Striving for High Soybean Yield
There are many factors to consider when striving for the highest possible soybean yield. The level of importance of these factors is likely dependent on which soybean-growing region of the U.S. is being highlighted. Below are primary factors to consider when striving for high soybean yields in the midsouthern U.S.
Variety Selection. By now, producers will have selected soybean varieties for planting and likely will have secured seed of those varieties. For midsouthern producers, arguably the most important factor to consider when selecting a variety for a particular planting site is that variety’s nematode- and disease-prevention package. Each producer should know the history of their individual fields and what nematode species and/or disease that may be prevalent or have occurred in that field. Thus, the variety that is selected for planting in a field should have genetic resistance/tolerance to the pest or pests that are known to occur in that field. Click here for links to soybean seed companies where data for each of their varieties can be accessed.
Row Spacing and Seeding Rate. Results from research indicate that soybeans planted at any time should be in rows that are no more than 30 in. apart. Many Midsouth growers use a twin-row planting system where the outside rows in the twin row configuration are 30 in. apart. A seeding rate of no more than 140,000 per acre is adequate. Click here to access a Row Spacing White Paper on this website, and here to access a Seeding Rate White Paper.
Planting Date. Midsouth soybean producers know from experience that planting early–e.g. April 10-20–will provide the best chance of achieving the highest seed yield, especially for plantings that will not be irrigated. This likely means that soybeans will necessarily have to be planted in a stale seedbed with no or minimum preplant tillage to control weeds that are present. Click here to access a White Paper that provides details about the importance of planting date in the midsouthern U.S.
Herbicides for Weed Burndown. To ensure a weed-free seedbed, herbicides in the absence of tillage will have to be used to kill weeds that are present. Producers should thus apply a premix or tank-mix of both burndown and residual herbicides with different MOA’s that will kill all weed species or weed escapes that are present at planting.
Seed Treatment. The preponderance of data from research indicate that applying the appropriate fungicide treatment to soybean planting seed will not result in a yield increase. However, applying the appropriate seed treatment will significantly lower the risk of a failed stand. This is of paramount importance when planting early into soils that may be cool and wet since the early planting window will have closed if replanting is required. Additionally, using an appropriate seed treatment should allow an approximate 10% lower seeding rate to be used. Using a fungicide seed treatment is cheap insurance to ensure an acceptable stand because a planting date later than intended even in late plantings will result in a potentially lower yield. Click here to access a Seed Treatment White Paper that provides information about available seed treatments for soybeans and the pests they control.
Irrigation. A large percentage of soybeans grown in the midsouthern U.S. is irrigated, and this is done to alleviate drought conditions that often occur in the region. Proper scheduling is required to maximize yield and profit from irrigation, and measures that have been shown to conserve the irrigation water supply must be implemented by all irrigators. Click here to access a Soybean Irrigation Guide on this website.
Foliar Applications of Fungicides and Insecticides. Soybeans grown in the midsouthern U.S. often require applications of plant protection materials during reproductive development. The expense of these inputs is significant–thus, choosing varieties with genetic resistance/tolerance to anticipated pests is the cheapest approach. Regrettably, there is little varietal resistance to the prominent insects that plague the crop in the region, so insecticide applications will likely be required to protect a high yield potential and/or ensure maintenance of seed quality. Click here and here to see how disease and insect pests can reduce yield. Click here to access guides that can be used to determine when to apply plant protection materials to the crop, and what products to use to control problem pests.
Adhering to the guidelines outlined above will not guarantee a high soybean yield, but will likely result in the highest yield that is possible given the growing conditions of a particular year.
Composed by Larry G. Heatherly, Feb. 2025, larryh91746@gmail.com