Combine Yield Monitors

Current Yield Monitors n Mass-flow sensor n Volumetric-flow sensor n Conveyor belt load sensor n Trailer load sensor n Torque transducer

Basics of Yield Monitoring n Possible Crops to Monitor –Wheat and other grains –Cotton –Potato and Sugar Beets –Beans –Rice –Specialty Crops < Grapes, Tomatoes, Carrots, etc.

Impulse Yield Sensors John Deere Case Ag Leader Micro Trak

Impulse Flow Meter Force Vectors

Dynamincs of an Impulse Flow Meter

Non-Impulse Yield Sensors Nuclear - Massey Ferguson - Europe High Frequency Radio Waves New Holland - Not marketed

Capacitance Moisture Sensors John Deere Micro Track Ag Leader Case

Yield Mapping Trailer (Sugar Beet Harvest)

Yield Mapping Trailer n Measures change in weight in the trailer while allowing for comparison at different times. n Can be used for any crop that is loaded into a trailer continuously while harvested.

Conveyor Yield Monitor

Corn Silage n The drive shaft of the base unit powering the cutterhead, feedrolls, and front attachment, are instrumented with strain gauge torque transducers. n Cutting power is linearly related to material feedrate. n Material flow can be expressed as: –F r (t)=Y i (t)S p (t)W

Capacitance Moisture Sensors

Sources of Yield Map Error n Unknown swath width n Time lag of grain through combine n GPS error n Multiple paths through combine n Surging of grain through combine n Grain losses n Sensor Calibration

Sources of Impulse Yield Sensor Error n Grain Moisture n Grain Test Weight n Grain Temperature n Grain Cultivar n Grain Species n Contamination –Dirt –Plant oils, sap, etc.

Effect of Lag Time on Combine Yield Measurements P P t t t0t0 Crop Yield Along Swath Actual Grain Yield Yield Monitor Measured Grain Yield Yield

Grain Flow Rate

Comparison on Raw and Filtered Combine Flowrate Data

Smoothing Effect of the Straw Walkers

Combine Yield Monitor and Satellite Estimated Wheat Yield Maps Yield Monitor 26.4 bu/ac Satellite Estimate 28.7 bu/ac

GPS Error in Corn – Loss of Differential Correction Signal Oklahoma Panhandle, 1998

Two Combines in the Field with only One Equipped with GPS Oklahoma Panhandle, 1997

Corn Yield Surface with Krieging Oklahoma Panhandle, 1997

Corn Yield Surface with Krieging Oklahoma Panhandle, 1998

Wheat Yield Under a Center Pivot Irrigation System Oklahoma Panhandle, 1998

Wheat Yield Under a Center Pivot Irrigation System Oklahoma Panhandle, 1997

Wheat Yield Under a Center Pivot Irrigation System Oklahoma Panhandle, 1997

Wheat Yield Under a Center Pivot Irrigation System Oklahoma Panhandle, 1998

Data Misaligned Because of the Lag in the Combine

Error Caused by the Lag in the Combine

Missing Data

English Wheat Field - Single Soil Type

Southwest Iowa Corn Field YieldMoisture

AgLeader Cotton Yield Monitor Developed by John Wilkerson – University of Tennessee

Peanut Yield Monitor University of Georgia

Lime Streaking Yield Map NDVI Map Lime Streaking not evident 5 Class Krieg Courtesy of Tim Sharp Jackson State C.C.

Yield Surface With Lime Streaking NDVI surface With lime streaking 5 Class Krieg Courtesy of Tim Sharp Jackson State C.C.

Fertilizer Streaking 5 Class Krieg Spinner Applicator Yield SurfaceNDVI Surface Courtesy of Tim Sharp Jackson State C.C.

Major Challenge n Correlate NDVI surface data with yield surface data Courtesy of Tim Sharp Jackson State C.C.

Cotman Sample Points Medium Low High Courtesy of Tim Sharp Jackson State C.C.

NDVI 5 Class Surface of Cotton Red is Bad Green is Good Note Image of Surrounding Fields, they were Top-dressed with A spreader buggy By the grower Severe Streaking Courtesy of Tim Sharp Jackson State C.C.

5 Class NDVI with Fertilizer streaking Green, Red, NIR image Composite Courtesy of Tim Sharp Jackson State C.C.