Assessment of Arkansas Soybean Yield Contest Results
For several years, Arkansas has been conducting an annual soybean yield contest called “Grow for the Green”. The premise for establishing the contest was that yield contest data can provide useful information about how to achieve maximum soybean yields in the region.
In an article titled “Physiological Plant Response Differences among High- and Average-Yield Soybean Areas in Arkansas” (Crop, Forage, and Turfgrass Mgmt., Jan. 29, 2018), authors T.C. Adams et al. published results from their assessment of results from the 2015 Arkansas Soybean Yield Contest. The premise of their study was that evaluating producers’ fields that produce high soybean yields in Arkansas might provide relevant information that can be used by other producers who are striving to achieve greater yields.
The following points are gleaned from the above article.
• The authors assessed differences/correlations between plant and seed properties of high- (HY) and average-yield (AY) areas, and evaluated relationships among plant properties and yield from contest entries across seven designated regions of the state to determine which plant and soil properties are most related to high yields.
• Producers with a field entered in the 2015 yield contest (HY area) as well as an average-yielding area (AY area) within the same field or in an adjacent field with the same soil type were identified for the evaluation of yields.
• Varieties in all plantings were in the 4.5-4.9 maturity group range, and planting day of year (PDOY) was the same or similar for the HY and AY areas within each region.
• Soil surface texture was silt loam (6 regions) or fine sandy loam (1 region).
• HY areas outyielded AY areas in all 7 regions by an average of 19% (88.3 vs. 74.4 bu/acre).
• In the four regions where plantings were made on May 1 or earlier, HY areas produced an average 23% more yield than AY areas (104.0 vs. 84.4 bu/acre).
• In the three regions where plantings were made in the first half of June, HY areas produced an average 10% more yield than AY areas (67.3 vs. 61.1 bu/acre).
• Across regions, Boron (B) concentration in seed from HY areas was 10% greater than B concentration in seed from AY areas. The authors concluded that this likely indicates a need for careful management of soil B.
• Concentrations of N, P, K, Ca, Mg, S, Na, Fe, Mn, Zn, and Cu in mature seed from HY and AY areas were not different. The authors concluded that this indicates that micronutrient fertilization is likely not required for high-yield soybeans.
• Yield was negatively and significantly correlated (-0.62) with PDOY, which further validates the importance of early planting to achieve high soybean yields in the Midsouth.
Results from this evaluation of yields from the 2015 Arkansas Soybean Yield Contest lead to the following conclusions.
• Early planting of soybeans in the Midsouth is an important factor for achieving high yields.
• Micronutrient fertilization is likely not required for high-yield soybeans in the Midsouth.
• Yield contest data can provide useful information regarding the achievement of maximum crop yields. However, producers should carefully evaluate the additional costs associated with inputs that may be required to achieve ultra-high yields such as those cited in this study to ensure that these higher yields are more profitable.
• Producers are encouraged to use commodity price data to determine if the yield (and thus economic) penalty such at that cited in this study from late planting of soybeans (comparable to soybeans planted behind wheat–i.e. doublecropping) is supplanted by income from a crop preceding soybeans that will result in this late planting.
Composed by Larry G. Heatherly, Sept. 2018, larryheatherly@bellsouth.net