The water soluble carbohydrates (WSC) content of grass and mixed sward is an important factor in the fermentation quality of silage. At present, WSC measurement by anthrone method require time for analysis. In these regard, a quick analysis method of determining WSC using near infrared reflectance spectroscopy (NIRS) was used at precise calibration of the 2nd derivative spectrum of the wavelength region at 1500-1820nm and 2000-2220nm, and the calibration was determined by partial least squares regression. These conditions were determined by 152 forage samples of grass and mixed sward which include legume. As a result, the determination coefficient was 0.956 and standard error of calibration was 0.51. The Evaluation Index was 10.1 (A) and the ratio of standard deviation of reference data in the pre-dicted sample to SEP was 4.5. Using this method, the analysis time per sample was about a minute and with accurate precision.
