether the SIF-derived physiological signal improves quantification of crop responses to environmental stresses, by analyzing data at three different spatial scales within the U.S. Corn Belt, i.e. experiment plot, field, and regional scales, where ground-based portable, stationary and space-borne hyperspectral sensing systems are used, respectively. We found that, when controlling for variations in incoming radiation and canopy structure, crop SIF signals can be decomposed into non-physiological (i.e. canopy structure and radiation, 60% ∼ 82%) and physiological information (i.e. physiological SIF yield, ΦF, 17% ∼ 31%), which confirms the contribution of physiological variation to SIF. We further evaluated whether ΦF indicated plant responses under high-temperature and high vapor pressure deficit (VPD) stresses. The plot-scale data showed that ΦF responded to the proxy for physiological stress (partial correlation coefficient, r p= 0.40, p< 0.001) while non-physiological signals of SIF did not respond (p> 0.1). The field-scale ΦF data showed water deficit stress from the comparison between irrigated and rainfed fields, and ΦF was positively correlated with canopy-scale stomatal conductance, a reliable indicator of plant physiological condition (correlation coefficient r= 0.60 and 0.56 for an irrigated and rainfed sites, respectively). The regional-scale data showed ΦF was more strongly correlated spatially with air temperature and VPD (r= 0.23 and 0.39) than SIF (r= 0.11 and 0.34) for the U.S. Corn Belt. The lines of evidence suggested that ΦF reflects crop physiological responses to environmental stresses with greater sensitivity to stress factors than SIF, and the stress quantification capability of ΦF is spatially scalable. Utilizing ΦF for physiological investigations will contribute to improve our understanding of vegetation responses to high-temperature and high-VPD stresses.

This data set is related to a SoyFACE experiment conducted in 2004, 2006, 2007, and 2008 with the soybean cultivars Loda and HS93-4118. The experiment looked at how seed elements were affected by elevated CO2 and yield. ---- The ionomic_data.txt file contains the ionomic data (mg/kg) for the two cultivars. The file contains all six technical replicates for each plot. The cultivar, year, treatment, and the plot from which the samples were collected are given for each entry. ---- The yield_data.txt file contains the yield data for the two cultivars (seed yield in kg/ha, seed yield in bu/a, Protein (%), Oil (%)). The file contains yield data for every plot. The cultivar, year, treatment, and the plot from which the samples were collected are given for each entry. ---- The meteorological_data.txt file contains the meteorological data recorded by a weather station located ~ 3km from the experimental site (Willard Airport Champaign). Data covering the period between May 28 and September 24 were used for 2004; between May 25 and September 24 were used in 2006; between May 23 and September 17 in 2007; and between June 16 and October 24 in 2008. The headers are explained below: -------- year = year -------- month = month -------- day = day -------- max_wind_gust = maximum daily wind gust (miles per hour) -------- xwser = error flag for maximum daily wind gust -------- avg_wind_speed = average daily wind speed(miles per hour) -------- awser = error flag for average daily wind speed -------- avg_wind_dir = average daily wind direction (degrees, clockwise from north) -------- awder = error flag for average daily wind direction -------- sol_rad = total daily solar radiation (mega-Joules per square meter) -------- soler = error flag for total daily solar radiation -------- max_air_temp = daily maximum air temperature (degrees Fahrenheit) -------- xater = error flag for daily maximum air temperature -------- min_air_temp = daily minimum air temperature (degrees Fahrenheit) -------- nater = error flag for daily minimum air temperature -------- avg_air_temp = average daily air temperature (degrees Fahrenheit) -------- aater = error flag for average daily air temperature -------- max_rel_hum = daily maximum relative humidity (percent) -------- xrher = error flag for daily maximum relative humidity -------- min_rel_hum = daily minimum relative humidity (percent) -------- nrher = error flag for daily minimum relative humidity -------- avg_rel_hum = average daily relative humidity (percent) -------- arher = error flag for average daily relative humidity -------- avg_dewpt_temp = average daily dew point temperature (degrees Fahrenheit) -------- adper = error flag for average daily dew point temperature -------- precip = total daily precipitation (inches) -------- pcer = error flag for total daily precipitation -------- pot_evapot = total potential evapotranspiration (inches) -------- pevaper = error flag for total potential evapotranspiration -------- max_soiltemp_4in = daily maximum 4-inch soil temperature under sod (degrees Fahrenheit) -------- xst4er = error flag for daily maximum 4-inch soil temperature under sod -------- min_soiltemp_4in = daily minimum 4-inch soil temperature under sod (degrees Fahrenheit) -------- nst4er = error flag for daily minimum 4-inch soil temperature under sod -------- avg_soiltemp_4in = average daily 4-inch soil temperature under sod (degrees Fahrenheit) -------- ast4er = error flag for error flag for average daily 4-inch soil temperature under sod -------- max_soiltemp_8in = daily maximum 8-inch soil temperature under sod (degrees Fahrenheit) -------- xst8er = error flag for error flag for daily maximum 8-inch soil temperature under sod -------- min_soiltemp_8in = daily minimum 8-inch soil temperature under sod (degrees Fahrenheit) -------- nst8er = error flag for daily minimum 8-inch soil temperature under sod -------- avg_soiltemp_8in = average daily 8-inch soil temperature under sod (degrees Fahrenheit) -------- ast8er = error flag for error flag for average daily 8-inch soil temperature under sod -------- max_soiltemp_4in_bare = daily maximum 4-inch soil temperature under bare soil (degrees Fahrenheit) -------- xst4bareer = error flag for daily maximum 4-inch soil temperature under bare soil -------- min_soiltemp_4in_bare = daily minimum 4-inch soil temperature under bare soil (degrees Fahrenheit) -------- nst4bareer = error flag for daily minimum 4-inch soil temperature under bare soil -------- avg_soiltemp_4in_bare = average daily 4-inch soil temperature under bare soil (degrees Fahrenheit) -------- ast4bareer = error flag for error flag for average daily 4-inch soil temperature under bare soil -------- max_soiltemp_2in_bare = daily maximum 2-inch soil temperature under bare soil (degrees Fahrenheit) -------- xst2bareer = error flag for daily maximum 2-inch soil temperature under bare soil -------- min_soiltemp_2in_bare = daily minimum 2-inch soil temperature under bare soil (degrees Fahrenheit) -------- nst2bareer = error flag for daily minimum 2-inch soil temperature under bare soil -------- avg_soiltemp_2in_bare = average daily 2-inch soil temperature under bare soil (degrees Fahrenheit) -------- ast2bareer = error flag for error flag for average daily 2-inch soil temperature under bare soil -------- site = station name

