Now that the snow has melted and the days are getting longer, it’s time to get out into the fields to look at how fall seeded small grain crops survived the winter. It’s important to evaluate your winter wheat stands to determine if there are enough plants in the field to maximize yield. The threshold is 12-15 plants per square foot. If you consistently find that the stand throughout the entire field falls below this threshold then you should strongly consider terminating the field and planting a new crop. One important point on stand evaluation: don’t just look at the above ground vegetative plant parts; dig up plants to look at what is below the soil surface. Live plants that should contribute to final yield will have healthy, white roots and crowns. Any feeding damage or signs of root or crown rot will usually cause early plant death. Carefully scout areas that didn’t have a lot of snow cover or had ice sheeting this winter. These conditions increase the likelihood of winter injury. Once you determine that you have an optimal stand, your next step should be a nitrogen application with some sulfur too. Recent data from UW-Extension showed that the ideal time to apply nitrogen to maximize yield is at spring green up. This is contrary to older studies that advised farmers to wait until after tillering for a nitrogen application if they had healthy stands. Be careful about trying to apply nitrogen when it is too wet as the soil compaction will be detrimental to the wheat yield. Instead, fertilize your wheat on cold mornings when the ground is firm or wait until the soil has dried out. Urea can be broadcasted on wheat but avoid broadcasting UAN through a sprayer as this will cause excessive leaf burn. If UAN is your choice, use a stream bar sprayer attachment to get a more direct UAN application.
Finally, I wanted to touch on terminating a rye cover crop. Cereal rye is one of the more winter-hardy small grain crops. Don’t try to cut corners when it comes to getting rid of rye as it will only give you head aches when your next crop is established. Consider spraying rye when it is 4-6 inches tall and the ground is firm enough for a sprayer. An application of glyphosate and a grass herbicide labelled for rye should do an excellent job of controlling the rye. Seven to ten days after the application, you should be able to perform field operations for the next crop in the rotation. Consult an agronomist at WS Ag Center for spring recommendations on fall seeded wheat and rye.
Mark Kendall