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(Posted by Tom Horton.)
In recent weeks there’s been a two-pronged push by agricultural interests to credit farmers with already doing most of what’s needed to reduce pollution; also to discredit federal computer modeling that says farmers need to do a lot more to meet the Chesapeake Bay restoration goals.
The extra credit comes courtesy of the U.S. Department of Agriculture’s Natural Resources Conservation Service; the challenge to EPA’s modeling effort comes in a lawsuit filed by the American Farm Bureau.
There’s no doubt farmers in the Chesapeake Bay watershed have installed a lot of good conservation practices, and that not all of these have been accounted for.
There’s also little doubt that the Bay computer model used by EPA could be better, particularly where agriculture is concerned.
But that doesn’t come close to justifying claims that farmers are nearly home free—in fact it could mean they have farther to go than we thought.
Here’s why: In all the back and forth of recent weeks, there’s been a dearth of real numbers, of actual monitoring of exactly how much pollution is moving off farm fields around the watershed.
The Bay model, the NRCS report and other reports by environmentalists that contradict it all must rely more than one would like on surveys and estimates.
There are precious few real-world monitoring efforts like Green Run on Maryland’s Pocomoke River, that have gathered highly credible data on farming practices and water quality for years.
What they show is both heartening and sobering: that if farmers stop applying manure to their lands and plant winter cover crops, water quality improves significantly—though perhaps still not enough to meet Bay restoration goals.
The downside is such practices are well beyond what most farms are doing in the region, and in other regions with large surpluses of animal manure.
In the control part of the Green Run experiment, for example, a subwatershed in Delaware where farming proceeded normally (and legally, meeting all Delaware’s water quality standards), pollution remained high. Yet if you ask Delaware officials, farmers there are all mostly in compliance with Bay restoration programs.
Another key data source—the levels of potentially polluting nutrients in farm fields—remains largely unavailable to EPA modelers, water quality managers and agricultural officials. It’s private and farmers aren’t required to make it known.
And some farming practices that are good for the environment and farmers in important ways, may not be good in other ways.
A case in point is “no till,” or “conservation farming,” where no plow breaks the soil; rather special equipment cuts a narrow slit, inserting seeds and covering the mini-furrow back up. This saves energy and holds soil on fields instead of letting it runoff; also holds phosphorus, which binds to soil and can harm the Bay if it moves off the land.
But conservation tillage also means farmers can’t work manure into the soil, which means it can run easily into waterways; it also does little or nothing to hold nitrogen, another Bay pollutant on the land, because nitrogen dissolves and moves to waterways through groundwater.
Currently the EPA model may actually over-credit farmers for this widespread conservation practice—at least in terms of how much they are helping water quality.
Again, there’s too little actual monitoring to sort this out.
There is, of course, monitoring of a sort. It’s called Chesapeake Bay; and in regions where agriculture dominates the land uses, water quality simply hasn’t been improving, or has improved only slightly. In some cases it’s gotten worse.
Model bashing’s easy, and we can trot out dueling surveys and estimates for years to come; meanwhile there’s real evidence that the Bay’s not improving.
That’s surely not all because of agriculture. Nitrogen comes from almost everything humans do, and sewage plants are big sources of phosphorus.
In fact there’s no need to single out farmers, rather to include them when we say, with absolute certainty: no source of Bay pollution is close to doing all it needs to do.