|SALMERON, MONTSERRAT - University Of Arkansas|
|GBUR, ED - University Of Arkansas|
|BOURLAND, FRED - University Of Arkansas|
|BUEHRING, NORMIE - Mississippi State University|
|EARNEST, LARRY - University Of Arkansas|
|FRITSCHI, FELIX - University Of Missouri|
|GOLDEN, BOBBY - Mississippi State University|
|HATHCOAT, DANIEL - Texas A&M University|
|LOFTON, JOSH - Louisana State University|
|MCCLURE, ANGELA - University Of Tennessee|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/26/2015
Publication Date: 2/19/2016
Citation: Salmeron, M., Gbur, E.E., Bourland, F.M., Buehring, N.W., Earnest, L., Fritschi, F.B., Golden, B.R., Hathcoat, D., Lofton, J., McClure, A.T., Vories, E.D., et. al. 2016. Yield response to planting date among soybean maturity groups for irrigated production in the US Midsouth. Crop Science. 56:747-759. doi: 10.2135/cropsci2015.07.0466.
Interpretive Summary: Soybean is a major crop throughout the US and planting date is one of the main factors affecting yield. Environmental conditions in the US Midsouth allow for planting dates from late March through early July; however, complex interactions among planting date and environment make selection of an optimum cultivar difficult. University and ARS scientists collaborated in a three-year study across eight Midsouth locations beginning in 2012 to examine the relationship between yield and planting day for irrigated soybean. Optimum planting dates ranged from March to May and delaying planting from mid May to early June reduced yields, with the rate of yield decline greatest at the southern-most locations. These results have strong implications for cultivar recommendations for irrigated Midsouth soybean and indicate the need to reconsider planting date recommendations. This research will benefit producers by helping them make the best choices regarding cultivar selection.
Technical Abstract: Planting date is one of the main factors affecting soybean (Glycine max L. (Merr.)) yield. Environmental conditions in the US Midsouth allow for planting dates from late March through early July, and maturity groups (MGs) ranging from 3 to 6. However, the complexity of the interaction among planting date, MG, and the environment make the selection of an optimum MG cultivar difficult. A regional 3-yr study, conducted at eight locations with latitudes ranging from 30.6 to 38.9°N, planting dates ranging from late March to early July, and MGs 3 to 6, was used to examine the relationship between relative yield and planting day. The data indicated that yield was dependent on the location and MG choice. There was a quadratic response of relative yield to planting day in six out of the eight locations studied for MG 3 cultivars, and in five locations for MG 4 cultivars. On the other hand, MG 5 and 6 cultivars were more likely to have a negative linear relationship, with a quadratic response in only two out of the eight locations. Optimum planting dates that maximized yield were dependent on the location and MG combination and ranged from March 22 to 17 May. Delaying planting dates from mid May to early June reduced yields by 0.09 to 1.69% per day, with the rate of yield decline being greatest at the southern-most locations. Overall, MG 4 cultivars maximized yield or were not statistically different from the highest yielding MG at most locations and planting dates.