THE RELATIONSHIP BETWEEN RED EDGE AND CHLOROPHYLL CONCENTRATION IN THE BROADBALK WINTER-WHEAT EXPERIMENT AT ROTHAMSTED

The concentration of chlorophyll in a crop can be related to both the position of the red edge in a reflectance spectrum and the yield of that crop. The use of a remotely-sensed red edge to estimate yield is dependent upon a well-understood relationship between chlorophyll concentration and yield and a poorly understood relationship between red edge and chlorophyll concentration. To determine the form of the relationship between red edge and chlorophyll concentration a field experiment was undertaken using a wheat crop with an exceptionally large range of chlorophyll concentrations. The non-linear form of the relationship between red edge and chlorophyll concentration meant that estimates of red edge could be used to estimate chlorophyll concentration up to 0.5 mg g-1 and thereby yield up to 6t ha-1.