Make the Most of Manure

Proper Management Makes Manure Problems Moot

Russ Quinn
By  Russ Quinn , DTN Staff Reporter
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Attendees of the University of Nebraska-Lincoln (UNL) Extension's Optimizing Poultry Manure Value in Cropping Systems meeting broke into smaller groups at the Feb. 26 gathering in David City, Nebraska. The two groups had to identify preferred fields for applying manure. (DTN Photo by Russ Quinn)

DAVID CITY, Neb. (DTN) -- Applying manure to fields for fertilizer is often perceived negatively, despite recycling nutrients from animal waste.

Issues with over-application fouling ground water sources and the unpleasant smell has left some rural residents at odds with neighbors.

These concerns have heightened recently in eastern Nebraska with Costco building a chicken processing plant in Fremont and farmers across the region constructing large-scale chicken-feeding operations.

A recent University of Nebraska-Lincoln meeting titled "Optimizing Poultry Manure Value in Cropping Systems" was held in David City to show how manure can safely replace commercial fertilizer while offering soil health benefits.

ORIGINAL GREEN FERTILIZER

Farmers have used manure to fertilize crops since the beginning of agriculture, according to UNL Extension Engineer Amy Schmidt. What has changed is specialization has pushed the number of livestock in feeding operations upwards, which increases manure volume.

All manure is not the same, she said. What goes into livestock feed and how animals digest it determines what comes out and what nutrients are found in the manure.

Schmidt said the percent of total solids of manure varies depending on the animal species. How manure is stored or treated also affects its final handling and nutrient characteristics. Stockpiled manure, for instance, might have lower levels of nitrogen (N), she said.

The nutrient value of poultry manure, often called chicken litter, depends on the kind of operation, she said.

"Broiler litter is a fairly drier manure compared to other livestock such as cattle or hogs or even egg layers," Schmidt said.

Broiler litter's average nutrient composition is 64 lbs./ton of nitrogen (N), 54 lbs./ton of phosphorous (P) and 48 lbs./ton of potassium (K).

Breeder poultry manure's average nutrient make-up is 31 lbs./ton N, 40 lbs./ton of P and 35 lbs./ton of K.

Layer manure has higher levels of nutrients, consisting of 40 lbs./ton N, 94 lbs./ton of P and 58 lbs./ton of K.

WHAT IS CHICKEN LITTER?

UNL Extension Animal Manure Management Coordinator Leslie Johnson said most of the broiler feeding operations in the state use an open floor plan with dirt floors and wood shavings. Birds are moved into the building for a six-week period, then the building is empty for two weeks before another group is set to move in.

Generally, six groups of birds are housed in the building during the course of the year, she said.

During the two-week period the waste product is windrowed into a pile and partially composted. The composting process dries out the manure and also eliminates issues with pathogens in the litter. Before more birds enter the building, the compost is spread out again, she said.

Johnson said this process is repeated through the year. An annual cleanout once a year is done to the building, the litter is then spread on fields for fertilizer and more wood shavings are then added.

Odor is an issue of concern for many people living near chicken feeding facilities. "It has an earthy smell but it's isn't as bad what I think many people believe chicken litter will smell like," Johnson said, as she passed around a sample of composted chicken litter to give meeting attendees a sniff.

UNBALANCED FERTILIZER

Another challenge in using chicken litter is it is an unbalanced fertilizer, said UNL Extension Specialist in Biological Systems Engineering Rick Koelsch. Manure sources commonly oversupply P compared to N.

Typically an application of manure can supply soil with several years of P requirements for a corn-soybean rotation. Koelsch recommended farmers do not re-apply manure to the same field until soil testing suggests P and K levels are again low.

"Manure should be applied at a rate that doesn't exceeded the crop's N requirements for a single year and manure applied at rates near the crop's N requirement typically over-apply P and K," Koelsch said. "However, these nutrients will continue to be available to crops in future years."

Koelsch said the key to recycling nutrients back into the soil from poultry manure is finding access to enough acres to apply it while not over-applying.

For example, a 42,000-head broiler operation will need a minimum 40 acres to apply the correct amount of N and 600 acres for the right amount of P annually to grow a 200-per-acre corn crop, he said.

Those with more manure than acres could market the manure to nearby row-crop farmers. Broiler litter is estimated to cost $62/ton based on a 2019 estimate of commercial fertilizer prices, he said.

ADDITIONAL BENEFITS

Manure applications can boost soil organic matter and create well-aggregated soils which will reduce erosion and increase water-holding capacities, Koelsch said.

Another benefit is less soil crusting, which can restrict seedling emergence and movement of air and water into soils. Seed-to-soil contact can be improved with soils that see a manure application, he said.

For more information about manure management, visit UNL's Manure Management website at https://water.unl.edu/….

Russ Quinn can be reached at russ.quinn@dtn.com

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Russ Quinn