Crops are maturing rapidly in Iowa this year because of early planting, above- normal accumulation of growing degree units and in some cases moisture-deficient soils---where crops are prematurely shutting down. Corn silage harvest is well underway, especially on the moisture-deficient soil areas. Early soybean harvest will begin in some areas of Iowa in the next two weeks.
A common question this time of year has to do with yield predictions. There are various methods of estimating yield in specific fields – counting ears, rows of kernels and kernels per row for corn and counting beans per pod and pods per plant in soybeans.
For predicting yields across a larger area, a good starting point is the historic county yield averages, says George Cummins, Iowa State University Extension crop specialist at Charles City. Average county corn yields in his area have been up in three of the last four years with 2003 being the exception. The year 2005 was the best soybean crop ever and 2003 was the lowest in the last 10 years.
Comparing yields in 2006 to 2003
There are some similarities and some differences between 2006 and 2003, he notes. Crop potential as of August 1 both years was good and farmers were optimistic. By Labor Day of 2003 the hot, dry weather had reduced corn yields and the weather, aphid numbers and charcoal rot had reduced county average soybean yields by 40%.
"In 2006 we've had variable rainfall across the area," he says. "In some areas yields will be very good – in other areas the crop yields will reflect the stresses. The consensus coffee shop predictions I'm hearing are that average county yields in our area of northern Iowa will be off 10% to 15% from the 2005 yield figures for corn and beans. I'm anxious to see what the scales tell us."
Would you grow industrial hemp?
Gleaning farm newspapers in recent weeks, Cummins came across several topics, which may have Iowa implications.
Industrial hemp. Value-added groups have identified industrial hemp as an alternative crop with potential biomass and fiber uses. It was also suggested that hemp be grown as part of a manure management plan because of this crop's elevated P and K nutrient removal.
Efforts in the past to get the necessary permits to grow industrial hemp, even for research purposes, have proven futile. Industrial hemp contains only trace amounts of THC, the chemical in marijuana. The California Senate has approved a bill that would allow farmers to grow industrial hemp. This is the first step to legalize its production in that state.
ISU's Northern Research Farm. Iowa State University's Northern Research Farm at Kanawha was established with the encouragement, assistance and support of the sugar beet industry in north Iowa. Preparing for the farm's 75th anniversary celebration on September 10, "we have learned a lot about the industry," says Cummins.
There are acreage quotas to manage supplies and generous subsidies to maintain the price of sugar above world price levels. Preliminary yield tests indicate a record crop in Minnesota and North Dakota this year, larger than can be safely processed by the end of May 2007. Growers have developed a plan to destroy up to 10% of their sugar beet acreage if the record harvest materializes.
Big interest in ethanol production. There is tremendous interest in ethanol production and renewable fuels. Registrations for ISU's BioEconomy Conference last week had to be limited. Such a large number of people wanted to sign up and the meeting place on the Ames campus couldn't hold them all. A local farm manager describes the impact of increasing ethanol production capacity and corn demand on land prices as "ethanol euphoria".
Bob Wisner, ISU Extension economist has developed models of the effects of ethanol production on corn prices, livestock feeders, industrial users and export markets. Mike Duffy, ISU Extension farm management specialist, has used crop rotation data from the northern (Kanawha) and northeast (Nashua) research farms to predict the market price where farmers can profitably justify using a corn-on-corn rotation.
Brazil produces ethanol from sugarcane and is self-sufficient in liquid fuels (4 billion gallons produced annually). The U.S. annually produces 4 billon gallons of ethanol and that is expected to rise to 7.5 billion gallons by 2012. The U.S. uses 140 billion gallons of gasoline per year. Increasing ethanol production will not resolve our dependence on foreign oil.
Worms in corn ears in late August. ISU crop specialists are getting frequent calls about "worms in my corn ears". Is it a corn borer? An earworm? A western bean cutworm? The ISU Entomology Department has an insect gallery that is useful in identifying these and other common insect pests. Go to www.ent.iastate.edu/imagegal/ and click on the icon for "Butterflies and moths." Scroll down the menu to the particular pest you wish to identify.
How much nitrogen should you apply? Finetuning your N application rates has economic and environmental implications. The fall stalk nitrate test (FSNT) has been a useful tool to determine optimum application rates. It can tell you whether or not you applied too little, too much or just the right amount this year.
Stalk samples are taken shortly after black layer (physiological maturity) for this test. Information about the sampling process, where to send your samples and how to evaluate the test results are included in ISU Extension publication PM 1584, "Cornstalk Testing to Evaluate N Management." It's available at county Extension offices or at www.extension.iastate.edu and click on "Publications".