WEST LAFAYETTE, Ind. — Applying manure to a tiled field doesn’t have a negative effect on nearby water – in terms of carbon – when compared to other fertilizer systems, according to a Purdue University study.

Using six years of drainage data, Ron Turco and Sylvie Brouder, both professors of agronomy, found that the use of swine manure lagoon effluent in a tiled agricultural field did not increase the amount of carbon leaching into nearby waterways. The results of their study were detailed in a recent issue of the Journal of Environmental Quality.

“It was surprising in a way that carbon loads were relatively low at the discharge points,” Brouder said. “The assumption was that manure was adding significantly.”

Tiles set below the surface of agricultural fields direct excess water out of the soil and, eventually, into a nearby stream. There has been a concern that tiles flush manure, manure components such as dissolved carbon, or other soil nutrients into water systems faster, damaging water quality.

Carbon is a concern because bacteria, such as E. coli, consume carbon. Adding carbon to a stream could improve conditions for microbial growth, including harmful bacteria. Manure lagoon effluent, the liquid formed and used as fertilizer after manure is stored in lagoons, contains a high amount of carbon.

“In general, we didn’t see more carbon in manure systems, but rainfall near an application event did promote some movement,” Turco said. “However, we didn’t see a huge fluctuation out of any of these agricultural systems, but we are still looking at the nitrogen data.”

Turco and Brouder, along with former graduate student Matt Ruark, measured the carbon emissions from 1999 to 2004 at the Purdue Water Quality Field Station, a research facility that allows scientists to study the effects of farm management practices on water quality. The study included four blocks of 12 plots each with different crop rotations and varied fertilizer-application practices.

Carbon emission into streams was the same in tiled fields fertilized with manure as in tiled fields using other sources of fertilizer. The amount of carbon reaching waterways increased in all fields during years with higher rainfall totals.

“We saw a few blips, things where there was a heavy rain after a manure application, but nothing that was statistically significant,” Turco said.

The U.S. Department of Agriculture funded Turco and Brouder’s research. They said the next step is to evaluate how antibiotics and hormones from manure are transferred to streams through tiled fields.

WEST LAFAYETTE, Ind. — A Purdue University study shows that introducing a new hybrid of the American chestnut tree would not only bring back the all-but-extinct species, but also put a dent in the amount of carbon in the Earth’s atmosphere.

Douglass Jacobs, an associate professor of forestry and natural resources, found that American chestnuts grow much faster and larger than other hardwood species, allowing them to sequester more carbon than other trees over the same period. And since American chestnut trees are more often used for high-quality hardwood products such as furniture, they hold the carbon longer than wood used for paper or other low-grade materials.

“Maintaining or increasing forest cover has been identified as an important way to slow climate change,” said Jacobs, whose paper was published in the June issue of the journal Forest Ecology and Management. “The American chestnut is an incredibly fast-growing tree. Generally the faster a tree grows, the more carbon it is able to sequester. And when these trees are harvested and processed, the carbon can be stored in the hardwood products for decades, maybe longer.”

At the beginning of the last century, the chestnut blight, caused by a fungus, rapidly spread throughout the American chestnut’s natural range, which extended from southern New England and New York southwest to Alabama. About 50 years ago, the species was nearly gone.

New efforts to hybridize remaining American chestnuts with blight-resistant Chinese chestnuts have resulted in a species that is about 94 percent American chestnut with the protection found in the Chinese species. Jacobs said those new trees could be ready to plant in the next decade, either in existing forests or former agricultural fields that are being returned to forested land.

“We’re really quite close to having a blight-resistant hybrid that can be reintroduced into eastern forests,” Jacobs said. “But because American chestnut has been absent from our forests for so long now, we really don’t know much about the species at all.”

Jacobs studied four sites in southwestern Wisconsin that were unaffected by the blight because they are so far from the tree’s natural range. He compared the American chestnut directly against black walnut and northern red oak at several different ages, and also cross-referenced his results to other studies using quaking aspen, red pine and white pine in the same region.

In each case the American chestnut grew faster, having as much as three times more aboveground biomass than other species at the same point of development. American chestnut also sequestered more carbon than all the others. The only exception was black walnut on one site, but the American chestnut absorbed more carbon on the other study sites.

