Field conditions are quite variable across Northwest Minnesota this spring. While planting progress has been good to excellent in the southern end of the Red River Valley, areas in the north continue to be quite delayed.

Producers planting soybeans in the first week or two of June should not make significant changes in their management strategies. Most producers should not make changes in variety, seeding rate, or seeding machinery. Strategies that traditionally work best when planting in May, will continue to work well when planting in early June.

Soybean varieties that are well adapted to a producer’s latitude will be delayed in maturity by only one or two days when planted through early June. Cool, short nights in September hasten maturity of late planted soybeans. This reduces the effect of late planting on soybean maturity. Prematurely shifting to early maturity soybean varieties will greatly reduce the yield potential. CAUTION, producers who have purchased seed that is only marginally adapted to their area (e.g. a variety that is ½ maturity group longer than adapted) should now be exchanging seed for varieties that are better adapted.

New, very early commercial soybean varieties have had a reputation for inaccurate maturity date ratings. The best source of information for variety adaptation can be found in the Minnesota Varietal Trials bulletin. The soybean section is available at www.soybeans.umn.edu. Actual 2003 maturity dates are listed for many new commercial and public varieties. Use the maturity date of older/familiar varieties as an index to evaluate the actual maturities of newly released varieties.

Soybean date of planting studies conducted by the University of Minnesota, have shown no additional benefit to narrower rows or higher populations with later planting dates. Although narrow row spacings out-yield wider row spacings, this affect is no greater when planting later. Therefore, producers should not switch planting equipment (e.g. from a row-planter to a drill) when planting soybeans in June. Systems that work well for producers when planting in May, will work well when planting in June.

Seth Naeve Extension Soybean Agronomist