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Title: LABORATORY TEST STAND FOR COMBINE GRAIN YIELD MONITORS

Author
item ARSLAN, SELCUK - IOWA STATE UNIVERSITY
item Colvin, Thomas

Submitted to: Transactions of the ASAE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/23/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Grain yield measurement is considered important because it gives the necessary information to construct yield maps across fields. Yield maps are useful in determining how agricultural inputs (such as seeds and fertilizers) should be applied locally to achieve economical crop production that is environmentally safe. Yield monitors are used to determine the amount of grain produced locally within a field. The objective of this study was to design and build a laboratory test stand to compare the performance of a commercial yield monitor to an electronic scale using simulated grain flow through a combine. The grain flow rates were measured under various operating conditions with the yield monitor as well as with an electronic scale mounted on the same test stand. Initial tests showed that the grain yield can be measured accurately with the yield monitor if the grain flow rates are relatively high. If, however, grain flow rate decreases, the accuracy of the yield monitor decreases. Understanding the limitations of grain yield monitors will help to improve their accuracy and application to precision farming technology.

Technical Abstract: A laboratory test stand was constructed to compare the response of a yield monitor to an electronic scale. The clean grain auger, clean grain elevator, and the grain bin filling auger from a John Deere 4420 combine were used to simulate the grain (corn) flow in the laboratory. Strong correlation was found between the yield monitor and the electronic scale with R**2=0.99 following the recalibration of the yield monitor under laboratory conditions. Duration of each test run and the range of flow rates incorporated into the calibration procedure seemed to be significant factors in obtaining a good accuracy for the yield monitor. Longer runs and high grain flow rates enhanced the agreement between the electronic scale and the yield monitor. Interest in the accuracy and the reliability of the yield monitors was the driving force behind the development of this test stand. Application of these results will improve the accuracy of grain yield monitors.