Sprayed Fertilizer Method Raises Concerns Over Drifting Manure

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A small number of Wisconsin farms have started using a new way to spray manure on crops. Some citizen groups want more say-so, over whether the method is good for the environment.

When farmers want to use animal waste as fertilizer, they typically apply the waste with a manure spreader pulled behind a tractor. The spreader works just a few inches or feet off the ground.

Now some farms, mainly big industrial-sized ones, are switching to spreading the largely liquid manure through overhead irrigation sprayer systems: the large, wheeled overhead sprinklers you see on some fields. Lyn Utesch is a family farmer in Kewaunee county, and a member of Sustain Rural Wisconsin Network. Utesch says the problem is, those big irrigation systems can apply manure further than intended.

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“[The manure] is also being aerosolized …and causing it to drift, some studies have shown, for up to several miles, and the manure has 160 known pathogens in it.”

Utesch says he worries about the sprayed manure blowing onto other people’s lands and homes, and onto nearby lakes and streams. Utesch wants a state working group on manure irrigation to get more input from critics of the overhead sprayers. The DNR recently asked UW-Extension and UW-Madison professor Ken Genskow to take over as chair of the working group. Genskow promises to hear from all sides, and wants to begin by holding two meetings that sum up the latest research:

“… that lay out what we know about this technology, and its potential benefits and concerns … and what do we need to know, and how we’re going to answer those remaining questions.”

Genskow says supporters of the manure sprayers say they can be used on crops in the summer and reduce the need for manure tanker trucks on rural roads. The discussion comes as there are now more than 200 Concentrated Animal Feeding Operations in Wisconsin, trying to get rid of their large manure piles or waste lagoons.