Changing Ag Practices Could Reduce Global Warming

Changing Ag Practices Could Reduce Global Warming

ENS) – Better management of agricultural lands in the U.S. could help reclaim the 100 to 300 million tons of carbon that escapes into the atmosphere each year, says a researcher at Ohio State University. Carbon is considered one of the key pollutants contributing to global warming.

Agricultural lands, which include crop, pasture and grazing lands, comprise about 42 percent of the total landmass of the U.S. In the last 200 years, almost five billion metric tons of carbon has been released into the atmosphere because of land use changes, such as plowing, drainage and residue removal in the U.S., said Rattan Lal, a professor of natural resources at Ohio State. Each year, accelerated soil erosion releases about 15 million metric tons of carbon into the atmosphere in the U.S. alone.

"Soil can either be a source of, or a sink for carbon -- it can either emit carbon or take it in," said Lal. "We need to start practicing ways to take it in. And we can do that by changing how we manage the land."

Lal presented his findings with John Kimble and Ronald Follett, both with the Department of Agriculture, on Monday at the American Geophysical Union meeting in San Francisco.

"Agricultural land has the potential to sequester carbon while improving the quality of soil and the environment," Lal said.

His suggestions for improving carbon sequestration in agricultural lands include:
  • Converting traditional plowing practices to conservation tillage

  • Growing cover crops during the winter, such as alfalfa and hay

  • Protecting marginal land, such as steep slopes, under the Conservation Reserve Program

  • Planting vegetation with deeper roots in order to control erosion

  • Limiting the areas where cattle are allowed to graze

  • Restoring degraded lands through planting and grazing management

  • Leaving vegetation on steep slopes to reduce erosion
"Sequestering carbon in soil is only a short term solution," Lal warned. "Soil has a finite capacity to hold carbon. If these practices were adopted today, the 'sink' would be full in 25 to 50 years."

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