By Dan Martens, University of Minnesota Extension
On March 20-21, I attended a meeting at the University of Minnesota for Extension staff who work with field crops. Minnesota Extension Climatologist Mark Seeley offered some discussion about current weather trends and prospects for the 2012 growing season. Here are some key points, Mark made.
The current trend of warmer than normal temperature and an early spring is likely to continue without slowing down much. The March 15 seasonal weather outlook listed April as likely to be warmer than normal with no particular odds for being wetter or drier. From May through September, at this point there is no particular indication of being wetter or drier or hotter or cooler.
The new-30 year normal now is based on weather data from 1981 through 2010. The “normals” are generally warmer now than they were for the 1971 to 2000 period. So we are really talking about being warmer than a warmer normal.
Soil moisture deficits through a lot of Minnesota, particularly the southern third of Minnesota are significant. A good share of the moisture in the top 60 inches is below 36 inches. We are picking up some moisture in the top soil now. There’s a gap in the middle.
For many areas in Minnesota, it would take 6.5 inches or more of rain to bring the soil profile to a “normal” spring condition.
In recent years, we have gotten more of our rain in thunderstorms where some smaller areas get more rain and larger areas get less.
Where soil moisture is deficient, that means it’s pretty likely that somewhere in Minnesota the crop will be hurting for lack of moisture. We can tell where that would be.
In every year from 2005-2011 some part of Minnesota was in a severe drought condition. During at least one of those years someplace else in Minnesota has severe flooding during the growing season.
The current weather extremes are a “singular” event. That means they are so far out of the norm that what we are seeing doesn’t mean much related to trends.
For previous years where conditions were similar in the middle of March to what they are like now, the years 1974, 1976 and 1988 got worse as the year unfolded. The years 1964, 1968, 1977 and 1984 got better. Further back in history, 1910 is noted for being a terrible drought year with serious wildfires. Milan, between Appleton and Montevideo, reported 8 inches of precipitation in all of 1910.
Early spring’s effects If things continue to unfold, we will be planting crops earlier. Weeds might start to germinate before we are ready to plant some crops. Some insect problems might develop on an earlier schedule.
In some years, it might not be until the first week of May before we fully evaluate alfalfa fields. We should be able to evaluate fields earlier this year. Alfalfa can still get to be 6 inches tall or so before we see how durable it is.
Planting small grains.
In our campus discussion, our small grain specialists agreed that with current weather trends, when fields are dry enough to prepare seedbeds and plant effectively, we might as well be planting. Small grains are more tolerant of cooler weather conditions and any light frost that might occur.
Some small grain has been planted in Minnesota. The growing point (crown) is about an inch below the ground until about the 5-leaf stage. The crown can handle temperatures down to 28 degrees and sometimes even short periods as low as 22. It will take colder air temperatures to get temperatures this cold at the crown.
Current weather trends don’t mean we couldn’t see a slice of cold air take an overnight low down to 20 degrees or even 10. Thinking about the weather, like a lot of other things, means thinking about the odds. When the snow is gone, the fields are bare, and the soil warms – arctic air will have a more limited cooling effect.
Crop insurance dates
There is a crop insurance planting date that means planting before this date means you won’t have coverage that pays toward replanting. Small grain is less expensive to replant and this might not be considered very significant for small grains.
Corn is much more expensive to replant and the crop insurance planting date for corn should be given much more consideration. Check with your crop insurance rep to know where you’re at with these decisions and consider what this risk means to you.