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Influence of Grind and Gravimetric Technique on Dry Matter Determination of Forages Intended for Analysis by near Infrared Reflectance Spectroscopy 1
Author(s) -
Windham W. R.
Publication year - 1987
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1987.0011183x002700040033x
Subject(s) - grind , dry matter , forage , near infrared reflectance spectroscopy , cyclone (programming language) , gravimetric analysis , zoology , significant difference , chemical composition , environmental science , analytical chemistry (journal) , chemistry , pulp and paper industry , materials science , grinding , near infrared spectroscopy , mathematics , chromatography , botany , biology , physics , metallurgy , optics , statistics , organic chemistry , field programmable gate array , computer science , computer hardware , engineering
Accurate chemical analysis of calibration samples is critical for successful analysis of forage by near infrared reflectance spectroscopy (NIRS). An important component of accurate chemical analysis is dry matter (DM) determination. Variability in DM determination will produce inaccuratestimates of not only DM, but all chemical components when expressed on a DM basis. An additional factor that may influence the accuracy of DM determination of forages intended for analysis by NIRS is Udy cyclone grinding. The objectives of this study were to determine the difference in DM values and precision of the estimate due to hot weighing without desiccation or cool weighing with Drierite (Hammond Drierite Co., Xenia, OH) desiccation, and the effect of regrinding Wiley milled samples through the cyclone mill on DM estimates during sample preparation for NIRS analysis. Fifty forage samples that had been preserved by either oven drying, freeze drying, or sun‐caring were used in the study. The samples were Wiley milled (1 mm) and Udy cyclone milled (1 mm), and analyzed for DM by drying at 105°C for 24 There was no difference ( P > 0.05) in DM values due to the hot vs. desiccator method. However, milling method caused variation in DM values (P < 0.001) and was dependent on the Wiley mill DM prior to cyclone regrinding (i.e., Wiley mill DM < cyclone regrind ( P 0.001)). The DM values from cyclone regrinding were 9.0, 4.1, and 0.75% greater than the Wiley milled material in the 750 to 800, 800 to 900, and 900 to 950 g kg ‐1 range, respectively. The choice of gravimetric techniques in DM determinations is dependent on preference and suitability to laboratory protocol. Analysis of DM by NIRS on cyclone milled material and validation with Wiley milled DM laboratory values resulted in large negative bias and poor standard error of analysis.