by Mark Parker
Parsons, Kansas —
With this year’s corn and beans mugged by Mother Nature, farmers attending last week’s field day at the East-Central Experiment Field near Ottawa had their sights set on next year.
From glyphosate resistant weed control to evaluating the economics of precision ag technologies, the presentations were geared toward more profitable production in 2013.
K-State’s Kraig Roozeboom couldn’t have had a more timely topic than his discussion of drought tolerant corn hybrids—especially against a backdrop of corn that had received less than a third of its normal rainfall since April.
Noting that current hybrids—Dupont/Pioneer’s Optimum AQUAmax and Syngenta’s Agrisure Artesian—were selected and bred from drought-stressed environments, he said genetically modified (GMO) second generation drought tolerant hybrids are on the way.
Monsanto is expected to have a drought-tolerant GMO hybrid in limited release for the western Corn Belt next year. Syngenta and Dupont/ Pioneer also have GMO hybrids in the pipeline.
Roozeboom emphasized that drought tolerant hybrids don’t automatically perform better than other adapted hybrids because they won’t have a drought “advantage” every year. In the case of good rainfall years, they will hopefully perform no worse than adapted hybrids but are designed to have a yield edge in dry weather.
He stressed, however, that farmers should not expect them to make something from nothing in extreme heat and drought scenarios—“No hy-brid can produce corn with poor pollination or if it burns up before the grain can fill,” he said.
Roozeboom noted that, in K-State testing, a primary advantage of the drought resistant varieties appears to be the ability to perform at higher seeding rates, contributing to increased yields in dry weather situations.
With herbicide resistant waterhemp populations exploding in Kansas in recent years, K-State Weed Scientist Dallas Peterson told growers it’s time to refocus their weed management efforts.
A preemergence herbicide application should be the foundation of glyphosate resistant waterhemp control, he recommended. For corn, Peterson said preemergence options include Atrazine premixes, Lexar/Lumax, Balance Flexx and Verdict. Postemergence options for corn include Callisto, Laudis, Armezon, Impact and Status.
In soybeans, herbicide choices prior to emergence include Prefix, Authority, Valor, Fierce, Intrro, Warrant, Outlook and Verdict.
A more limited list of postemergence options for beans includes Cobra, Flexstar, and Ultra Blazer.
Peterson did caution that rainfall is necessary for activation of the preemergence herbicides and he made sure producers understood that waterhemp should be targeted at a height of four inches or less.
Soybean growers will soon have new weapons for the weed control arsenal, however.
Roundup Ready 2 Xtend Soybeans add dicamba resistance to glyphosate resistance for the ability to use both herbicides on the soybean crop.
Enlist Soybeans combines a 2,4-D resistant gene to stacked traits for glufosinate (Liberty) and glyphosate resistance.
The dicamba and 2,4-D tolerant soybeans, Peterson said, will offer improved control of tough weeds like smartweeds and velvetleaf as well as herbicide resistant weeds like marestail, pigweed and ragweed. Additionally, the new soybeans will enable growers to expand herbicide rate options.
Neither, however, will be a cure-all for weed problems, the weed scientist emphasized. Good stewardship, especially by incorporating preemergence herbicides into weed management, will be necessary to extend the usefulness of the new technologies.
There will also be other management requirements. In the case of the dicamba tolerant soybeans, drift will have to be managed although the new formulation will have lower volatility.
Farmers can also expect some new herbicide chemistry for corn weed control. K-State Agronomist Curtis Thompson outlined some of the new herbicides available.
A new active ingredient coming on the market is pyroxasulfone. It will be marketed by BASF as “Zidua.”
Anthem and Anthem ATZ from FMC is a premix of pyroxasulfone and Cadet with Anthem ATZ also containing atrazine.
Thompson also noted that glyphosate continues to be a key component of postemergence weed control programs in corn despite resistance issues in several species. The chemical, he said, continues to be very active on grasses and several broadleaf species.
A tank mix partner, Thompson said, extends control. Halex GT (premix of Callisto, S-metolachlor and glyphosate) has been effective on waterhemp, he noted, as has three ounces of Callisto with glyphosate.
Laudis and Capreno from Bayer, both of which contain an HPPD inhibitor, have also shown good waterhemp activity in a mix with glyphosate and the HPPD inhibiting BASF herbicides Armezon and AMVAC are also options.
Thompson pointed out that the addition of atrazine to HPPD inhibiting herbicides provides more consistent broadleaf control.
The irony of discussing high yield soybean practices in the depths of a drought was not lost on K-State Agronomist Doug Shoup but the southeast area specialist pointed out that, with a little help from Mother Nature, there are steps farmers can take to maximize yield.
Begin with crop rotation. Yield increases of three to 14 bushels per acre have been attributed to soybeans following a crop other than soybeans.
Variety selection is also important, as is planting date. Earlier planting—when water is not a limiting factor — maximizes node formation and results in quicker canopy cover to reduce evaporation.
In high yield (40-50 bpa) potential conditions, increasing populations to 120,000 plants/acre maximizes yields while 80,000 plants is the target for average yield (30-40 bpa) fields and 70,000 plants is adequate for lower yielding (less than 30 bpa) environments.
Narrow row spacing, Shoup said, generally leads to higher yields with a 2-3 bpa edge to 15-inch rows versus 30s in southeast Kansas.
Shoup noted that phosphorus has the biggest nutrient-driven yield impact on area bean yields. He suggests a soil test level of 20-30 ppm and added that he has seen some yield benefits to providing some phosphorus as a starter even in high test soils.
Soybeans are fairly sensitive to low pH soils, the agronomist pointed out, explaining that even at a pH of 6, potential yield loss has been identified. Optimum pH for soybeans, he said, is 6.5-6.8.
Seed treatments can result in higher yields, especially for early-planted beans, he said, as well as increasing stand. Treatment of pod- and foliar-feeding insects in the R2-R4 period can pay off in higher yields when those pests are present.
Foliar fertilization results have been variable and not particularly effective, Shoup told the farmers, but in high-yield irrigated environments nitrogen application at R3 increases yields.
When it comes down to whether or not there is a payoff for precision ag practices, there’s no one-size-fits-all answer, Fort Hays State University economist Craig Smith told the field day crowd.
The former K-State grad student was involved, however, in developing a Guidance and Section Control Profit Calculator that is available at www.agmanager.info.
Sprayer section control has a quicker payoff in fields where there is a high percentage of acres in headlands and, as a result, more potential for turnaround overlap. Shape of the field and the angle at which the headlands are entered play a role, Smith said, but input savings is generally higher in small, irregularly shaped fields.
Provided there are adequate total acres to get over, the smaller fields of eastern Kansas typically show a better return for section control than the mega-fields of western Kansas where guidance tends to have a faster payoff.
“No two situations are the same but our work (using a basis of 10,000 acres sprayed annually) indicated that section control can be a good investment on even relatively small farms,” Smith said.
Farmers can use the online Guidance and Section Control Profit Calculator to determine if those precision ag technologies would be good investments in their situations.
“All situations are very site-specific and machinery-specific,” Smith concluded. “Determining whether or not these precision ag tools will pay off for you requires an analysis of your individual situation.”£