Standardization of Canopy Reflectance of Peanut (Arachis hypogaea L.) Varieties to Assist in Developing a Yield Prediction Tool.

The use of remote sensing in agriculture has greatly increased over the past decade and this is no exception in peanut. Spectral reflectance can be impacted by numerous factors that influence crop health such as soil type, nutrient deficiency, water stress, etc. Spectral reflectance can also be influenced by factors not related to crop health including canopy color variations among varieties. There are over 10 commercially-available peanut varieties in Georgia with canopy color variations ranging from dark green to light green. This can make it very difficult to develop techniques to analyze aerial imagery for crop health issues that can be used on multiple varieties. The objective of this study was to develop a color standardization protocol to eliminate potential reflectance variation across peanut varieties. For this test, variety trials at the University of Georgia Coastal Plain Experiment Station were utilized. Remote sensing images were acquired throughout the growing season and multiple vegetative indices (VI) were applied to the images. Reflectance was measured using a field spectrometer and plant chlorophyll content was estimated using a SPAD meter in the field for each plot to aid in standardizing varieties. Yields for each plot were then correlated to the average for each VI to determine the method of standardization. The standardization of canopy reflectance of commercial peanut varieties allows for the development of remote sensing techniques.