Canopy Light Interception
Plant light interception efficiency is a key determinant of carbon uptake by plants; plant productivity over seasonal time-scales is approximately proportional to intercepted light. Canopy architecture, leaf area, leaf angle distribution, and leaf dispersion are determinants in the light distribution and interception within the canopy. In horticultural crops pruning strategies can optimise tree structure and drive higher productivity and increase plant health and longevity. The measurement of fraction of intercepted PAR (f) is an indicator of a plant’s light use efficiency or its ability to convert sunlight into biomass.
The simple method requires at least one PAR sensor above the canopy to measure direct beam and one or more PAR arrays beneath the canopy. A PAR array is necessary beneath or within a canopy because it samples a larger area and considers sunlight variability caused by the canopy. Plotting f over a growing season against some measure of yield or biomass indicates the light use efficiency of crops.