|Janzen, H - AGRI & AGRI-FOOD CANADA|
Submitted to: Environmental Pollution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 24, 2001
Publication Date: January 1, 2002
Interpretive Summary: Rangelands occupy about 161,000 hectares in the U.S., about 48% of our grazing lands. Research has shown that improved management can increase carbon storage in the soils of those rangelands that have been degraded or would respond to better management. Grazing, fire, and fertilization have been shown to affect soil carbon storage in rangelands. Maintaining Conservation Reserve Program lands in grass and improving management could result in as much as 43 MMgC/yr either being sequestered in rangeland soils or not lost due to grasslands being converted back to cropland. Increasing soil organic carbon in soils improves soil quality, productivity and long- term sustainability.
Technical Abstract: The U.S. has about 336 Mha of grazing lands of which rangelands account for 48%. Changes in rangeland soil C can occur in response to a wide range of management and environmental factors. Grazing, fire, and fertilization have shown to affect soil C storage in rangelands, as has converting marginal cropslands into grasslands. While losses due to soil erosion can influence soil C storage on rangelands, most important is the effect of erosion on soil C redistribution on the landscape through detachment and subsequent deposition. Proper grazing management has been estimated to increase soil C storage on rangelands from 0.1 to 0.3 Mg C ha- yr-1 and new grasslands have been shown to store as much as 0.6 Mg C ha-1 yr-1. Grazing lands are estimated to contain 10-30% of the world's soil organic carbon. Given the size of the C pool in grazing lands we need to better understand the current and potential effects of management on soil C storage.