Ark. researcher explores higher soybean yields
FAYETTEVILLE, Ark. (AP) _ A researcher at the University of Arkansas is working to develop soybean yields that can significantly surpass the 2012 average yield of 41 bushels per acre.
Ryan Van Roekel, a doctoral student, used test plots in eastern Arkansas and Fayetteville to try out his yield-enhancing methods. His research was funded by the Arkansas Soybean Promotion Board.
``We have demonstrated with our strip trials that a good variety, planted early, with timely irrigation, adequate fertility, and good pest control can average over 80 bushels per acre and I believe that is a realistic, profitable, and sustainable yield goal for productive soils in eastern Arkansas,'' Van Roekel said.
Going above the 100-bushels-per-acre threshold is probably too expensive and unsustainable, he said.
``In the small plot trial in Fayetteville, we had 12 different varieties and the best one averaged 115 bushels per acre. Six of the 12 averaged over 100 bushels per acre and the lowest one averaged 86 bushels per acre,'' Van Roekel
The plants, which were irrigated, produced those yields in hot, dry summer conditions.
Grower Kip Cullers of southwest Missouri, who has won his state's Soybean Association Yield contest several times since 2006, has produced contest yields of more than 100 bushels per acre. Van Roekel and his PhD. adviser, Professor Larry Purcell, have been working with Cullers on the project.
The researchers have taken physiological measurements from Cullers' farm in an attempt to understand the inner workings of Cullers' top yielding crop.
``Our research in Fayetteville is managed very similar to Mr. Cullers' contest field and we are taking the same measurements and have the same varieties plus some extras,'' Van Roekel said.
In his work this year, Van Roekel planted on April 11, getting the crop in early. He put in the plants in 18-inch narrow rows at 140,000 plants per acre.
He applied 10 tons per acre of poultry litter and incorporated it into the soil. Also, Van Roekel tilled deeply to break the plow pan to allow roots to spread more easily. He took soil samples and amended with fertilizer.
Van Roekel said early planting may be the most important consideration in increasing yields. The plant's primary resource is carbohydrates from photosynthesis, which peaks in late June.
``So if we can get a full canopy and start setting pods by that time, we stand the best chance of setting more pods and increasing yield,'' Van Roekel said. ``Early planting does not directly cost anything extra and if podset can be timed with the longest days of summer we can increase yield for free.''
Growers need to match maturity with planting dates and also choose a variety with the best package of traits to suit the growing environment, he said. Producers will have to cope with the variables of diseases, pests and weeks.
``We had to spray for insects five times,'' Van Roekel said. ``We also applied three preventative fungicides. You can't be giving up any yield to those pests when pursuing maximum yield. The trick for farmers is finding the most profitable balance between potential yield loss and the cost of controlling the pest.''
Van Roekel said 100 bushels per acre can be attained in Arkansas, but the costs could be so high that growers may not be able to make a profit or sustain the necessary conditions. But aiming a little lower, such as 80 bushels per acre is a realistic goal for east Arkansas row crop farmers, he said.
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