Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New Strategy Aims to Reduce Agricultural Ammonia Emissions

13.05.2011
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 gas—ammonia—by up to 30%.

In the May-June 2011 issue of the Journal of Environmental Quality, a team led by Mark Powell, a soil scientist with the USDA Agricultural Research Service’s U.S. Dairy Forage Research Center in Madison, WI, describes how natural plant compounds known as tannins can reduce both the amount of nitrogen cows excrete in urine, and the action of a microbial enzyme in manure that converts the nitrogen into ammonia on the barn floor.

The U.S. EPA already monitors ammonia emissions from large animal operations under the “Superfund” act, and in April a coalition of citizen groups petitioned the agency to begin regulating ammonia under the Clean Air Act, as well. Besides its pungent smell, ammonia that volatilizes from cattle manure is highly reactive in the atmosphere, forming particulates that travel long distances and contribute to environmental problems such as acid rain, nutrient pollution, and smog.

Feeding tannins to cattle could not only help dairy farmers reduce these impacts and meet regulatory standards, Powell says, but tannins could also boost nitrogen use efficiency in cows, thereby decreasing the need for expensive protein supplements. Only 20 to 35% of feed nitrogen ends up in milk on commercial dairy farms, with the remainder excreted about equally in manure and urine as the compound, urea.

Urea is produced when nitrogen-rich proteins break down mainly in the cow rumen, forming ammonia gas that’s eventually converted to urea before being excreted. Tannins are thought to cut urea production by somehow allowing more protein to escape digestion in the rumen and enter the cow intestine, where it’s used more efficiently to produce milk protein.

Tannins are perhaps best known for their role in leather tanning, but Powell began investigating them in ruminant feed more than two decades ago in West Africa. In the communities where he worked, tannin-rich shrubs were grown as windbreaks, and to amend the soil and feed livestock. Tannins in the diets of cattle, sheep and goats are in fact well-studied in the tropics, where the vegetation tends to be naturally higher in the astringent plant chemicals, Powell explains. “But tannin research, in terms of ruminant nutrition, is relatively new in temperate environments.”

In the new study, Powell and dairy scientists from the University of Wisconsin-Madison fed tannin extracts from red quebracho and chestnut trees to dairy cows that also received two concentrations of crude protein: a low level of 15.5% protein, and a higher one of 16.8%. What they found is that dietary tannin cut ammonia emissions from the cows’ manure by an average of 30% at the low protein level, 16% at the high level, or 23% overall. In other words, cows that consumed tannin expelled significantly less urea, thus making less available for conversion to ammonia.

But a drop in urea production wasn’t the only effect. To his surprise, Powell discovered that tannins also appear to inhibit urease, the enzyme that converts urea to ammonia. Urease activity in the feces of tannin-fed cows was significantly lower than in the feces of control animals, resulting in an 11% drop in emitted ammonia—or one-third of tannin’s total impact on emissions at the high protein level. And when the researchers applied tannin directly to manure on the barn floor (rather than feeding it to cows), the effect was even greater: Ammonia emissions declined by nearly 20%.

The tannin sources investigated in the study are already approved for animal feed, and “the levels we used amount to pennies per cow per day,” Powell says, suggesting they could offer a cost-effective means to cut ammonia losses from the barn floor, as well as from manure that’s applied to farm fields as fertilizer. Powell is now working with chemists to determine exactly which compounds in the tannin mixtures produce the effect, with an eye toward manufacturing a synthetic substitute later on.

In the meantime, he has set his sights on another important air pollutant that is prodigiously produced by cows. “We have another experiment looking at higher doses of tannin in dairy cattle,” he says. “We want to see if it can reduce methane emissions.”

The full article is available for no charge for 30 days following the date of this summary. View the abstract at https://www.agronomy.org/publications/jeq/abstracts/40/3/907.

The Journal of Environmental Quality is a peer-reviewed, international journal of environmental quality in natural and agricultural ecosystems published six times a year by the American Society of Agronomy (ASA), Crop Science Society of America (CSSA), and the Soil Science Society of America (SSSA). The Journal of Environmental Quality covers various aspects of anthropogenic impacts on the environment, including terrestrial, atmospheric, and aquatic systems.

The American Society of Agronomy (ASA) www.agronomy.org, is a scientific society helping its 8,000+ members advance the disciplines and practices of agronomy by supporting professional growth and science policy initiatives, and by providing quality, research-based publications and a variety of member services.

Sara Uttech | Newswise Science News
Further information:
http://www.agronomy.org

More articles from Agricultural and Forestry Science:

nachricht Plasma-zapping process could yield trans fat-free soybean oil product
02.12.2016 | Purdue University

nachricht New findings about the deformed wing virus, a major factor in honey bee colony mortality
11.11.2016 | Veterinärmedizinische Universität Wien

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>