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Title: HYPERSPECTRAL IN SITU DETERMINATION OF FORAGE QUALITY

Author
item Starks, Patrick
item Ross, John
item Coleman, Samuel
item Phillips, William

Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 2/15/2002
Publication Date: 2/15/2002
Citation: STARKS, P.J., ROSS, J.D., COLEMAN, S.W., PHILLIPS, W.A. HYPERSPECTRAL IN SITU DETERMINATION OF FORAGE QUALITY. SOCIETY FOR RANGE MANAGEMENT MEETING ABSTRACTS. 2002. p. 51-52.

Interpretive Summary: Abstract Only.

Technical Abstract: Traditional determinations of forage quality are not generally performed in a timely way since a forage sample must be clipped, dried and finely ground before it can ve analyzed in the laboratory via benchtop near-infrared spectroscopy (NIRS). The objective of this research is to determine if hand-held, hyperspectral reflectance measurements can be used to quantify forage quality directly in the field with accuracies similar to that of NIRS. Variably fertilized bermudagrass paddocks were sampled over a three year period using a hand-held radiometer. Grass samples within the radiometer's field of view were clipped, dried, ground, and subjected to laboratory determinations of percent nitrogen (%N), acid detergent fiber (ADF) ad neutral detergent fiber (NDF). Additionally, the ground grass samples were scanned using a benchtop NIRS. Predictions of %N, ADF and NDF via the hand-held radiometer were compared to laboratory measurements, and the coefficient of determination (r-square) and standard error of calibration (SEC) for NDF were 0.80 and 1.392, respectively. For ADF the r-square and SEC were 0.77, 1.151, while for %N they were 0.91 and 0.138, respectively. NIRS predictions of %N, ADF and NDF were also compared to laboratory measurements. R-square and SEC values for NDF were 0.81 and 1.372, for ADF 0.76 and 1.176, and for %N they were 0.91 and 0.138, respectively. The study results indicate that predictions of %N, ADF, and NDF generated from hand-held radiometry compared well to the more traditional benchtop NIRS approach. Accurate forage quality estimates fro hand-held radiometry would enable timely, cost-effective management of grazinglands and the diet quality of free-ranging livestock.