Effective cutting width is one parameter that a grain yield monitor uses to calculate instantaneous yield.  In general, a constant value is used to estimate this parameter.  Assuming a fixed cutting width can lead to significant yield measurement errors, especially while harvesting point rows near ends and edges of irregularly-shaped fields.  In an effort to account for variation in actual cutting width, University of Tennessee Sensors and Controls Laboratory personnel have been working to design an effective harvest-width sensor. 

Prototypes based on several different technologies have been developed and tested.  Each design has included sensing elements mounted on a platform header's pick-up reel.  Piezoelectric impact sensors, charge-transfer sensors, and optical reflectance sensors have all been evaluated under field conditions.  To date, none of the technologies have shown promise as viable options. 

Because it will simplify interpretation and improve quality of yield maps significantly, an effective harvest width sensor will be of great value to farmers.  Sensors and Controls Laboratory staff will continue to develop and evaluate new approaches to this difficult problem.

Simmons, E.C.  2001.  Real-time swath width sensing for grain combines.  M.S. thesis, The University of Tennessee, Knoxville, Tenn.

John Wilkerson, Ph.D. 
The University of Tennessee
2506 E. J. Chapman Drive
Knoxville, TN  37996-4531
PHONE:  (865) 974-7266
wilkerj@utk.edu