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Choosing Soybean Varieties for Midsouth Locations

In January 2011, members of the Midsouth Soybean Board (MSSB) met in Dumas Arkansas to plan a strategy for implementing and supporting regional projects that would benefit Midsouth soybean producers. At that meeting, it was decided that the first such project should be a multi-state effort designed to aid producers in selecting the appropriate soybean maturity group (MG) from which to select varieties based on latitude and intended planting date at their location.

This project received joint funding from the USB and MSSB participating states. Dr. Larry Purcell of the University of Arkansas led the project. Its official title became “Effect of Planting Date, Latitude, and Environmental Factors on Choice of Maturity Group in Midsouth Soybean Production”.

Following the completion of 3 years (2012-2014) of field research at 11 Midsouth locations, a resulting data set was used to develop an online decision support tool called SOYMAP (Soybean Maturity, Analysis, and Planning).

This support tool is based on simulations specific for soybeans, and 30-year weather data from the 11 locations (30.6°-38.9°N latitude) used in the study. At each location, simulations were run for weekly planting dates from March until the end of June and for MG’s III to VI in one-half MG increments when planted on either a silt loam or clay soil.

The support tool, when queried, provides a comparison between any two MG’s for a given location, planting date, and soil type. Resulting information includes yield responses, predicted dates of R1, R5, and R8, irrigation requirements, and economic returns.

To provide a guide for using this tool, Drs. Larry Purcell and Michael Popp of the Univ. of Arkansas have posted a SOYMAP TUTORIAL that will provide valuable insight into how to use SOYMAP to choose the soybean MG most likely to provide the greatest economic return at locations within the range of latitudes used in the study.

In addition to the above online tool, publications titled “Soybean Yield Response: Planting Date and Maturity Groups...” have been composed for Arkansas, Mississippi, Missouri, and Tennessee. These publications for the individual states provide the data and supporting documentation to obtain the best estimates for variety/MG choice based on planting date at locations within each state.

Producers are encouraged to use both the SOYMAP tool and the individual state’s guides that have resulted from this regional project when selecting a variety for the intended planting date at their location.

Composed by Larry G. Heatherly, June 2017,