Feasibility of using near-infrared reflectance spectroscopy for the analysis of compositions of straw silage

Near-infrared reflectance spectroscopy (NIRS) calibrations of chemical composition in 158 straw silage samples were developed by means of partial least-squares (PLS) regression. Results showed that the correlation coefficients of calibration (R-2) were 0.95, 0.90, 0.86, 0.91, 0.86, 0.95 and 0.90 for crude protein, neutral detergent fibre, acid detergent fibre, hemicellulose dry matter, crude ash and acid detergent lignin respectively; the R-2 of pH, lactic acid, acetic acid, propionic acid, butyric acid and ammonia were 0.98, 0.83, 0.85, 0.36, 0.90 and 0.92 respectively. The RPD (SD/SECV) of these parameters were all greater than 2.5 except acetic acid, propionic acid and butyric acid, and the correlation coefficients of validation (R-v(2)) of the parameters were all greater than 0.80 except lactic acid, acetic acid, propionic acid and butyric acid. These results are of great practical importance in rapid evaluation of silage quality.