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Measuring Grain Protein Concentration with In‐line Near Infrared Reflectance Spectroscopy
Author(s) -
Long D. S.,
Engel R. E.,
Siemens M. C.
Publication year - 2008
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj2007.0052
Subject(s) - near infrared reflectance spectroscopy , combine harvester , environmental science , near infrared spectroscopy , calibration , analytical chemistry (journal) , threshing , spectrometer , chemistry , agronomy , remote sensing , optics , mathematics , chromatography , biology , botany , geology , physics , statistics
The advent of near infrared (NIR) on‐combine sensors gives growers the opportunity to measure the grain protein concentration of wheat ( Triticum aestivum L.) during harvest. A study consisting of three sequential experiments (laboratory bench, combine test stand, and field) was conducted to evaluate the performance of an in‐line, NIR reflectance spectrometer, referred to as the ProSpectra Grain Analyzer, possessing a factory calibration model. In the laboratory bench experiment, the instrument was mounted to a circulating impeller apparatus designed to simulate a moving stream of grain. The ProSpectra performed well on a validation set of 231 grain samples of soft white winter wheat and explained a high level of protein variability ( R 2 = 0.91, SEP = 3.1 g kg −1 ) with a slope near unity. In the second experiment, the sensor was installed on a combine test stand constructed from the cross and exit augers, and clean grain elevator of a combine, to create the grain flow conditions found on a combine. Predicted protein was highly correlated ( R 2 = 0.93, SEP = 4.5 g kg −1 ) with reference protein of nine large (14‐kg) wheat samples. During the third experiment, the instrument was placed on the exit auger of a Case IH 1470 combine for the harvest of a 17‐ha winter wheat field. Prospectra protein predictions correlated well with reference protein measurements ( R 2 = 0.94, SEP = 3.1 g kg −1 ). This study demonstrated the feasibility of using in‐line NIR reflectance spectroscopy to rapidly (0.5 Hz measurement rate) and accurately (SEP < 5.0 g g −1 ) measure wheat protein in a moving grain stream.