Bay Journal

VA watershed plan ignores largest source of nutrients, targets smaller sectors

  • By Lynton S Land on October 01, 2012
 (Dave Harp)

Virginia's Phase II Watershed Implementation Plan, submitted to the EPA, does not seriously address the Bay's largest source of nitrogen and phosphorus pollution, namely inefficient agricultural fertilization.

According to the recent U.S. Geological Survey Scientific Investigation Report 2011-5167: "Nitrogen contributions to Chesapeake Bay from the watershed are attributable primarily to agriculture. The combination of manure and fertilizer applications and fixation by crops provides 54 percent of the estimated nitrogen contributions to the Bay…Nearly half (43 percent) of the phosphorus reaching the Bay is contributed from upstream agricultural fertilizer and manure applications." If mineral dissolution is disregarded because it is a natural process, half of the phosphorus pollution is of agricultural origin, and a great deal of it from the disposal of poultry litter by land application.

Four sources of pollution sectors are addressed in Virginia's Phase II Plan. Here are the number of pages devoted to each sectors: forests, 3 pages; onsite waste disposal, 6 pages; urban/suburban, including wastewater, stormwater and combined sewage overflow, 35 pages; and agriculture, 12 pages.

  • Forests cover about 58 percent of the Bay watershed. Nitrogen and phosphorus have always cycled through the forest/Bay ecosystem. Little nutrient pollution reduction can be achieved from this sector because little of the pollution is of anthropogenic origin. It is uncontested that a riparian buffer adjacent to waterways, at least 100 feet wide and containing mature trees, can significantly reduce water pollution. Unlike shrubs and grasses with shallow roots, the deep roots of trees remove nitrate from the groundwater and promote denitrification, or the conversion of nitrate to harmless N2 gas. A ban on timbering within 100 feet of the water would be a simple and effective strategy, but is not advocated.
  • Onsite waste disposal, mostly by conventional septic systems, causes less than 5 percent of the Bay's nitrogen pollution yet it gets half as much attention as agriculture, which causes an order-of-magnitude more pollution. This is one of many examples where Virginia transfers responsibility from where it belongs — agriculture — to the public. If the goal for a large onsite system, according to the report, is to "demonstrate compliance with the <3mg/liter total nitrogen at the project boundary," then shouldn't agricultural fields be required to reach the same nitrogen concentration in groundwater discharged directly to rivers and the tidewater? There are many more acres of agricultural fields than septic systems. According to USGS Circular 1228, on the Eastern Shore, where 69 percent of the nitrogen pollution and 71 percent of the phosphorus pollution is of agricultural origin, "The median concentration of nitrate from 29 wells in agricultural areas was 5.4 mg/l, and the maximum was 37 mg/l. Water in about one-third of the wells exceeded the primary maximum contamination level of 10 mg/l established by EPA." No justification exists for requiring a tiny source of nitrogen pollution, large onsite systems, to be regulated, at great expense, when a very much larger source of pollution is ignored.
  • Urban/suburban pollution receives the most verbiage, which is unjustified because significant pollution reduction has already been achieved, at great expense, from this sector. In the Potomac River watershed, for example, the nitrogen discharge from wastewater treatment plants, in million pounds per year, was 9.8 in 1985, 7.9 in 2002 and 3.6 in 2009. The allocation for 2025 is 3.3. If discharges could be reduced to the limit of technology, it would be about 2.9 MPY. Stormwater nitrogen pollution is about 20 percent of wastewater point-source discharge. Combined sewage overflow is small, and scheduled for elimination. Clearly, this sector is on track. Bay water quality has not meaningfully improved as point-source pollution, directly discharged to the water, has demonstrably been reduced. Further scheduled reductions, desirable and expensive as they are, will have little effect on improving Bay water quality. Yet given these facts, most of the Phase II plan is devoted to this sector, again transferring the blame from where it really belongs.
  • Agricultural fertilization is the largest source of Bay pollution and should receive the most attention. It is critical that the public understand the inefficiency of conventional chemical fertilization. Numerous scientific publications, including from the National Academy of Sciences, document that nitrogen use efficiency — the percentage of applied nitrogen sequestered in the harvested crop — is rarely better than 65 percent. Roughly one third of the nitrogen applied to fields ends up as pollution. Only small amounts of reactive nitrogen are eliminated by denitrification in oxidized soils.

