Environmental and conservation groups want farmers to do more to protect the nation's soil, but three powerful forces - overheated food demand, policy choices and climate change - could trip up those efforts.
Rising world demand for farm products is boosting commodity prices. The market is telling farmers to produce more. Farmers can produce more through higher yields, more acres or both. High prices for extra bushels encourage farmers to encroach on grass waterways and other conservation practices to get a few extra bushels. High prices tempt landowners to take land out of Conservation Reserve Program when leases are up. Those soils will be more vulnerable if they are put back into productive use.
Second, budget cutting fever in Washington suggests federal taxpayer spending for conservation practices is unlikely to rise anytime soon. Cash-strapped state coffers face similar constraints.
Third, climate change could derail everyone, shifting rainfall and other weather patterns on a global scale.
Sure, you may not believe in climate change. But policy changes are being put in place, regardless. Iowa State University agricultural meteorologist Raymond Arritt suggests heavy rainfall events are occurring more often. Plus, when they come, they dump more water. He links the rise in rainfall intensity and frequency to climate change.
In many watersheds you'll find folks who believe that in the last 20 years they've had two or three floods that are only supposed to occur once in 100 years.
Erosion on the rise
In April 2010, USDA's Natural Resources Conservation Service released data estimating the rate of soil erosion on U.S. agricultural land. On the surface, the data in the 2007 national resources inventory is reassuring. Erosion in Iowa averaged 5.2 tons per acre per year for example, only slightly higher than the allegedly "sustainable" rate of five tons per acre per year for most Iowa soils. That's the amount soil can supposedly lose each year without reducing productivity.
Across the entire Corn Belt, erosion averaged only 3.9 tons per acre per year. "However, evidence indicates soil erosion and runoff from cropland is far worse than these estimates," declares the Environmental Working Group's Craig Cox. "In some places in Iowa, recent storms have triggered soil losses that were 12 times greater than the federal government's average for the state, stripping up to 64 tons of soil per acre from the land."
Farmers will adjust
"Agriculture has and can adapt to changing climate," says Jerry Hatfield, Director, National Laboratory for Agriculture and the Environment, Ames, Iowa. "For centuries farmers have selected the best crops for their regions, changed their cultural practices to cope with risks from environmental stresses and modified their practices to reduce the impacts of biological stresses caused by weeds, insects and diseases, which also respond to climate.
"Research has been able to help speed this process by providing information to help guide decisions about the impacts of climate on agricultural systems and the magnitude of the response from various stresses."
In addition to the general trends in climate, extremes in temperature and precipitation that occur within the growing season are major factors. That could make conservation practices advantageous - and definitely more necessary than ever. It's a proven fact that no-till practices conserve moisture, grow organic matter and stand up better to weather extremes like heavy rain or drought.
"Extremes in precipitation events early in the growing season when the soil is largely unprotected by the crop or when the crop residue has been removed create situations in which erosion events can be large," warns Hatfield. "These intense precipitation events will cause even more erosion. Eroded soils will be susceptible to climate extremes and climate change, and reduce the potential for high yields or efficient production."