The most essential component of precision farming is the yield monitor . a sensor . or
group of sensors . installed on harvesting equipment that dynamically measure spatial yield
variability. Yield maps, which are produced using data from yield monitors, are extremely useful in
providing a visual image to clearly show the variability of yield across a field. In response to the
demand for a reliable and accurate cotton yield monitor, several monitors have recently become
commercially available. We assessed the AgLeader, AgriPlan, FarmScan, and Micro-Trak cotton
yield monitors in southern Georgia for five harvest seasons between 1997 and 2001. During 2001
we also assessed a prototype yield monitor. Each year, three or four yield monitors were mounted
on a cotton harvester and used during harvest of several farmer-owned and managed fields. The
accuracy of each sensor was tested by comparing the weight of each harvested load to data
produced by the yield monitors. Yield maps from each yield monitor were also produced with the
respective software packages and compared. Feature comparisons of each monitor were
included. Each of the cotton yield monitoring systems we assessed have something to offer a
user interested in creating yield maps. All are capable of producing an adequate yield map
provided the system is properly calibrated, operated, and maintained.