Determination of Forage Chemical Composition Using Remote Sensing

Traditional forage nutrient analysis from bench-top near-infrared spectroscopy (NIRS) or common laboratory chemical procedures provides accurate, point-based information, but often does not provide it in a timely way to allow changes in forage or animal management. The objective of this study is to determine the feasibility of estimating concentrations of nitrogen, neutral detergent fiber (NDF), and acid detergent fiber (ADF) of live, standing forages using a hand-held hyperspectral spectroradiometer (radiometer), and to compare these estimates to values determined via NIRS and laboratory chemical methods. Calibration equations were developed from canopy reflectance measurements from monocultures of Bermuda grass and then applied to a test data set to predict N, NDF, and ADF. Statistical analyses showed that forage composition estimates from the radiometer were equivalent to those from the NIRS. Such a remote-sensing approach would enable real-time assessment of forage quality, would allow mapping of the nutritional landscape, could be used as a tool to better manage pastures and supplements, and would assist in making harvesting decisions.