Torrential downpours the week prior and again over the Memorial Day weekend caused saturated conditions in many parts of the Red River Valley at possibly the worst time for not only for wrapping up spring field work but also for the just seeded crops. Now that the wheat has emerged, bare areas are quickly becoming evident. A quick survey suggests that in many cases the bare areas are in the ditches and the slightly depressed portions of fields. This points to excess water likely being to main culprit of these stand losses. Excess moisture (anytime the soil water content is above field capacity) depletes the soil of oxygen and germinating seed will quickly die in these anaerobic conditions. A clue whether excess water contributed to a poor emergence in the affected areas is to dig up the remnants of the seed. If the seed is firm and the radicle and coleoptile are white and firm, the emergence was only delayed (Photo 1). If the radicle and the coleoptile are soft and discolored and the seed has turned mushy, the young seedling died in the anaerobic conditions as a result of the saturated conditions.
Photo 1 - A sprouted wheat seed If you find the coleoptile and or first leave or crinkled up and etiolated right under soil surface, crusting is the main problem. Breaking the crusts as soon as possible will be crucial for the safe as much as possible of the stand and to avoid reseeding. A rotary hoe is the best tool for breaking a crust. A spring-tooth harrow with the teeth set straight down instead of slanted back can sometimes be used. The circular motion of harrow teeth set in this fashion can be very effective at breaking a crust enough for young seedlings to emerge. A heavy rigid harrow should be avoided as too much soil movement may expose seedling roots. If neither of these tools is available, running over the field with and empty double disc drill or a Brillion or Cambridge roller will also break the crust. Replanting decisions will be difficult as the optimum planting window for wheat has basically closed. If reduced stand is uniform (no big skips or holes), keep stands of 15 plants per square foot. After June 1 in northern Minnesota a replant decision should be to a crop other than wheat or barley since yields are reduced by about 50% when planting after these dates compared to normal planting dates.