Grain producers across the state of Wisconsin are learning more about optimizing nitrogen applications through on-farm studies sponsored by the Wisconsin Department of Agriculture, Trade and Consumer Protection. The various Nitrogen Optimization Pilot Program trials were initiated by farmers on their land and with their particular management styles and environment.
Two-year grants were awarded to 20 farms across the state. Farmers from northwestern Wisconsin along with University of Wisconsin staff gathered recently in Altoona to share their experiences in the first year of their trials.
Joe Ailts in St. Croix County wanted to learn if the Haney soil test would help optimize side-dressing-nitrogen rates. By testing mid-season he hopes to quantify how much nitrogen is available to the plants – and possibly cut back on application rates.
“If there are x number of pounds available for the rest of the season, can you use that number to offset what your nitrogen plan was?” he said. “The interesting thing is that it comes with a whole lot of metrics. I think we are going to get some great answers out of this.
“This was an incredible learning opportunity for us. We did learn a lot of things about how to do this research right.”
The research plot led to questions about proper soybean credits, which is one of the many variables that can change test results.
Joe Bragger and Jimmy Ellis in Buffalo County did a trial study looking at the effectiveness of poultry litter. Contract farmers in the area said they noticed a difference in the power of their chicken manure to increase grain yields – compared to past years – and the two wondered if it was true. They hope the plot will help them find a figure for optimal urea applications to supplement poultry litter as a fertilizer.
Bragger’s father-in-law first grew chickens on his farm specifically as a source of nitrogen for his field crops. Bragger’s family now has three barns – one of pullets for layers and two for meat birds. That adds another wrinkle to the testing because the litter is different in the two types of barns. A field plot was measured out where corn was planted; the poultry litter and differing application rates of urea were applied. It was a challenging year with the dry weather experienced in that area.
Lack of rain also challenged Tryston Beyrer of Red Cedar Conservation Farmers in northern Dunn County. He said the water in his area drains into Lake Tainter. which historically has phosphorous issues. Below the dam in Menomonie, phosphorous levels were increasing until the early 2000s when the levels started to decline.
“Whatever practices the farmers are doing are going in the right direction as far as phosphorous,” Beyrer said.
But well testing in the watershed revealed that one-third of the wells still have inflated levels.
Beyrer put together three trials to find data on the effects of cover-crop termination, manure applications and tillage practices relating to nitrogen efficiency. What happens from farm to farm and sometimes field to field can make a difference in the data. So some project money was used to buy weather stations that tie into online web pages. They also took soil-nitrate samples from 1 to 2 feet in depth to see where the nitrates were moving.
David Tollberg is a member of the Western Wisconsin Conservation Council. To avoid problems with the dry season experienced in 2023, he decided to use irrigated land for his research project. He was interested in using local data for decision-making rather than depending on numbers from other areas of the state. The question that started the project was, “Can yield targets be maintained on irrigated fields at nitrogen rates less than recommendations, and what is the correct recommendation?” He said he wondered at the ability to measure nitrogen leaching and whether it’s possible to measure plant health to predict yield.
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