It was another wet, rainy and cold weekend in North Central Iowa, and it looks to be another wet week ahead. There is about a 50% chance of rain every day in the 5-day forecast, so chances are we won’t get back in the field any time soon. The good news, however, is that this week’s rains looks like it will be warmer than the icy cold rains we received last week.
Time is also on our side. There’s no need to worry about the dates on the calendar and feel pressed for time to achieve those optimal soybean yields. For most of Iowa, I’ve always considered the optimal soybean planting dates as the last week of April to mid-May. That means farmers normally will not lose yield if they wait until May 15th to plant soybeans. Plus, that extra time will give soil temperatures a chance to warm up again.
Cooler soils tend to bring out the worst in Sudden Death Syndrome (SDS) as early-planted soybean fields are historically more prone to it. There is also some evidence that early planted soybeans are also more prone to iron deficiency chlorosis (IDC). To lessen the risk of IDC symptoms, delay planting soybeans by a week to 10 days on soils with a high PH or with high levels of salts. Years of experience has proven the later you plant soybeans on some of these tougher soils, the better root system these plants will develop. Better root systems will help ward off some of these diseases.
Bottom line: you will likely be better off waiting until conditions improve before planting. Continue to work your crop plan; be vigilant about planting each hybrid and variety in the field where it was intended. (Yes, there is still time to plant corn without worry about switching maturities or switching from corn to soybeans.)
There’s a chance that many farmers will go straight from planting corn to soybeans this year. But given the field conditions, no one should even consider planting soybeans now. Current soil and weather conditions are marginal for planting soybean – at best!