Using tree tannins to target manure odor

June 17, 2014 by Ann Perry
In a swine facility near Peoria, Illinois, microbiologist Terry Whitehead collects fresh manure samples to use in tests to identify bacteria that may be involved in odor production. Credit: Keith Weller

Tannins from the quebracho tree can control the production of compounds that cause manure odors, according to studies by U.S. Department of Agriculture (USDA) scientists. This research may someday give livestock farmers options for odor control that help protect animal health and restore harmony between rural producers and nearby residents.

The study was done by Agricultural Research Service (ARS) scientists in Peoria, Ill. ARS is USDA's chief intramural scientific research agency.

Hydrogen sulfide and other sulfur compounds make up about half of the offensive odorants from swine manure. Scientists have determined that a group of microbes called sulfate-reducing bacteria generate these compounds as part of the process of breaking down manure. Bacterial activity in manure pits also generates methane and nitrous oxide, which are both greenhouse gases.

Research conducted by scientists elsewhere indicated that tannins-compounds naturally present in tree leaves and other feed materials-can block bacterial activity in the guts of ruminant livestock. Drawing on this research, ARS microbiologists Terry Whitehead and Mike Cotta, who work at the agency's Bioenergy Research Unit in Peoria, conducted a laboratory study to see if quebracho tree tannins could suppress odor-generating bacterial activity in manure.

The scientists incubated swine manure under laboratory conditions that mimic on-farm conditions, which allowed them to monitor gas emissions and sulfate-reducing bacteria populations. Seven days after the researchers added quebracho tannins to the manure, they found and methane production had been reduced more than 90 percent and that production continued to dwindle for another three weeks. Populations of sulfate-reducing bacteria also significantly declined, by 70 percent to 90 percent, in the tannin-enriched mix.

Field studies are now needed to determine if using quebracho tannins in manure pits can significantly reduce the activity of sulfate-reducing bacteria and hydrogen sulfide and methane levels under commercial conditions. If successful, this approach would provide producers with a cost-effective method of mitigating odors and greenhouse gas emissions, and the added tannins would not pose a risk to the environment when the is eventually spread onto the fields as fertilizer.

Whitehead and Cotta published their results in the December 2012 issue of Applied Microbiology and Biotechnology.

Explore further: New strategy aims to reduce agricultural ammonia

More information: Read more about this work in the May/June 2014 issue of Agricultural Research magazine.

Related Stories

New strategy aims to reduce agricultural ammonia

May 11, 2011

As concerns about air pollution from large dairies and other concentrated animal feeding operations (CAFOs) continue to mount, scientists are reporting a practice that could cut emissions of an exceptionally abundant agricultural ...

With feedlot manure, it pays to be precise

June 2, 2011

The same precision farming techniques that work with crops can work with manure management on cattle feedlots, according to U.S. Department of Agriculture (USDA) scientists.

USDA patents method to reduce ammonia emissions

November 1, 2012

Capturing and recycling ammonia from livestock waste is possible using a process developed by U.S. Department of Agriculture (USDA) researchers. This invention could help streamline on-farm nitrogen management by allowing ...

The lifetime journeys of manure-based microbes

February 22, 2013

Studies at the U.S. Department of Agriculture (USDA) are shedding some light on the microbes that dwell in cattle manure—what they are, where they thrive, where they struggle, and where they can end up.

New probiotic improves pig health, reduces manure output

March 28, 2014

A new probiotic for pigs could mean less manure to manage, according to U.S. Department of Agriculture (USDA) studies. Agricultural Research Service (ARS) scientists conducted the first published investigation of the use ...

Recommended for you

History shows more big wildfires likely as climate warms

October 5, 2015

The history of wildfires over the past 2,000 years in a northern Colorado mountain range indicates that large fires will continue to increase as a result of a warming climate, according to new study led by a University of ...

Predictable ecosystems may be more fragile

October 7, 2015

When it comes to using our natural resources, human beings want to know what we're going to get. We expect clean water every time we turn on the tap; beaches free of algae and bacteria; and robust harvests of crops, fish ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.