first paragraph, "Maintaining and increasing soil organic matter (SOM) adds to soil fertility, water retention, and crop production. Recently, many soil scientists have suggested that the sequestration of atmospheric carbon dioxide in SOM could also contribute significantly to attempts to adhere to the Kyoto Protocol. Conversion of large areas of cropland to conservation tillage, including no-till practices, during the next 30 years could sequester all the CO2 emitted from agricultural activities and up to 1% of today's fossil fuel emissions in the United States (1). Similarly, alternative management of agricultural soils in Europe could potentially provide a sink for about 0.8% of the world's current CO2 release from fossil fuel combustion (2). Beyond conservation tillage, however, many of the techniques recommended to increase carbon sequestration in soils contain hidden carbon "costs" in terms of greater emissions of CO2 into the atmosphere."
