ARS | Publication request: Variability of light interception and radiation use efficiency in maize and soybean

Submitted to: Field Crops Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 5, 2010
Publication Date: January 27, 2011
Citation: Singer, J.W., Meek, D.W., Sauer, T.J., Prueger, J.H., Hatfield, J.L. 2011. Variability of light interception and radiation use efficiency in maize and soybean. Field Crops Research. 121(1):147-152.

Interpretive Summary: Variability of light interception at the field-scale is unknown in corn and soybean. Quantifying variability can provide reliable estimates of field-scale processes and reliable methodology. A field study was conducted in 31 ha corn and 23 ha soybean field near Ames, IA to measure variability of light interception and light use efficiency. Light variability in soybean for a single sensor was 4.5% and with six sensors was 1.8% of the cumulative intercepted light. Light variability in corn for a single sensor was 5.3% and with eight sensors was 1.9% of the cumulative intercepted light. Soybean and corn light use efficiency varied by 16% and 25% from the lowest to highest value. Reliable transmitted light and light use efficiency estimates are obtainable at the field-scale in corn and soybean with four and three line quantum sensors. This information will help scientists who measure light use by corn and soybean obtain reliable estimates.

Technical Abstract: Variability of light interception and its derivatives are unknown at the field-scale in corn (Zea mays L.) and soybean [Glyine max (L.) Merr.]. Quantifying variability can provide reliable estimates of field-scale processes and reliable methodology. A field study was conducted during the 2005 growing season in 31 ha corn and 23 ha soybean field rotated annually near Ames, IA to measure variability of cumulatively intercepted photosynthetically active radiation (CI-PAR) and radiation use efficiency (RUE) by deploying eight line quantum sensors in each field. Cumulative mean PAR interception for soybean was 575 MJ m-2 ending on day of the year (DOY) 249 compared with 687 MJ m-2 in corn ending on DOY 244. Soybean standard error (sX) for a single sensor was 4.48% and with six sensors was 1.83% of the final CI-PAR. Corn sX for a single sensor was 5.29% and with eight sensors was 1.87% of the final CI-PAR. Crop biomass was quantified weekly by collecting four 1 m2 samples. Soybean RUE using all sensors was 1.44 ± 0.06 g MJ PAR-1. The highest CI-PAR from a single sensor had RUE of 1.32 and the lowest was 1.55 g MJ PAR-1. Corn RUE using all sensors was 3.35 ± 0.09. The highest CI-PAR from a single sensor had RUE of 2.87 and the lowest was 3.70 g MJ PAR-1. Reliable transmitted PAR and RUE estimates are obtainable at the field-scale in corn and soybean with four and three sensors, respectively, assuming that crop biomass is accurately measured.