SUMMARYOzone (O3) is a damaging air pollutant to crops. As one of the most reactive oxidants known, O3 rapidly forms other reactive oxygen species (ROS) once it enters leaves through stomata. Those ROS in turn can cause oxidative stress, reduce photosynthesis, accelerate senescence, and decrease crop yield. To improve and adapt our feed, fuel, and food supply to rising O3 pollution, a number of Free Air Concentration Enrichment (O3‐FACE) facilities have been developed around the world and have studied key staple crops. In this review, we provide an overview of the FACE facilities and highlight some of the lessons learned from the last two decades of research. We discuss the differences between C3 and C4 crop responses to elevated O3, the possible trade‐off between productivity and protection, genetic variation in O3 response within and across species, and how we might leverage this observed variation for crop improvement. We also highlight the need to improve understanding of the interaction between rising O3 pollution and other aspects of climate change, notably drought. Finally, we propose the use of globally modeled O3 data that are available at increasing spatial and temporal resolutions to expand upon the research conducted at the limited number of global O3‐FACE facilities.

This data set is related to the SoyFACE experiments, which are open-air agricultural climate change experiments that have been conducted since 2001. The fumigation experiments take place at the SoyFACE farm and facility in Champaign County, Illinois during the growing season of each year, typically between June and October. - The "SoyFACE Plot Information 2001 to 2021" file contains information about each year of the SoyFACE experiments, including the fumigation treatment type (CO2, O3, or a combination treatment), the crop species, the plots (also referred to as 'rings' and labeled with numbers between 2 and 31) used in each experiment, important experiment dates, and the target concentration levels or 'setpoints' for CO2 and O3 in each experiment. - This data set includes files with minute readings of the fumigation levels ("SoyFACE 1-Minute Fumigation Data Files" folder) from the SoyFACE experiments. The "Soyface 1-Minute Fumigation Data Files" folder contains sub-folders for each year of the experiments, each of which contains sub-folders for each ring used in that year's experiments. This data set also includes hourly data files for the fumigation experiments ("SoyFACE Hourly Fumigation Data Files" folder) created from the 1-minute files, and hourly ambient/weather data files for each year of the experiments ("Hourly Weather and Ambient Data Files" folder). The ambient CO2 and O3 data are collected at SoyFACE, and the weather data are collected from the SURFRAD and WARM weather stations located near the SoyFACE farm. - The "Fumigation Target Percentages" file shows how much of the time the CO2 and O3 fumigation levels are within a 10 or 20 percent margin of the target levels when the fumigation system is turned on. - The "Matlab Files" folder contains custom code (Aspray, E.K.) that was used to clean the "SoyFACE 1-Minute Fumigation Data" files and to generate the "SoyFACE Hourly Fumigation Data" and "Fumigation Target Percentages" files. Code information can be found in "SoyFACE Hourly Fumigation Data Explanation". - Finally, the " * Explanation" files contain information about the column names, units of measurement, and other pertinent information for each data file.