These can permanently bind carbon that would otherwise combine with oxygen in the air to form CO2, absorbing perhaps a third of the total reductions the Kyoto agreement seeks from the United States. Excess carbon dioxide is trapping enough of the planet's heat to unnaturally change Earth's climate, many scientists fear. Lal estimates that with proper management, U.S. farmers and ranchers could store an additional 105 million to 208 million tons of carbon each year in the nation's 370 million acres of cropland. Lal says the nation's agricultural soils, since the original forests were cleared and the virgin prairies broken by the plow, have probably lost 50 tons or more per acre of their carbon stores. Another scenario for farmers would have them receive credits for carbon stored.
Many people think it's time for payments to shift toward rewarding good stewardship.
It would benefit states like Maryland, where farmers are pushed by water-quality goals to set new environmental standards. Storing more carbon permanently involves some uncertainties for farmers. Plowing, for example, is a major no-no. Within minutes after spring plowing, carbon begins combining with air to form CO2, a process that continues for weeks, Lal says. Many farmers plant without plowing for a few years at a time, but most plow some years to help manage weeds and pests.