Radiation Use Efficiency: Key to Improving Crop Performance.

Radiation use efficiency describes the ability of a plant community to intercept light and convert that light into biomass or grain. It is not as widely recognized or used compared to water use efficiency or nitrogen use efficiency, radiation use efficiency provides a direct comparison between the ability of a plant canopy to capture solar radiation and effectively utilize that light to drive the photosynthetic process. Observations of solar radiation in plant canopies are achievable with the use of remote sensing tools and allow for a screening of different crop production systems. In corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) canopies we have combined different indices to describe the patterns of light interception during the vegetative growth phase to evaluate the amount of light intercepted by the canopy at the point of maximum leaf area development with the indices more sensitive to the senescence phase to evaluate the ability of the plant canopy to continue to intercept light. These combinations of methods allow for a rigorous approach to quantifying differences among management systems and how these tools can be applied to evaluate how efficiently light is utilized by plant canopies.