When Nile and Nolan Rollene started combining last fall, they switched on a GPS receiver and a yield monitor to record the harvest. As the combine rolled through their central Iowa fields, the Rollenes could tell it was a good year, and the GPS monitor confirmed it. A yield map constructed from the information showed soybean harvest up 5 bu./acre over a year ago and corn yields up also.

The Franklin County growers with about 800 acres of cropland are part of the next wave of buyers after the early adopters who want precision farming equipment. Nolan purchased the monitor and GPS equipment when he started farming with his dad Nile a few years ago. Now the pair are full-fledged precision ag proponents. They pore over the yield maps with their seed sales representative to select the right varieties and hybrids for planting. They also map fertilizer application.

Mainstream monitors

As shown by growers like the Rollenes, precision farming has gone mainstream. “It's been difficult to get firm numbers, but we anticipate that there are over 40,000 yield monitors in use today,” reports Todd Peterson, Pioneer Hi-Bred technologies manager.

USDA figures support Pioneer's estimates. About 40% of the corn harvested for grain went through a yield monitor last fall, according to USDA's Economic Research Service. And 17% of the corn acres planted for grain was field mapped.

“That number is staggering,” Peterson says. “Yield monitors are becoming mainstream. But mapping systems lag behind.”

Growers in Iowa, Illinois, Indiana and southern Minnesota appear to be driving the use of monitors and GPS for mapping fields. These areas are hotbeds of monitor use and yield mapping.

Peterson also notes that the sale of used combines has added to monitor usage. He's heard of many customers who purchased used combines last year with monitors installed. Those customers needed help from Pioneer sales representatives to figure out how to use the monitors.

Pioneer sales representatives and agronomists for years have encouraged customers to use yield monitors and tie them into GPS for mapping. Currently, the Pioneer sales force is promoting a “monitor to mapping” program. Representatives will help growers upgrade a monitor to GPS and mapping capabilities.

Yield comparisons

These efforts are gaining results. Pioneer agronomists work with hundreds of sales reps who do mapping for customers and help create split-planter comparison maps. These maps provide comparisons of different seeds in one field so growers can make better-informed seed purchases.

One successful mapping program is operated by Pioneer field agronomist Mike Tierney of Nora Springs, IA. Tierney combines yield mapping information on a CD from about 100 growers in the central Iowa area, including the Rollenes. Software on the CD allows growers to view about 300 different comparisons ranging from different hybrids and varieties to production practices. For example, a grower can see how fall-applied versus spring-applied anhydrous treatment affected yields in different counties. Other growers may be interested in comparing manure to fertilizer application, different tillage and cultivation methods, and even planter speed and depth.

Tierney started offering this information to a few growers three years ago. He and his wife Sheryl put the information in a binder. Then they started including data from the customers of Pioneer sales representatives in the area. Last year, they moved the information onto a CD because of the growing volume of test results.

Tierney is surprised by how fast growers are adopting yield monitors and GPS technology. “It is going very quickly in Iowa,” he says. “In other parts of the country, there may be some limitations of the land that don't allow easy adaptation.” He estimates that, in the eight-county area by Mason City, IA, more than 400 GPS receivers are being used by growers.

Better seed selection

Split-planter and other yield comparison tests help growers determine what hybrids and varieties work best in certain fields. Tierney recalls one grower who used a split-planter test last year to see what variety would handle a moderate soybean cyst nematode (SCN) problem. The grower compared a SCN variety stacked with Roundup Ready (RR) to a RR variety in the problem field.

The grower was surprised by the split-planter results. Although the SCN/RR stack performed well in the SCN-infested area, the RR variety performed better overall and would produce more total bushels.

“Growers need to look across their entire fields,” Tierney explains. “There are fields where the SCN/RR stack is the right choice. So many growers think that because they have a pocket of SCN in their field, they need a RR variety with an SCN stack. But to make the most money, they really have to ask how big is the SCN area. Even though they won't get very much yield in that spot, the average yield across the whole field may be better with a non-SCN variety.”

Yield mapping changed the varieties and hybrids the Rollenes purchased. Today, they sit down with their Pioneer sales rep Norman Peyton and Tierney to look at yield maps, yield comparisons between different varieties and hybrids, and soil maps. Based on this information, they then determine what seed to purchase. Peyton and Tierney also help them decide what should be planted where.

The Rollenes plant a 50/50 corn-soybean rotation on their farm. Their land sits in an area with dramatically variable soil types that range from highly productive and well-drained soil to very alkaline soil with moderate SCN pressure in spots. In the past, the Rollenes had not considered the soil variability when picking varieties. Instead, they bought high-yielding varieties that produced 60 bu./acre in some areas but dropped drastically in the trouble spots.

Last season Peyton and Tierney suggested soil testing and then helped them rethink their seed choices. They found a variety that is not a SCN variety but tolerates SCN well and is good for alkaline soils. Although the variety did not produce 60-bu. yields, it produced a higher average yield across the entire field. The Rollenes did plant a high-producing variety in the more productive areas of their soybean fields.

“We never picked our beans according to soil type,” Nile says. “A year ago, we sat down with Norm and Mike with a soil map and picked our varieties. The beans never looked this good. So before we ordered any beans for 2003, we sat down with them and discussed what to buy again.”

In the future, growers will face more reasons to develop accurate field maps. Managing what seed should be planted where and what chemicals may be applied to it is becoming more complex. In addition, insect-resistant seed needs specific refuge areas to comply with EPA regulation. Field maps like the ones the Rollenes use will make management of these crops easier, Tierney says. And if the EPA needs to check refuges or applications, the information will be easily retrieved and simple to produce. When that happens, Nile and Nolan will be ready.