“Nutrient crediting from manure is like on-line shopping,” according to Amber Radatz, co-director of the UW-Extension’s Discovery Farms program.
Speaking at the Discovery Farm’s annual conference in Wisconsin Dells last week, Radatz illustrated, “When you order it online you wait for it to arrive. If it doesn’t arrive you don’t put out another order. You check to see where it is.”
According to Radatz manure is the most complex issue to deal with on a dairy farm. When there are close neighbors, there needs to be a concern for odors. When there is not enough storage, decisions need to be made about when and where to spread it, particularly in winter when a growing crop will not immediately take up the nutrients.
To manage it producers need to know the value of the manure, when that value is delivered, how much is enough for a crop and how much is too much.
“We are here to provide science and tools to deal with manure, balancing and protecting the environment while being agronomically successful,” she says.
Discovery Farms provides access to the tools and farmers must figure out which one is best for their farm and how they will put it to use.
UW-Discovery Farms has monitored water quality on farms that utilize manure for over a decade.
Radatz says, “There is tremendous power in understanding the conditions that lead to runoff and a heightened risk for nutrient loss. Using that knowledge to make small tweaks can pay big dividends towards achieving sustainable levels of nutrient loss.”
Things like depth of snow, how it melts, how frozen the soil is, and rain all determine the amount of runoff during winter, especially in the month of March, she points out.
To avoid problems she suggests avoiding manure application shortly before snowmelt and runoff. Also, consider placement. Using no till or limited tillage does a great job of minimizing soil loss.
Continuous surface application of manure without incorporation creates high levels of phosphorus in the upper soil layer that can lead to increased dissolved phosphorus.
Radatz admits it can be a challenge to get good placement of nutrients without doing too much disturbance and causing soil loss.
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