By Dave Schwartz
Gold Country Seed Soybean Product Manager/Agronomist

It’s easy to talk about patience, but much more difficult to practice patience.

With all the corn acres being planted this spring, farmers are anxious to begin planting. April was not very cooperative, with snow and often cooler than normal temperatures. I would encourage growers to be patient and wait until soils are fit, before planting corn and soybeans.

Optimum corn yields in Minnesota are achieved when corn is planted early. Around May 1, potential corn yields may begin to decline very slightly, and the same is true for soybeans around May 20.

In mid May, corn yields decline 0.5 percent each day (less than one bushel per acre) when planting is delayed.

The dilemma that farmers face nearly every spring is waiting until fields are fit for tillage and planting. Over the years, I have seen many corn fields that were “mudded in,” due to a rainy forecast or possibly the grower was held up by breakdowns and got behind. Whatever the reason, soils were too wet and the crop suffered all season long.

Under these planting conditions, corn fields through tasseling are uneven, stunted, and yellow. It seems these fields never really recover. I have seen similar symptoms in soybeans. Soils in these situations are compacted 3 to 4 inches below the soil surface to the point where it is difficult for a spade to penetrate. If a spade can’t penetrate the compacted layer, roots will not either.

Fields with high clay content are less forgiving in wet springs than loamy soils, so avoid planting these fields until they are in good condition.

Should rainy weather delay corn and soybean planting, I would recommend using May 25 as the cutoff period for planting full-season corn hybrids. At this time, growers need to switch to hybrids five to seven days earlier in maturity than what is considered full season.

By June 1, growers should move to hybrids 10 to 14 days earlier than full-season hybrids. The cutoff date for soybeans is later than corn. Around June 10, growers need to shift to soybean varieties that are .5 maturity units less than what they consider full season for their area.