Iowa's 2014 corn planting season got off to a colder and slower than normal start during the first half of April. Now the weatherman says things will finally warm up, notes Paul Kassel, Iowa State University Extension field agronomist at Spencer in northwest Iowa.
Last week saw morning lows plummet into the teens and 20-degree range for large portions of the Plains and Midwest. This week the National Weather Service says farmers can expect to see a dramatic warm-up across much of the U.S. and parts of Canada over the next seven to 10 days.
"You can check soil temperatures using the ISU Soil Moisture Network feature of the ISU Mesonet website," says Kassel. "Select the 'soil temperatures' tab under 'Select Variable.' You can select soil temperatures at 4-, 12-, 24- or 50-inch depths. Most farmers are not too concerned about the recent change in the weather. The thought is – and this usually holds true – there never is much fieldwork accomplished before Easter. So we will hope for good weather now, after Easter."
What does late start mean for planting?
"Although planting in Iowa is getting started a little later than farmers prefer, we are still in good shape," says Mark Johnson, ISU Extension field agronomist in central Iowa. "We still aren't past the optimum corn planting window. Farmers need to be patient and not work the ground when the soil at point of tillage implement depth is still wet. Likewise they need to not plant when the soil is still wet in the top 4 inches."
He cites a table from ISU's Corn Planting Guide (PM 1885 available at Extension Online Store).
Recommended planting date windows for Iowa. Based on multiple-location research, Iowa State University.
The optimum corn planting window for any given year varies. It depends on weather, so one year May 15 to 18 may be much better than April 15 to 18, another year April 25 to 30 may be the best time, says Johnson. "The point is, we are still in good shape and should not be inclined to rush to the field with tillage or planting prior to the soil being fit for field work."
Alfalfa stand evaluation
ow is the time to be checking your alfalfa fields and determining if you want to keep the stand for another season or if it is time to tear this one up. There are two main things to determine, says Johnson.
First, are there enough plants or stems and second, are the crowns that are present healthy enough to survive throughout the season? Slice open several crowns from various areas in the field and inspect the condition of the tissue. If it is brown and/or rotting, the plant is pretty much gone. If half or more of the area is brown, the plant probably won't make it through the season. If the whole area is nice and creamy white, it is a healthy plant. Here is a picture of a healthy crown and root Johnson took while evaluating a stand a few years ago.
Determine how many plants are healthy enough and then how many stems per square foot are present. Counting plants used to be the most common method, but with more research, counting stems has appeared to be a better indicator, notes Johnson. "Fifty or more stems per square foot should provide very good forage yields, 40 or more stems from plants with healthy crowns will provide a good hay crop, if there are less than 40 stems per square foot then another crop should be considered."