Thursday, December 15, 2011

USDA urges farmers to limit use of fertilizer to protect waters

America's farmland is generally over-fertilized and pollutes waterways with an abundance of nitrogen and phosphorus, NPR's Dan Charles writes on his blog, The Salt. To reduce the amount of agricultural nutrients in waterways, the U.S. Department of Agriculture has drafted the National Nutrient Management Standard, which outlines ways farmers can reduce spreading nutrients outside their fields.

Charles says the rules involve "putting farmland on a sensible diet," in which the land is "fed" only what it needs. Farmers are also instructed to not apply fertilizer, even manure, when crops don't need it, and to try and capture excess nutrients though planting "cover crops" that will trap nitrogen before it reaches waterways.

The nutrient guidelines are not enforceable regulations, though states can make them mandatory, Charles reports. However, the head of  USDA's Natural Resources Conservation Service, Dave White, has said farmers will adopt the practices out of "economic self-interest" because fertilizer is expensive and wasting it costs money. Self-interest can work against a nutrient-reduction solution, though, Charles says, because an experiment at Michigan State University's Kellogg Biological Research Station showed nitrogen-reduction plans require farmers to "scale back their expectations modestly, rather than pursuing the highest yields of the most profitable crop, which is corn." (Read more)

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