For Keith Roberts, 2012 wasn’t the best year for testing new precision farming technology. The drought impacted his corn and soybean fields, near Morral, Ohio, so he wasn’t able to see as much of a yield increase as he was hoping for from variable-rate planting. But he’s still optimistic about its potential.

“We’re definitely going to use it again this season and I expect we’ll see some yield benefit by increasing the populations on the darker soils,” he says. “We typically have three to four different soil types in each field, so we know there is variation.”

Knowing how to read the satellite images is important, says Roberts’ agronomic consultant, Christina Howell, of Sunrise Cooperative, Crestline, Ohio. “In the corner of one of Keith’s fields, we saw a noticeable difference in the crop. After scouting and soil probes, we figured out it was due to soil compaction. While he couldn’t do anything about it last summer, he did some tillage in that part of the field last fall.”

In other cases, images reveal possible nutrient deficiencies. “Tissue tests can confirm them; then the grower can make an in-season application,” she says.

Some differences show up that require investigation, she says. “Then we have to ask if they’ve done some tiling lately or changed an aspect of their crop management.

One farmer had a mysterious strip on his field image where the crop clearly looked different, she recalls. “It turns out a gas line had been laid across that field several years ago and, in the process, different soil types had been unearthed along that strip.”