“Each tree has about the same percentage of its biomass made up of carbon, but the fact that the American chestnut grows faster and larger means it stores more carbon in a shorter amount of time,” Jacobs said.

Jacobs said trees absorb about one-sixth of the carbon emitted globally each year. Increasing the amount that can be absorbed annually could make a considerable difference in slowing climate change, he said.

“This is not the only answer,” Jacobs said. “We need to rely less on fossil fuels and develop alternate forms of energy, but increasing the number of American chestnuts, which store more carbon, can help slow the release of carbon into the atmosphere.”

Carbon dioxide is considered a major greenhouse gas, responsible for rising global temperatures.

Jacobs said that since this study looked at aboveground carbon sequestration, future studies would seek to understand more about how forests that contain American chestnuts store carbon below the ground. The Stry Foundation, Electric Power Research Institute, and Hardwood Tree Improvement and Regeneration Center funded the research.

WEST LAFAYETTE, Ind. — Farmers and landowners could receive extra income from already-existing land management practices by selling carbon credits on the Chicago Climate Exchange, said a Purdue University expert.

“Farmers and landowners have an opportunity to sell carbon offset credits into carbon trading markets if they implement certain conservation practices,” said Lenny Farlee, Purdue Extension forester. “Eligible practices include no-till farming – if implemented between 2006 and 2010 – grassland plantings that have been done since 1999, as well as forest tree plantings done since 1990.”

Carbon offset credits are emissions credits earned by eligible offset projects that sequester, destroy or displace greenhouse gas emissions.

Farlee said that forestland owners involved in the Indiana Department of Natural Resources’ Classified Forest Program also have an opportunity to trade carbon offset credits on the growth of their forest properties.

Before jumping in, Farlee said there are a couple of things farmers and landowners need to consider when determining whether to sell carbon offset credits.

“You are signing a contract to keep a practice in place,” Farlee said. “If the practice is removed, you would have to pay for the carbon that you’ve already been paid for.

“Once you understand that you are entering a contractual agreement and you are sure you are going to keep the practice, putting carbon credits on the market is actually another way to get a little bit of income.”

Last summer carbon had a value of $7 per ton. For an idea of just how much potential income selling carbon offset credits could provide, Farlee said no-till yields three-fifths of a ton of carbon per acre on Indiana farms. So for one 50-acre field a farmer could generate $210 of additional income with carbon valued at $7 per ton.

Grassland plantings yield 1 ton of carbon per acre per year, and tree plantings can range anywhere from 1-3 tons per acre per year. However, the value of carbon has dropped significantly, Farlee said.

Today, carbon offset credits are worth about $2 per ton of carbon.

“The price attractiveness is not quite as high as it was this summer, but we’ve got some interesting developments,” Farlee said. “The new administration has indicated an interest in a cap-and-trade program.”

President Barack Obama’s New Energy for America Plan would implement a nationwide cap-and-trade program to reduce greenhouse gas emissions 80 percent by 2050.

“A program like this would put absolute caps on emissions of carbon and allow for trading to help meet those caps through industry buying carbon offset credits from folks that are fixing carbon,” Farlee said.

Before a landowner can trade carbon credits, they must work with an aggregator, someone who accumulates pools of carbon from several different properties to get enough carbon to meet the trading thresholds required by the Chicago Climate Exchange. The aggregator essentially acts as a stockbroker, Farlee said.

A list of aggregators is available on the Chicago Climate Exchange’s Web site at http://www.chicagoclimateexchange.com/content.jsf?id=64. Purdue Extension also has “Cash for Carbon: A Woodland Owner’s Guide for Accessing Carbon Markets,” a publication that includes a short list of aggregators in the Central Hardwoods Region. The publication is available online at http://www.ces.purdue.edu/extmedia/FNR/FNR-228-W.pdf .

“Selling carbon credits is something that farmers and forestland owners should certainly watch as a real opportunity in the future to make some extra income off their property management practices,” Farlee said.

For questions and more information about carbon credit trading, contact Farlee at (765) 494-2153, lfarlee@purdue.edu

WEST LAFAYETTE, Ind. — Earthworms can change the chemical nature of the carbon in North American forest litter and soils, potentially affecting the amount of carbon stored in forests, according to Purdue University researchers.