The Phase II plan encourages more bureaucracy/administration and funding for farmers. As an example, consider cover crops planted over winter to consume some of the excess fertilizer applied during the growing season and "fix" additional nitrogen. The cover crop is then incorporated into the soil in spring to reduce the amount of required fertilizer. A good idea? Yes, but only if farmers pay for it and fertilize the next crop based on a soil analysis. Cover crops do not reduce fertilizer application to the preceding crop, so they do not address the root problem, inefficient fertilization. If society pays for cover crops, all we are doing is providing farmers with yet one more subsidy for very little pollution reduction. Pollution must always be addressed at its source. It is always less expensive to stop polluting rather than try to "sop it up" later.

The short "Nutrient Management" section in Virginia's Phase II Plan should address inefficient fertilization practices, but does not. It contains only seven items, replete with phrases like "work with…..", "advocate…" or "investigate opportunities." All seven items are contingent on funding for "partners," "reimbursement," "staff," "certified employees" or "technical service providers."

The EPA must require an implementation plan that leads to meaningful pollution reduction and adheres to President Obama's Executive Order issued in May 2009 to "Establish a clear path to meeting, as expeditiously as practicable, water quality and environmental restoration goals for the Chesapeake Bay." Virginia's Phase II plan does not meet that mandate because it fails to meaningfully address the largest source of pollution.

Unless agricultural fertilization efficiency improves markedly, water quality in the Chesapeake Bay cannot possibly improve markedly. Here's how can we significantly improve agricultural fertilization efficiency without making farming uneconomical:

  • Ban the land application of all animal waste — poultry litter, municipal sewage sludge and manure — if it must be transported on a public highway for disposal so as to exempt small farms. Less than 10 percent of farmers use this "free fertilizer" and the nitrogen use efficiency is no better than about 50 percent. The few farmers who use animal waste will just have to fertilize like most other farmers, who are obviously profitable. The waste should be used as biofuel. The Chesapeake Bay Program Office has estimated that agricultural animal manure and poultry litter contribute about half of the agricultural nutrient load to the Chesapeake Bay. No doubt exists as to the magnitude of pollution caused by the land application of animal waste. So far, the profits of a few farmers and the suppliers of the waste, especially the poultry industry, trump Bay water quality in the eyes of the EPA and Virginia legislature.
  • Impose a "pollution tax" on conventional fertilizer, but not on controlled — slow– or timed-release — products with a goal of increasing nitrogen use efficiency to at least 80 percent. Agronomists must change their focus from "maximize crop yields and damn the consequences" to "improve fertilization efficiency and reduce pollution while maintaining acceptable crop yields."

Documented decreases in point source pollution from wastewater plants have not significantly improved Bay water quality. Improved water quality will only become widespread when we reduce the major source of pollution: inefficient agricultural fertilization.

All of the "light green" efforts — to borrow a phrase from Howard Ernst's book, "Fight for the Bay" — to address tiny sources of pollution can only chip away at the problem, and "fixing the little leaks" cannot result in meaningful Bay water quality improvement.

Because of the magnitude of agricultural pollution, only major changes in the way crops are fertilized can measurably improve Bay water quality. Chesapeake Bay is only one of 7,000 water bodies in the United States formally "impaired" because of nutrient load and listed, but not acted upon, by the EPA. Inefficient agricultural fertilization needs to be addressed on a countrywide, indeed, worldwide scale.

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About Lynton S Land

Dr. Lynton S. Land is emeritus professor of geological sciences at the University of Texas in Austin, and now lives in Virginia.

Read more articles by Lynton S Land

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