| Summary: | 碩士 === 國立嘉義大學 === 農藝學系研究所 === 102 === Objectives of this study were to establish the calibration model for quick determination of crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), water soluble carbohydrate (WSC), acid detergent lignin (ADL), ash (Ash), phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) of napiergrass (Pennisetum purpureum) by the near infrared reflectance spectroscopy (NIRS) and providing information to prepare feed for rumen animal. The samples of napiergrass were collected from diverse sources, including different variety of napiergrass (cv.TLG1, cv.TLG2, cv.TLG3, cv.TLG4 and cv.TLG5) in different years, cutting stage, growing season, planted area and fertilizers applied. The samples were divided to two parts. One part of the samples were taken for determining CP, ADF, NDF, WSC, ADL, Ash, P, K, Ca and Mg by traditional chemical analysis and the other part was scanned by NIRS. The partial least squares regression (PLSR) was be used to establish the calibration equations. The results showed that the coefficients of determination (R2) between calibration equation and chemical analysis for CP, ADF, NDF, WSC, ADL, Ash, P, K, Ca and Mg of napiergrass were 0.96, 0.91, 0.85, 0.94, 0.76, 0.95, 0.77, 0.89, 0.79 and 0.86, respectively. The standard errors of calibration (SEC) were 0.62, 0.97, 1.48, 0.73, 0.76, 0.77, 0.08, 0.44, 0.02 and 0.03%, respectively. The standard error of cross validation (SECV) were 0.68, 1.01, 1.54, 0.78, 0.81, 0.84, 0.08, 0.47, 0.02 and 0.04%, respectively. The coefficients of cross validation (1-VR) were 0.95, 0.90, 0.84, 0.93, 0.72, 0.94, 0.73, 0.87, 0.75 and 0.82, respectively. The results show that the accuracy of calibration equations on organic compounds of napiergrass, i.e., CP, ADF, NDF and WSC were better than those of mineral elements, i.e., P, K, Ca and Mg. However, the calibration equations of mineral elements, the accuracy of ash and K were better than those of P, Ca and Mg. The calibration equations of NIRS were be test and verified with another 80 new napiergrass samples for determining CP, ADF, NDF, WSC, ADL, Ash, P, K, Ca and Mg. The results showed that the percents of difference between chemical method and NIRS prediction were -2.94, 3.68, -3.91, 6.73, 35.49, -9.44, 23.14, -11.86, 20 and 15.41％, respectively. The correlating coefficient (r) between chemical analysis and NIRS prediction were 0.95, 0.89, 0.90, 0.88, 0.46, 0.80, 0.44, 0.83, 0.51 and 0.68 for determining CP, ADF, NDF, WSC, ADL, Ash, P, K, Ca and Mg respectively. The results showed that the calibration equations of NIRS for predicting the CP, ADF, NDF, WSC, Ash and K of napiergrass could be used to quickly determine those of contents in napiergrass.
The results could be suggested to dairy farmer for preparing feed and breeder for breeding the new forage crops.
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