“The bottom line was that nematicides cost more than the yield gains he could expect by killing the nematodes. That’s the power of information and how you can make an operation more efficient.”

A yield map gives you an understanding of how much variability you have within a field, and whether it’s worth addressing that variability, he says.

“If the map shows you do have yield variability, and you manage it to address that variability, then the yield map at the end of that season or the following seasons will tell you how well you’ve done with your management practices. So it truly is the entrance exam and the final exam,” says Vellidis.

Yield maps also can show dry corners and major leaks in a center pivot irrigation system, he says. “Yield maps should have high resolution so that you can actually see the pivot tracks in fields.”

Vellidis says he encourages growers to go a step further and create “profit” maps from their yield maps.

“The profit maps are a basic tool to help a producer understand where a field is producing revenue, and where a field is causing losses.

“Areas of losses are shown in red on the map and greens show high profits. Areas that are red are net revenue losses in the field. The grower would have been better off by not farming those areas in the field.

“When you look at the budget for the entire field, more money could have been made by not farming those areas. But it’s not always feasible to completely leave out areas in a field.”

When engineers design yield monitors for farm equipment, they always conduct a design analysis to see where on the machine is the best location for a monitor, explains Vellidis.

“It’s clear that the best location for a yield monitor is somewhere in the ducts or somewhere in the basket, because that’s where the clean yield ends up.

“In the late 1990s when people were developing yield monitors, a lot of these studies were done. Several equipments companies researched this, and it turns out that the ducts are the best place to put these sensors.”

There are two types of sensors available on the market, and they all work on the same basic principle, he says.

“There’s the optical sensor, where you put an emitter on one side of a duct and a receiver on the other side of a duct, and you’re transmitting light beams across the duct.

“The light beams are then interrupted by the cotton bolls flowing up through the ducts.

“Some of them that remain on the market include AgLeader, which is compatible with many generations of AgLeader user interfaces.