By Tim Hoskins, Iowa Farmer Today
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Farmers in Iowa and eight other Midwest states might have lost up $2.3 billion in crop value as a result of nitrogen washed away from the soil due to the wet weather this past summer.
Peter Scharf, University of Missouri Extension nutrient management specialist, used photos from a car trip and aerial photos to estimate yield lost due to lack of nitrogen in the fields.
In Iowa, Missouri, Illinois, Wisconsin, Nebraska, Indiana, Minnesota, Kansas and Kentucky he estimates 460 million bushels of corn yield was lost due to N deficiency. The state breakdowns are:
To arrive at the state figures, Scharf used photos that were collected from a car trip that covered more than 2,000 miles in Kansas, Iowa, Minnesota, Wisconsin, Illinois and Northwest Missouri in the first part of August.
In August, he also hired a pilot who flew into Northeast Iowa through North Central Iowa to Southwest Iowa and back through Northwest Missouri.
Scharf says the photos show the differences in yield. However, in early August it would have been too late to apply fertilizer to correct any problems.
However, the nutrient differences were easy to spot, says Scharf, who has been presenting the information at the recent University of Missouri Crop Management Conference and other meetings.
“There wasn’t a stage you couldn’t see the differences,” he says.
Scharf says the pilot took more than 1,500 photos. While he glanced at every photo, he carefully estimated the yield lost for each photo, which showed six to eight corn fields.
He then used acreage reports from the National Agricultural Statistics Service times the amount of lost estimated in each photo.
In areas he didn’t travel, Scharf used areas that reported the same amount of precipitation to estimate yield losses.
In Southern Illinois and Southern Indiana, he reduced the yield loss because of reports of the amount of sidedressing that is normally done in those areas.
Scharf then used $5 per bushel for the price of corn to estimate how much revenue farmers lost due to the amount of N that was washed away.
He notes there were some good-looking fields in the photos. Scharf is interested to find out which management practices were done in those fields.
While some farmers are reporting decent yields given the weather conditions, he says many of the yields could have been better.
The Iowa Soybean Association On-Farm Network has also reported lost N in its statewide stalk nitrate survey. In 791 fields in 94 counties, 57 percent of the samples fell into the low or marginal categories. Only 19 percent of the samples tested high.
The test measures the amount N available to and taken up by the plant and not a measure of the amount of fertilizer that was applied.
While $2.3 billion gets people’s attention, Scharf says there are N deficiency problems every year.
“This year was the biggest,” he says.
In total, he estimates 14.6 million acres needed some additional N applied in 2008. Scharf compares that with the 12 million acres of crops that got sprayed for fungicide in 2007.
He says that means there could be enough equipment to apply additional N. After talking to industry experts, Scharf says the availability of rail cars and transporting fertilizer would be the biggest holdup.
Farmers should use this as a lesson to prepare how they will handle excess rainfall in the future and if and how they will try to recover some of their yields, Scharf advises.
He says farmers can use aerial photos after the corn is waist high to help determine which fields need additional fertilizer.
Work is being done to develop a computer program that might diagnose some problems at an earlier stage. However, he says the computer modeling would be more regionally based and less accurate.
Source: http://iowafarmertoday.com/articles/2008/12/30/top_stories/nitro.txt
