Soybean planting date is absolutely critical to maximize yield (in most years and environments). Over the past few years, we’ve participated in a North Central Soybean Research Program (NCSRP) funded project with the goal of identifying causes of the “soybean yield gap.” (What factors are reducing soybean yield?) Across the Midwest, planting date was the most consistent management factor that influenced soybean yield.

Several calls last week with pictures of injured and/or diseased soybean seedlings.  For most of these situations we have the following scenario:  PPO herbicides (flumioxazin, sulfentrazone, saflufenacil) included as a component of the preplant burn down, fields planted 7 days later with fungicide treated seed, followed by 1 to 2 weeks of suboptimum growing conditions (between 40 to 50oF) for 2 weeks, and greater than 2” rain.  These conditions are very conducive to both Pythium damping-off and PPO injury. 

Soybean: Last Monday, May 16, air temperatures dropped to high 20s/low 30s causing some freeze injury to soybeans. Soybeans in low areas of the field are most likely to be affected. Plants should be assessed for damage at least five days after suspected injury to inspect for regrowth. If damage occurred above the cotyledons, the plant will likely recover. If damaged occurred below the cotyledons, the plant will not recover. Look for a discolored hypocotyl (the “crook” of the soybean that first emerges from the ground) which indicates that damage occurred below the cotyledons.