Soybean planting dates and maturity groups: Maximizing yield potential and decreasing risk in Louisiana

Soybean [Glycine max (L.) Merr.] producers in Louisiana began shifting to an early soybean production system (ESPS) in the early 2000s by planting earlier maturing varieties in April and May. Although this shift in planting practices has been supported by research elsewhere beginning in the mid-1990s, there is minimum data focusing on the ESPS across Louisiana. The overall objective of this research was to evaluate the effect of planting date, maturity group (MG), and their combination across a comprehensive set of yield environments in the state of Louisiana to determine the combination of optimum planting date and MG for soybean production. We gathered field data from the 2013 to 2020 seasons originated from three Louisiana State University AgCenter research stations and four seed companies. A total of 428, 926, and 331 observations were analyzed from the Northeast, Central, and Southwest Louisiana regions, respectively. When including all data from across Louisiana, the optimum planting date was April 30. Breaking by regions, the average optimum planting date for the Northeast Louisiana region was April 9. The Central and Southwest results were divided by MG section, and the approximate optimum planting dates were April 15 and May 15, respectively. These results support the ESPS for the Northeast and Central Louisiana regions, but not for the Southwest Louisiana region. Optimizing planting recommendation is a critical component for supporting the development of varieties suitable for the southern production systems of the United States.