NEAR INFRARED SPECTROSCOPY – AN ALTERNATIVE TO DETERMINE THE CRUDE FIBER CONTENT OF FORAGES

Abstract

In our days NIR spectroscopy represent a promising alternative to the chemical methods for crude fiber contents of forages. The main objective of this study was to obtain a NIR calibration model for prediction this parameter of forages harvested in June 2009 from hill permanent grassland (Grădinari, Caraş-Severin District). The experimental field was organized in ten experimental trials fertilized organic, mineral, and organo-mineral. The floristic composition of forages from this period was determined gravimetrically. From Poaceae were present Festuca rupicola and Calamagrostis epigejos. Fabaceae family was represented by Trifolium repens and Lathyrus pratensis. From other botanical family: Rosa canina, Filipendula vulgaris, Galium verum and Inula britanica. Like input data for NIR calibration were used the results for this qualitative parameter by chemical method and the reflectance values from 150 NIR spectra for all analysed samples. Partial last square (PLS) regression was used to obtain the “NIR - Total Fiber” model, implemented in Panorama program (version 3, LabCognition, 2009). The statistical parameters (R²=0.80; RMSEC=2.73) and the differences between references and predicted values situated in range 0.03 and 9.24% suggest a medium quality of calibration model, but it is promising to use it to predict the crude fiber contents of forages from grassland in this period of year using higher number of samples for calibration.