March 23, 2009
Over the past few years, we've been discussing the need to use a pre plant or pre emerge herbicide ahead of Roundup Ready soybeans or corn. The reason being to reduce the incidence of resistance developing from continued use of glyphosate herbicide. And most producers have followed through on this management practice, finding it saves them time, money and yield.
It's even more critical to follow this management tactic as we have waterhemp resistant to glyphosate herbicide in the area. We also have waterhemp resistant to the diphenyl ether herbicides (cobra, phoenix, blazer, flexstar, etc.) as well. And the waterhemp populations resistant to diphenyl ethers are much more common that those waterhemp populations resistant to glyphosate. So the need to use a pre-emerge herbicide is even more important, because in soybeans, those are the only two herbicide families that can be used post-emerge to control waterhemp.
A number of herbicides are available in soybean to provide pre control of waterhemp, including: valor, authority, intrro, dual, treflan, prowl (and premixes including these products). And the cost of these products will range from approximately $5-$10 per acre. It's the cheapest form of resistance management you can use if glyphosate is the planned second trip.
The use of a pre herbicide ahead of Roundup Ready crops allows you delay the post herbicide trip (glyphosate) because of the weed control offered. However, keep in mind that weeds do compete with crop yield, and follow the guidelines of 4-6 inch size weeds for corn and 6-8 inch size weeds for soybean when making that glyphosate post application. Otherwise, allowing weeds to grow to larger sizes can cost you big bucks, much more than the cost of the herbicide and the application.
Aaron Hager, U of I Extension Weed Science, recently determined the exact cost of delayed post emergent application, based upon soybean price and yield lost due to delayed application. With a 50 bushel yield, and bean prices of $10, just a one day delay in post emerge application will cost you $5 per acre in lost yield. If you delay that application by 5 days, then the weed competition will reduce your soybean yield to the tune of $25 per acre.
March 10, 2009
March 5, 2009
All final versions of the 2009 iFarm and FAST Crop Insurance Tools are available at:
The final versions of the 2009 tools have been updated with the following values for areas with sales closing dates of March 16, 2009.
Final Values for Corn are:
APH indemnity price = $4.00
CRC base price = $4.04
RA base price = $4.04
GRIP base price = $4.04
CRC price factors = 0.944
RA price volatility = 0.370
GRIP price volatility = 0.340
Final Values for Soybeans are:
APH indemnity price = $9.90
CRC base price = $8.80
RA base price = $8.80
GRIP base price = $8.80
CRC price factors = 1.754
RA price volatility = 0.310
GRIP price volatility = 0.310
March 5, 2009
No doubt there are far fewer acres of wheat this year than we've had for a number of years. Complications of wet soil and the late harvest limited the number of acres sown last fall. Because of the late planting, many of the wheat acres were somewhat under developed entering dormancy when compared to normal. There just wasn't enough time between sowing and fall dormancy to get good growth. Hopefully, producers sowed at a heavier rate last fall to compensate for reduced tillering. As each tiller can produce a spike (head), increased tillers lead to increased yield.
Spring weather can also influence tillering. Since wheat is a cool season crop, a sunny and cool early spring can favor tiller development. Nitrogen can also influence tillering. Late winter nitrogen applications on thin stands may increase tillers. Take some stand counts. As a rule of thumb, 70 tillers per square foot is considered adequate for optimal yield.
The U of I has adopted some new nitrogen recommendations for wheat. These are based upon soil organic matter, nitrogen price and wheat price. The first step is to determine the amount of nitrogen a bushel of wheat will "buy". For instance, with urea priced at $400 per ton, the cost per unit of N is about 45 cents per pound. With wheat selling for $4.50 (July cash bid), one bushel of wheat would buy 10 pounds of nitrogen.
Then determine the organic matter level of the soil in which the wheat is growing. Higher soil OM levels can allow you to reduce your N application rates, as the soil will provide nitrogen through mineralization. Based upon the above economic scenario, the recommended N rates for various soil OM levels are as follows:
Soil OM of less than 2%- 120-150 pounds nitrogen
Soil OM of 2-4%- 80-100 pounds of nitrogen
Soil OM of greater than 4%- 50-70 pounds of nitrogen
Care should be taken if applying 120 or more pounds of nitrogen to ensure that overlap doesn't occur. And if attempting to interseed clover, you'll need to reduce the N rate by 25% or so.
March 4, 2009
March 3, 2009