Bounty for bay in 'cover crops' Pollution: Winter crops can absorb residues of nitrogen fertilizer from the soil, preventing damage to the bay.

On the Bay

February 28, 1997|By Tom Horton | Tom Horton,SUN STAFF

WANT TO SEE a project with as much potential to restore the bay as any single action Maryland could take?

It looks about as impressive as dirt, which is mostly what you see, riding through winter-fallow Dorchester County farmland.

But a subtle change occurs along a road near Vienna, where Russ Brinsfield and his family have farmed for generations. There, a scruffy, brown vegetative cover rises half a foot high.

The plants are spring oats, sown after last fall's harvest and killed by winter freezes. Come spring, Brinsfield won't even bother to harvest them, will just plow them under.

But the little oats will have accomplished yeoman work, sucking up, as they grew, thousands of pounds of residues left from nitrogen fertilizer applied to crops the previous summer.

Without this "cover crop," the nitrogen would have oozed on down into the ground water and, eventually, into nearby creeks and rivers and the Chesapeake Bay.

TC More than any other pollutant, too much nitrogen is killing the bay, clogging it with algae that rob oxygen from aquatic life and shade underwater grasses, depriving them of light.

It comes from everywhere -- sewage, automobiles, septic tanks, power plants. But a huge chunk, about 100 million pounds a year, comes from cropland in Maryland, Virginia, Pennsylvania and New York.

Sometimes you hear skeptics argue that no rational farmer would apply a greater amount of expensive fertilizer than needed to grow a crop. Who would pay good money to let it run into the water?

But several things can happen to cause a polluting excess: An unpredictable drought can stop plant growth -- and fertilizer uptake -- leaving large amounts of nitrogen to escape into the bay.

And farmers with lots of animal manure may spread it in quantities that put nitrogen in the soil well beyond what crops can take up even in a good year.

Nor are farmers the only ones fertilizing farmland. Cities are desperate to get rid of sewage sludge. Spread judiciously on farms, this can be beneficial, but it is sometimes a shell game, shifting nitrogen from sewage into ground water.

Finally, research is showing that current agricultural systems, even under careful management, are just more prone to "leak" nutrients such as nitrogen into the environment than was assumed.

For example, traditional farm pollution controls to reduce rainfall runoff and soil erosion don't stop water-soluble nitrogen, which soaks in quickly and leaves a field mostly through ground water.

Even soybeans, which fix nitrogen from the air and don't need nitrogen fertilizer, still leave considerable amounts in ground water, just from what is released when their roots decay after they are harvested.

About this problem, Russ Brinsfield can tell you more than most farmers. He also has a doctorate and is an agriculture researcher with the University of Maryland, specializing in less-polluting crop practices.

Years of experimenting with winter cover crops at the Wye Research and Education Center in Queen Anne's County has convinced Brinsfield and ecologist Ken Staver that this may be the only way farmers can reliably meet baywide goals of cutting nitrogen pollution 40 percent by 2000.

Brinsfield says he gives agriculture "tremendous credit" for the strides it has made to reduce pollution, but cover cropping techniques that could make an even greater improvement are languishing.

As much as half a million acres of cropland in Maryland (and millions more in the bay watershed) could benefit from winter cover crops. But no more than a few tens of thousands of acres are covered now, perhaps far less.

The problem is partly that farmers need to be persuaded that winter cover crops can fit into their farming practices, says Tom Simpson, a Maryland agricultural scientist working with bay cleanup programs.

But a bigger part is simply money. Cover crops are not eligible for federal-state payment programs traditionally used to help farmers conserve soil and control pollution.

Experts say it would take a subsidy of about $20 an acre to spread cover cropping widely and rapidly. Brinsfield says that if he could target it to about 250,000 acres for starters, he is "confident we could keep 6 million pounds of nitrogen out of the bay each year."

That might seem like a lot of public money -- $5 million -- and after all, it's the farmers doing the polluting, right?

Wrong, on several counts. First, the nitrogen is polluting a bay enjoyed by all of us.

Second, to the extent that excess nitrogen is an inevitable consequence of our current systems of producing cheap and bountiful food, everyone who eats ought to share responsibility.

You could, for example, generate about $5 million annually with a surcharge of one-sixteenth of 1 percent on the part of Maryland's sales tax applied to restaurant meals and bar tabs.

Third, the cost, less than a buck per pound of nitrogen removed, compares well with nitrogen removal via sewage treatment, air pollution and urban storm water controls, and other farm solutions -- which range from a few dollars to nearly $150 per pound of nitrogen kept out of the bay.

It is urgent that we get agriculture's act together now. The time it takes nitrogen to move from fields, through ground water and into the bay can be on the order of decades.

So if we undershoot now on farm cleanup, we may not realize the error for a long time and would then have to wait more years for a revamped effort to have any effect.

As Simpson points out, it's not as simple as just plugging in a winter crop on every farm. But there's little doubt that if cover crops get a major push, ways to adapt them to millions of acres will be forthcoming. And there is reason to think they will have long-term soil benefits that might reduce the need for cost sharing.

Pub Date: 2/28/97

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