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Precision Ag, Technology & DiagnosticsYield Monitoring Systems
A yield monitor records how much crop comes off each part of a field as you harvest. The numbers are only as good as the calibration behind them, so treat setup as part of the harvest, not a chore.
Key points
- Yield monitors combine flow, speed, width, and position.
- Calibrate at season start and whenever conditions change.
- Bad edges and wrong header widths are common error sources.
- Use maps to raise questions, then check with soil tests and field notes.
- Back up data and understand who owns it.
What does a yield monitor measure?
A yield monitor combines three kinds of information: how much crop is moving through the machine, how fast you are traveling and how wide a swath you are cutting, and where you are in the field. From these it estimates output per acre at each point.
Grain systems often use sensors in the clean grain path plus a moisture sensor. Hay and forage systems may weigh bales or measure flow in the chopper or baler. The details differ, so read the manual for your machine.
The same idea applies to hay. A baler that records bale weight or moisture by field gives you a running picture of which fields are productive and which cost more than they return, even if you never make a full map.
Why does calibration matter so much?
Without calibration, a monitor produces pretty maps with wrong numbers. Calibration ties the sensor reading to a real weight, usually by weighing loads on a scale and adjusting the monitor to match.
Most manufacturers recommend calibrating at the start of the season and when crop, moisture or flow rate changes a lot. Follow your manual for the exact method, and keep a log of when you did it.
What should you do before harvest starts?
Run through a checklist so you do not discover problems halfway across the best field.
Set aside an hour during your normal pre-season service.
Moisture measurement deserves attention. Moisture sensors drift and can be thrown off by dirt, so check readings against a trusted handheld or lab test from time to time and note any difference. Treat the first season as a learning season. Calibrate carefully, collect the data, and compare it with what you saw and weighed yourself, such as truckloads, bale counts or scale tickets. The difference between the monitor and the scale is your correction factor, and it tells you how far to trust the maps.
- Clean sensors and check for wear or damage
- Confirm swath width settings match the header or pickup
- Check date, time, and field names on the display
- Inspect wiring and connectors for rodent damage
- Verify the positioning signal and any needed subscription
What causes bad yield data?
Common causes include a sensor out of calibration, wrong header width entered, delays at the start and end of each pass, and turning on or off at the wrong spot. Short passes and point rows add errors that are hard to avoid.
Treat edges and headlands with caution. Many farmers filter or ignore data near field ends and in tight turns when they look at the map afterward.
How can a small farm use yield data?
On a 40-acre hay farm, a weight record per field or per cutting tells you which fields earn their keep. On a grain field, a map can show low spots, compaction, drainage trouble, or fertility differences. It points to questions, not final answers.
Pair the map with soil tests, drainage observations, and notes about planting and weather. Your extension office can help you read patterns without jumping to the wrong conclusion.
Do not read too much into one season. Weather, planting date, and pests change from year to year. Several years of maps give a more reliable picture than a single harvest.
How should you store and share the data?
Export raw files at the end of the season and keep a backup off the machine. Name files clearly with farm, field, crop, and year information. That habit alone saves hours later.
If you share data with an advisor, a landlord, or a cloud service, read the terms first. Know who owns the data, who can see it, and how to delete it. That is part of equipment data security as well.
When do you need a technician?
If a sensor is damaged, the combine or baler wiring harness has faults, or the monitor shows errors that clearing does not fix, the dealer service department can diagnose it. Do not reach into any harvest machine to clean or adjust a sensor while it is running, and lock out the machine as the manual directs.
Keep the operator manual in the cab and write your calibration settings on a label inside the cover. When the dealer asks what you set, you will have the answer.
Sources and further reading
Organization homepages are linked so you can search them for current guidance on this topic.