weaning our waterways off nitrogen

December 29, 2011 in Essays & Articles

Morgan Heim/AP -- Algae blooms in the mouth of the Elizabeth River in Norfolk, Va., on July 31, 2010. Rain, high temperatures, and pollution from agricultural runoff made for ideal algae bloom conditions.

Putting Farmland on a Fertilizer Diet by Dan Charles for NPR

The U.S. Department of Agriculture released a document yesterday that got no attention on the nightly news, or almost anywhere, really. Its title, I’m sure you’ll agree, is a snooze: National Nutrient Management Standard.

Yet this document represents the agency’s best attempt to solve one of the country’s — and the world’s — really huge environmental problems: The nitrogen and phosphorus that pollute waterways.

There’s a simple reason why this problem is so big, and so hard to solve. Farmers have to feed their fields, before those fields can feed us. Without fertilizer, harvests would dwindle. But lakes, estuaries, and coastal waters lie downstream from highly fertilized farmland, and now they are choking to death on too much nutrition.

Those nutrients typically come from commercial fertilizer, but they don’t have to. Organic growers need to feed their fields, too. Farmers can also use animal manure (which is really recycled fertilizer from the fields that fed those animals) and legumes — crops like alfalfa or chickpeas, which add nitrogen it to the soil.

The problem is, those nutrients don’t stay where they’re needed. They migrate into groundwater, streams, or the air, and everywhere, they cause problems. They feed the growth of microbes and algae, turning clear water cloudy and depriving fish and other creatures of essential oxygen. (There are other important sources of nutrient pollution as well, including urban sewage and the burning of fossil fuels, but fertilizer is the biggest.)

Read the rest of the article here.

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