by Danielle Beard
Parsons, Kansas —
During the K-State Extension Agronomy Night held in Independence, Kan., Southeast Area Agronomist Doug Shoup covered a variety of areas during his crop update.
After last summer’s high temperatures and low rainfall, Shoup’s discussion of drought tolerant corn was particularly timely.
The agronomist told producers the ongoing development of hybrids capable of producing grain with less rainfall may accelerate an acreage shift away from grain sorghum and wheat as well as stabilizing non-irrigated corn yields.
Current drought-tolerant releases are Syngenta’s Agrisure Artesian and Optimum AQUAmax from Dupont/Pioneer. Both are traditionally-bred hybrids selected from high drought-stress environments, Shoup said.
Transgenic drought-tolerant hybrids are currently being developed by Monsanto, Dupont and Syngenta.
Shoup said drought-tolerant hybrids may perform better than some hybrids in low-rainfall situations but emphasized they are not drought-proof.
He suggested that growers compare drought-tolerant hybrids with their best current hybrids.
Shoup noted that corn is the most responsive crop to additional water. Once the minimum water threshold is met, corn will produce about 13 bushels for each additional inch of water.
One of the benefits of drought tolerant corn, Shoup said, is that it may enable growers to plant at higher populations. This would allow the producer to maintain a proper plant population in case of favorable moisture in the summer, yet provide some protection against having too high of a population in a drought year.
Making the most of any corn hybrid demands good fertility and Shoup pointed out that the price gap between urea and UAN, compared to anhydrous ammonia, has narrowed.
The best nitrogen source depends, he said, on how the N will be applied.
Shoup said placing nitrogen four to six inches in the soil, beneath the microbial layer, is the best method regardless of source. Incorporation of some type, he said, reduces the risk of urea volatilization.
The agronomist also outlined the effect of wheat seed treatments.
“I set a trial to evaluate wheat seed treatments in five locations — Independence, Caldwell, Conway Springs, Clearwater and Andale,” he said. “I used two wheat varieties — Everest and Art — and three different wheat seed treatments, untreated, Dividend Extreme and CruiserMaxx.”
Everest dramatically out-yielded Art in all cases. Everest seed treated with Dividend Extreme yielded 3.2 bushels per acre more than untreated seed. A treatment of CruiserMaxx gave a 1.9 bushels per acre advantage.
The seed treatments failed to make a significant yield impact on plantings of Art which yielded roughly 16 bushels less than Everest on average.
“Everest is just a good wheat variety,” Shoup said.
Regarding soybeans, Shoup discussed seed and foliar treatments as a means of limiting disease and insect pressure.
Looking at fungicide and/or fungicide plus insecticide seed treatments across 11 environments, Shoup found a 9 percent population increase from use of a fungicide alone and a 5 percent increase from a combination treatment.
On average, 76 percent of untreated soybean seeds emerged compared to 82 percent of those treated with a fungicide. That, the agronomist noted, could make a difference in seeding rate considerations, allowing growers to plant slightly less seed.
In terms of yield, fungicide-treated soybean seed had a 1.8-bushel per acre advantage across nine environments in 2011 and 2012 studies.
The advantage of foliar treatments was less apparent, Shoup said. When analyzed across 16 different environments, he saw no significant difference in yields between treated and untreated soybeans.
Shoup explained foliar pesticide applications have the best pay-back when insects or disease are present. £