Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 10, 2013
Publication Date: August 9, 2013
Citation: Long, D.S., Mccallum, J.D., Scharf, P.A. 2013. Optical-mechanical system for on-combine segregation of wheat by grain protein concentration. Agronomy Journal. 105:1529-1535. Interpretive Summary: Grain quality sensors that are available for combines creates an opportunity for growers to automatically segregate wheat by protein while harvesting. Higher quality grain in certain areas could be segregated from lower quality grain in other areas of a field. We developed a system for segregating wheat by the protein content of grain on the combine while harvesting. An optical sensor scans the grain as it streams into the combine's bulk tank. Information from the sensor is used to compute the protein content of the grain and operate a mechanical diverter valve for diverting the grain into two different bins. After the grain in each bin was manually sampled and tested in the laboratory for protein content, the results showed that it is possible to sense the protein content of the grain on the combine and use this information to route the grain into one of two bins while harvesting. An advantage of this approach is that knowledge of grain protein differences in fields is not required in advance of harvest.
Technical Abstract: Grain segregation by grain protein concentration (GPC) may help growers maximize revenues in markets that offer protein premiums. Our objective was to develop an on-combine system for automatically segregating wheat (Triticum aestivum L.) by GPC during harvest. A multispectral optical sensor scans the grain as it is conveyed by the combine’s grain bin filling auger. Light from the optical probe is transmitted through a fiber optic cable to a spectrometer, which determines the spectral characteristics of the grain. This information is processed by the instrument control software that is programmed to calculate GPC from a chemometric model. The continuous GPC output is simultaneously fed to a binary computer algorithm for triggering a logic circuit and operating a mechanical diverter valve that diverts the grain into either one of two bins. Field tests of the system were conducted during harvest of hard red spring wheat using a Case IH 1470 combine modified with front and rear bins. Front and rear bins were compared in terms of the mean and frequency distribution of the optically sensed GPC. In addition, the grain in each bin was manually sampled and tested in the laboratory for GPC. Results showed that it is possible to use the GPC measured by an optical sensor to effectively control a mechanical diverter valve for routing the grain into one of two bins on a combine. An advantage of this approach is that prior knowledge of harvesting zones is not required.