Turfgrass can reduce carbon footprint

N.C. State University is looking toward turfgrass to improve carbon sequestration.

November 18, 2010
Allison Saito
Industry News

Fertilizer, pesticides, water use, and mowing lawns and sports fields require can lead to criticism by environmentalists. But these activities may be offset by the carbon absorbed by turf.

As part of their life processes, turfgrasses can store carbon above and below ground and deposit carbon into the surrounding soil. Current research in the department of crop sciences is investigating this process and its effects.

Danesha Seth Carley, a senior research scientist who collaborates with this project, explained how turfgrass compares to trees in terms of the rate of carbon sequestration.

"Turfgrass sequesters a quarter of the carbon that trees do… in terms of tons of carbon being sequestered per acre per year," Carley said.

According to Carley, turfgrass removes about one ton of carbon from the atmosphere per hectare every year. By these numbers, a college football field sequesters approximately half a ton of carbon each year.

Over the past three years, Tom Rufty, professor of crop science, has collaborated with his colleagues to research the amount of carbon that different turfgrasses sequester in the North Carolina environment and the carbon footprints of managed landscapes.

"The way that most of the turfgrass systems are coming out, they can either be positive or negative. They are right on the edge of neutrality," Rufty said. "It depends on how they are being managed and what the total inputs are."
Rufty said proper management is key.

"If people are doing it wisely and following good management practices, usually, they will come out to be slightly positive [amount of carbon stored]," Rufty said.

He explained that the key is having reasonable input levels and using "precise management [and] intelligent approaches to management."

Rufty offered the example of fertilizing lawns.

"All of us have the tendency to go down to Lowe's and buy a twenty-five pound bag of fertilizer because it is cost effective. We take it home, and we don't want it sitting in the garage… so, we start putting it down. In reality, you may only need two pounds of [fertilizer] to fertilize your lawn."

Carley, who collaborates with Rufty, explained some of the variables that affect the rate of carbon sequestration.

"A lot of [the amount of] carbon sequestered has a lot to do with the soil and environment that the grass is grown in," Carley said.

Other factors include how the plant is cared for.

"The plant is storing more carbon in the early years. As it gets older, it stores less carbon," Carley said.

The wide number of factors that affect how turfgrass stores carbon leaves plenty of room for further scientific exploration.

"Like everything is science, you never know enough. We are continuing on with the programs," Rufty said. "Our big push right now is to find out how much management you can put into turfgrass systems and still keep them carbon neutral or positive."

Other members of the crop science department are also working to make this research easily accessible to residents throughout North Carolina.

"We are doing work with carbon calculators… trying to assemble enough information where we can get an overall carbon footprint number that is more precise," Rufty said.

"We have a carbon calculator that we have been working on, a computer program that was written by [Shannon Sermons]," Rufty said.

This calculator would enable people to estimate the carbon footprint of carbon absorbed by their home lawns.

"They can do some measurements and be able to calculate what the positives are their getting from the plant material at their home," Rufty said. "Then, we have an extra component where they can determine how much of their carbon cost by driving they can offset."

The calculator should be available online within a few weeks.