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Providing More Tools to Central Plains Growers

Sunday, November 1, 2009
filed under: Research and Development

Rob Aiken is on a mission. That mission is to supply Central Great Plains farmers with more tools.

No, Aiken does not sell wrenches or acetylene torches. He is, in fact, a crops research scientist with Kansas State University’s Northwest Research-Extension Center at Colby. And the tools he’s interested in consist of management information that the region’s farmers can utilize in their pursuit of higher yields, better quality — and, ultimately, more profitability.

Aiken, who arrived at Colby in 1999 following several years with the USDA-ARS at Akron, Colo., works with several crops. In fact, only about 15% of his time is allotted to sunflower. But that 15% encompasses an impressive volume of work. During the past several years, he has been either a principal or co-investigator on sunflower studies covering areas such as:

• Available soil water, canopy development and productivity

• Limited irrigation of sunflower in northwest Kansas

• Crop simulation models in support of sunflower production

• Dryland strip-till production of sunflower

• Sunflower yields as affected by strip till

• Degree days, day length and sunflower development in the Central Plains

• Management of sunflower stem insect pests

• Evaluation of sunflower for resistance to stem and seed pests in the Northern and Central Plains

• Development of host-plant resistance as a strategy to reduce damage from major sunflower insect pests

• Atrazine tolerance/resistance in sunflower isolines

• Sunflower production under various irrigation frequency and timing regimens

One of the first projects that Aiken became involved in following his move to Colby was an intensive cropping study that included a variety of rotational schemes — all the way from a straight wheat/fallow to three-year rotations incorporating corn or grain sorghum in the second year, and canola, soybeans, sunflower or fallow in the third year.

After eight years, sunflower was dropped from the continuous-cropping system study. Why? “It’s no way to treat sunflower,” Aiken states. “There’s not a lot of water in the ground after a corn or sorghum crop. What water was left, sunflower did its best to pull out; but it just dragged down the whole system. That’s not the way to grow sunflower out here, and I didn’t want to be presenting sunflower data [emanating from] something that is not ‘best management practices.’ ”

Weather can be unpredictable in any farming region, but perhaps nowhere more than in the Central Plains. The past several years have graphically underscored that reality. After a drought that lasted for several years, much of the region experienced a very wet spring in 2009.

“In an unpredictable environment, you need to be prepared to manage for all kinds of conditions,” Aiken affirms. “We need to have a lot of different types of production systems; and we need to research them over a long period of time under a good sampling of the range of weather regimes with which we deal.” That’s why he emphasized the rotation study following his arrival at Colby. It also underlies his ongoing emphasis on fine-tuning cropping systems that allow the region’s farmers to produce well across the broadest possible range of weather conditions.

Sunflower fits well in this approach, Aiken affirms, due to its capacity to be productive under a wide range of environments. The crop’s ability to effectively utilize available water is a big advantage in dry seasons — and, for irrigators, in those situations where well capacity is limited.

The crop does take some “heat” for its water-use efficiency, i.e., the charge that sunflower depletes the soil for the succeeding crop. Aiken’s response? “Well, you know it’s going to be aggressive, that it will go after whatever water is in the ground. So put it into a system where you can manage for that.

“Sunflower belongs on dryland, sunflower belongs in wheat stubble. In most years around here, you should probably fallow after sunflower. Then, if we receive good rains, we should be able to have three to five inches of water in the ground — and that’s enough to get a good wheat crop established.

“Wheat/sunflower/fallow is a very feasible sequence here in the Central Plains.”

A big part of Aiken’s sunflower-related work in recent years has centered on host plant resistance to key insect pests — specifically, the sunflower moth and the stem weevil. A desire to avoid these insects commonly prompts growers in the region to plant sunflower in early to mid-June. The result is a shorter growing season and yields that often are lower than what they could have been, had the crop been planted in early May.

For the past six years, Aiken has teamed up with Fargo-based USDA-ARS research entomologist Larry Charlet to screen interspecific crosses, accessions and breeding lines for tolerance or resistance to the sunflower moth and the stem weevil. Consistent pressure from these two insects makes the Colby location especially suitable — and the project has, indeed, identified a number of lines that possess significant tolerance to at least one of these pests.

The goal, of course, is the eventual development and release of germplasm that commercial sunflower breeders can then incorporate into finished hybrids. Once that occurs, sunflower growers will have an important new weapon in their “battle with the bugs.”

“We have a potential 120-day growing season in this area,” Aiken points out. “If we had pest-resistant hybrids that could fill heads over a six- to eight-week period, we’d have tremendous yield potential.” An early May planting date with an insect-resistant hybrid could, he conjectures, even make sunflower competitive with corn under irrigation.

“I want to give farmer tools,” Aiken reiterates. “And I think hybrid seed is the most effective technology transfer mechanism we have. That’s why I tend to work with breeders quite a bit. If I can add value to something the breeders produce — and then deliver to the farmer — that transaction has occurred.”

— Don Lilleboe

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