The optimal method for measuring fractional PAR (photosynthetically active radiation) is with the LP-80 Ceptometer. It’s a highly accurate way to determine canopy growth and canopy light interception, along with calculating fractional interception and crop coefficient. And because the methodology is automated, it spares you from intensive hand labor, saving you time. Backed by 35 years of research, the LP-80 is one of the most trusted and relied-upon instruments among crop scientists, ecologists