Handheld Near-Infrared Spectroscopy for Undried Forage Quality Estimation

Area of Science:

• Agricultural Science
• Analytical Chemistry
• Spectroscopy

Background:

• Accurate in-field forage quality assessment is vital for optimizing animal nutrition and farm management.
• Traditional laboratory analysis of forage quality is time-consuming and costly.
• Portable Near-Infrared Spectroscopy (NIRS) offers a potential solution for rapid, on-site analysis.

Purpose of the Study:

• To evaluate the efficacy of handheld NIRS devices for in-field estimation of key forage quality parameters using undried samples.
• To compare the accuracy of different scanning methods (static, moving, turntable) for handheld NIRS analysis.
• To assess the impact of water content in undried forage on the prediction of various quality metrics.

Main Methods:

• Utilized three handheld NIRS instruments (NeoSpectra, TrinamiX, AgroCares) to analyze 111 undried forage samples from New York silage bunkers.
• Employed static, moving, and turntable scanning techniques to capture spectral data.
• Validated NIRS predictions against laboratory-analyzed forage quality metrics: Crude Protein (CP), aNDF, ADF, ADL, IVTD, and NDFD.

Main Results:

• Dynamic scanning methods (moving and turntable) significantly improved predictive accuracy compared to static scans.
• Crude Protein (CP) and fiber constituents (aNDF, ADF) demonstrated robustness, with minimal water interference affecting prediction accuracy.
• Digestibility metrics (IVTD, NDFD) and Acid Detergent Lignin (ADL) were negatively impacted by water content due to spectral interference at 1400 and 1900 nm.

Conclusions:

• Handheld NIRS devices show promise for rapid, on-site forage quality assessment of undried samples.
• Scanning methodology critically influences prediction accuracy; dynamic methods are recommended.
• Understanding and mitigating water's spectral interference is essential for improving NIRS prediction of certain forage quality parameters.