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Corn growers are concerned about the amount of fall-applied nitrogen that might have been lost through the winter and how this might change nitrogen management this spring.
The first question that needs to be asked on nitrogen management is simple says University of Illinois Extension Agronomist Emerson Nafziger. You need to know how much nitrogen the crop will need, then how much is naturally available, and finally, how much should be applied.
“Our best estimate, and this is a bit of a floppy number, is the crop will take up about a pound of nitrogen for each bushel it produces. About two-thirds of that is going to be in the grain and removed by harvest of the crop. The other third will be in the residue. Some of this will get back into the soil, some won’t”, says Emerson Nafziger.
The amount of nitrogen needed then is about 1 pound for every bushel expected. If the expected yield is 200 bushels to the acre, then it will need 200 pounds of nitrogen.
Pay attention to this part.
Nafziger wrote in an article for the U of I’s pest management bulletin on April 18th that the more productive soils in Illinois contain about 3.5% organic matter. A rule of thumb calculation, read it online in The Bulletin, puts the N from this organic matter at 140 pounds. In some years this is apparently all available to the crop, and in others it isn’t.
The N Rate Calculator, which you may find online, tries to average out the low and high organic N years. N added as fertilizer for corn following soybeans in southern and central Illinois should be about 170 pounds, 20 pounds less in northern Illinois.
As for nitrogen loss, Nafziger has this to say in The Bulletin as it relates to his recent nitrogen treatment studies, “ these results show both the risk of N loss and the benefit from delaying some of the N or using inhibitors may be a little less than we’ve thought. Getting data from another year or two will help paint the picture more fully, but these results give some reason to be confident that the N management systems in common use all have good potential to provide the crop with N. Adding costs by changing N management, for example by making another trip over the field to apply late N, may not provide a positive return compared to applying all of the N in one or two earlier trips.”
Nafziger says the corn crop takes up most of its nitrogen in June.
Ever since USDA released the Prospective Plantings report March 31st, many have been wondering if farmers will decide to switch a few corn acres to soybeans. The higher price of that crop seems to make this more likely.
Farmers told USDA in March they would plant about 82.2 million acres of soybeans this season. This is one percent less than last year, and a million acres or so less than the trade had really expected. Prices have rallied since then and University of Illinois Agricultural Economist Darrel Good thinks that million acres could be back in play, but that it won’t really change much, "I tend to think there will be some modest switching given the price reaction we’ve had since that report was released. Soybeans are considerably stronger than when the survey was done and corn prices are steady to weaker than when farmers were surveyed. I wouldn’t be surprised to see up to a million acres, perhaps, move away from corn to soybeans or perhaps some other crops. Again, a million acres doesn’t alter the supply expectation very much".
However, very much, can result in a pretty good rally. Darrel Good and colleague Scott Irwin at ILLINOIS put together a supply and demand table for this year. They added 800,000 planted acres to soybeans, putting the figure at 83 million even. The two project this could result in a 267 million bushel ending stocks number with an average cash price of $9.45 a bushel for the year. USDA season’s average cash price for soybeans for the 2015 crop is $8.75. It’s important to note that while the ILLINOIS projection uses a larger planted acreage figure, it also includes a much lower average yield. Good says there are two reasons for this.
Quote Summary - Our calculated trend yields for both corn and soybeans would be a little less the USDA. So, we start a little lower than they start. And then we monitor the El Niño episode that tends to be fading pretty quickly right now. This suggests to us an elevated risk of below trend yields this year. We start with a lower trend yield on corn, 166.2, and I would want to fade that three or four bushels in my expectations right now. We’d start at 45.2 bushels on soybeans and fade that bushel or so based on the El Niño.
Actually, the projection is down 1.2 bushels to the acre for a projected nationwide average yield of 44.
University of Illinois 16/17 Soybean Balance Sheet Projection - April 13, 2016
USDA will release its first projection of the current growing season supply and demand tables May 10th. Those numbers most assuredly will not yet update acreage, nor are they likely to include a deviation from trend line based on summer weather predictions.
Univeristy of Illinois Extension Agronomist talks with Todd Gleason about the amount of nitrogen available to the corn plant during the growing season, how that fertilizer faired over the warm wet winter months, when to plant corn, and if it is ok to plant soybeans earlier than normal.