What limits yield on your farm? Too much water? Not enough? Low soil nutrient levels? Not enough heat? At least one scientist will tell you it's none of the above — the most limiting factor for crop production in North America is actually soil carbon.
"Our soils are starved for carbon," says Kristine Nichols, a research microbiologist, most recently with the USDA-Agriculture Research Service, but soon to be with the Rodale Institute in Pennsylvania. Nichols presented at the recent World Congress on Conservation Agriculture, held in Winnipeg, Man., in late June.