"PREDICTION OF LEAF/STEM RATIO USING NEAR-INFRARED REFLECTANCE SPECTROS" by Alexander J. Smart, Walter H. Schacht et al.

Agronomy and Horticulture, Department of

 

Document Type

Article

Date of this Version

February 2004

Comments

Published in Agron. J. 96:316–318 (2004). Copyright American Society of Agronomy. Used by permission.

Abstract

Leaf/stem ratio of grass stands is an important factor affecting diet selection, quality, and forage intake. Determination of leaf/stem ratio involves a labor-intensive process of hand separating leaf and stem fractions. Our objectives in this study were to evaluate leaf/stem ratio prediction using near-infrared reflectance spectroscopy (NIRS) in monocultures of big bluestem (Andropogon gerardii Vitman), switch- grass (Panicum virgatum L.), intermediate wheatgrass [Thinopyrum intermedian (Host) Barkw. & D.R. Dewey], and smooth bromegrass (Bromus inermis Leyss.). Samples of each species were hand-clipped from monocultures at four locations throughout Nebraska in the 1997 and 1998 growing seasons. Ground samples were scanned by a Per- storp model 6500 near-infrared scanning monochromator. Calibration equations were developed using CENTER and SELECT procedures. Near-infrared reflectance spectroscopy estimated leaf/stem ratio in monocultures of big bluestem, switchgrass, intermediate wheatgrass, and smooth bromegrass with a coefficient of determination (r2) 0.73, 0.96, 0.75, and 0.84, respectively. Near-infrared reflectance spectroscopy was a rapid means of estimating leaf/stem ratio in these grasses.

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