There are several methods to measure how much light is intercepted by a canopy in order to determine if water loss is from evaporation or transpiration. There’s the hard & expensive way and then there’s the smart way: the CTR-1. “Virtual” make Ceptometer offers convenient and flexible tools for measuring and analyzing incident and transmitted Photo synthetically Active Radiation (PAR) in Crop and Forest canopies. This is a a non-destructive method to easily and accurately measure Leaf Area Index (LAI). It provides vital information about the penetration of PAR into crops and forest, and is essential in work such as comparative crop studies, for separating out the effects of cultivars and treatment.