The Purdue scientists, along with collaborators from the Smithsonian Institution and Johns Hopkins University, study the habits of earthworms originally brought to North America from Europe. They want to determine the earthworms’ effect on forest chemistry by comparing carbon composition in forests that vary in earthworm activity.

Some earthworms eat fallen leaves and other plant material – the litter of the forest floor – while others eat roots or soil organic matter. This begins a decomposition process in which organic materials pass through the animals’ digestive tracts and back into the soil.

The research team found that forests with greater numbers of invasive earthworms tend to have litter and soil organic matter enriched in the plant material lignin, which is typically harder for bacteria to decompose, said Purdue biogeochemist Timothy Filley. Sites with low numbers of these earthworms accumulate plant carbon in forms more easily degraded by bacteria.

Overall, the amount of carbon in the litter and duff layer, which is the surface mat of decaying organic matter and roots, decreases because of earthworm activity. However, the change in carbon chemistry may make it harder for soil organisms to decompose the carbon remains. After earthworms feed on forest litter, they take the carbon down into the soil and mix it in, potentially leading to a buildup of carbon in the soil.

“If the litter just stays on the surface of the soil, then it’s likely that normal oxidation of organic matter happens and a lot of that carbon will just go into the atmosphere,” said Cliff Johnston, a Purdue environmental chemist and professor of agronomy. “However, if carbon can bind to the soil particles, such as clay, it might be a long-term way of stabilizing carbon.”

Another way earthworm activity may affect the fate of carbon and the environment is in the thickness of layers of leaves and debris left on forest floors. Bare soil is generally very dark, absorbing more sunlight, which may dry it out quickly. A layer of lightly colored leaves is moderately reflective and holds moisture near the soil. Either condition may affect factors such as the warming of forest soil and the timing of snowmelt.

“Ultimately, we will look at such things to determine the potential invasive earthworms have in changing the flux of CO2 out of the forest and how much that could impact climate change,” said Filley, who also is an associate professor of earth and atmospheric sciences.

The earthworms that the team studies were brought to North America by early European colonists, probably in the ships’ ballasts or in plant soil. In northern North American forests the settlers found land devoid of such creatures because the worms never reoccupied soils formed when the glaciers melted.

In addition, earthworms don’t move very fast. It’s estimated they have migrated under their own power only about 100-200 kilometers in the past 10,000 years since the glaciers.

“In some forests, such as ones we are working at in northern Minnesota, we find soils where earthworms are only now being introduced.” Filley said. “The main agents of introduction in such areas are discarded fishing bait in nearby lakes, transport between forest sites in tire treads and the movement of soil.”

The research team reported findings of their ongoing study in a recent issue of the Journal of Geophysical Research. The National Science Foundation has provided funds to continue the work.

For this study, Filley, Johnston and their collaborators monitor earthworm activity at the Smithsonian Environmental Research Center forest area in Maryland. The scientists set up plots in which they manipulate the amount of litter on the ground and watch how fast the worms remove it.

In some areas of the forest, more than 350 worms can be found in one square meter.

“The impact of that many worms is huge for the forest ecosystem as from spring to fall they actively consume litter and mix it into the soil, leaving only a bare surface by year’s end.” Filley said.

In contrast, sites that have no earthworms have many years of accumulated litter and organic matter above the soil. This has implications for plant seed germination, water holding capacity and infiltration of the forest floor, among other things.

“The earthworms fundamentally change how the microbial community is decomposing,” Filley said. “When they eat roots, they also eat other organisms that help to distribute nutrients between plants. Worms may throw off the timing of nutrient delivery.”

Other members of the research team are Melissa McCormick and Dennis Whigham, both of the Smithsonian Environmental Research Center; Susan Crow of the Purdue Department of Earth and Atmospheric Sciences and now at Queen’s University Belfast, UK; Katalin Szlavecz of the Johns Hopkins Department of Earth and Planetary Sciences; and Ronald van den Heuvel, formerly of the Smithsonian center and now at Landscape Ecology, Institute of Environmental Biology, Utrecht University, Netherlands. Both Johnston and Filley are members of the Purdue Climate Change Research Center.