While you may have recently bought a yield monitor with the hopes of unraveling the secrets of yield variability in no-till fields, be aware of the limitations in yield map accuracy, cautions Tom Doerge, Pioneer precision farming agronomist.

“Yield mapping is only truly valuable if you can turn the information into better management decisions,” says Doerge. “The key to yield map interpretation is to understand more about the causes of yield map variation, and which causes are impacted by crop management.”

The key challenge to effectively use yield maps is to identify the factor(s) exerting the most influence on yield in single season, and if possible, across multiple years.

Proper Presentation

No-tillers can greatly increase a map’s aesthetic appeal, quality and utility by using proper theming. Theming refers to the selection of yield ranges and color schemes to display yield map data. Doerge says the most critical aspects for proper presentation include data aggregation, number of ranges and color schemes.

• Data aggregation is the method used to group the data into yield ranges. There are four main methods of doing this:

1. Equal count—divides the data so each of the data ranges contain approximately the same number of points; however, the width of ranges usually varies.

2. Equal interval—ranges are evenly spaced, but the number of points will vary.

3. Stand deviation—this technique creates ranges above and below the overall mean in units equal to the standard deviation of the entire data set. Additional ranges are assigned until all…