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The discovery of a harmful microbe in three tributaries of the lower Chesapeake Bay in 1997 did not bode well for Maryland's poultry industry. The microorganism found that August and early September--first identified as Pfiesteria piscicida, but later determined by state officials as only being "Pfiesteria-like"--was suspected in the deaths of thousands of fish in the Pocomoke River. It was also viewed as the cause of a mysterious rash that appeared on the skin of local watermen and swimmers. An ensuing "Pfiesteria hysteria" brought forth a phalanx of public interest groups, local and national media, and state and federal officials--all of whom demanded answers.

One popular theory, still debated even today, was that poultry manure applied as fertilizer was sending excess levels of phosphorous into the Chesapeake Bay watershed through runoff and soil erosion, thus creating favorable conditions for ecological chaos. By the time the media frenzy had run its course a year later, Maryland seafood sales had slumped dramatically, environmental groups had launched major media and lobbying campaigns concerning agricultural runoff of chemical fertilizers and animal manure, and Maryland farmers would soon face new mandatory regulations

Discovering a Problem

The Delmarva Peninsula that encompasses the Eastern Shore of Maryland, Delaware and part of Virginia has long had an abundance of poultry litter, the term used for poultry feces mixed with wood shavings from a broiler house. According to Delmarva Poultry Industry Inc., in the year 2000, farmers raised more than 616 million broilers in 5,729 chicken houses that dot the region. These same broilers produced more than a half-million tons of poultry litter in the three states, and 287,000 tons in Maryland alone.

"In the late 1970s and early 1980s, we really started pushing the fact that poultry litter wasn't just a waste product to be disposed of," but something that had to be carefully managed, says Lewis Carr, instructor of biological resources engineering and an extension specialist at the University of Maryland. Carr, working out of a university research center in Princess Anne, Md., has spent the majority of his 29-year career at the university working directly with the region's poultry industry.

Prior to the 1980s, Carr says, poultry litter was mainly seen as a waste product that farmers just wanted to get rid of by any means possible. For decades, they had applied the wastes to farmland as fertilizer, but many weren't paying much attention to the application rates--most farmers would just spread the poultry litter on the same field, in the same spot, year after year.

With the purpose of helping farmers gain maximum benefits from their poultry waste applications, in the mid-1980s the university's College of Agriculture and Natural Resources developed a nutrient management program that was jointly administered with the Maryland Department of Agriculture. "What we originally did was to try and get farmers to focus on poultry litter as a nutrient and get them to understand that its efficient use [on farm fields] was a valuable component in a total farming production system," says Ted Haas, a senior extension agent who recently retired from the university after 30 years of providing information to farmers on Maryland's Eastern Shore.

The university did extensive testing of poultry litter to determine what the average dry ton of manure contained in terms of nitrogen, phosphorous and potash. "And then we were able to go to the farmer and say that if you put this much of the poultry litter on your field at this rate of application, you can reduce or eliminate your [chemical] fertilizer bill," Haas recalls.

The nutrient management program worked well through the late 1980s and early 1990s, with the concept of nutrient management still an educational, voluntary idea that was widely accepted by the farming community. But things weren't perfect. The nutrient plan that University of Maryland extension agents, soil scientists and agricultural economists were recommending to farmers was focused primarily on one component of poultry litter: nitrogen.

"We originally thought that if you could match the nitrogen supply of the manure with the nitrogen demands of the crop you are applying it to--particularly corn and soybean used for poultry feed--then you basically had a nice balanced [production] system," recalls Frank Coale, associate professor in the Department of Natural Resource Sciences and Landscape Architecture. "But we came to realize in looking at our own work, as well as research from other universities, that if we developed a plan based specifically on nitrogen, that we may have a perfect nutrient plan for the nitrogen needs of a plant, but we may also be greatly over-applying the amount of phosphorus which the plant can use."

Coale says that scientists already knew that elevated levels of phosphorus in streams and lakes helped fuel the eutrophication cycle, wherein nutrient overloading in a waterway prompts explosive growth of algae and a resulting plummet in dissolved oxygen, harming other species that live there. "We also knew that certain soils had a fairly large capacity to hold onto phosphorus by a chemical bonding that takes place," he says. But up until the early 1990s, many soil specialists, including Coale, felt that it was difficult to saturate soils with phosphorus to the point it would run off the landscape in great amounts, or worse, begin to leach into the underground water table.

According to Coale, there are two main ways that phosphorus can be transferred off the land and into tributaries like those that feed the Chesapeake Bay. One is called particulate transfer, where phosphorus attaches itself to solid material like sediment or other organic matter that is carried off the land by erosion. "For many years, we thought that if you controlled erosion, then you controlled phosphorus runoff," he says. While that principle holds true in many cases, Coale later discovered that even with strict erosion controls in place, phosphorus was still running off the land, only in a more dissolved form that rendered it virtually invisible. "That opened a lot of eyes," he says. "Because you could see crystal-clear water coming down a hillside [and running into a waterbody] and think it was fine, when actually it was quite laden with dissolved phosphorus." Coale's research also indicated that phosphorus might be able to leach into groundwater in areas with sandy soils--exactly the conditions of the Delmarva Peninsula.

Responding to this new information, extension agents went to Delmarva farmers who had been following recommendations on the application of nutrients and told them that their management plans were potentially causing environmental problems. "Most of the farmers were adaptable and were willing to listen to our new suggestions, though," says extension agent Ted Haas, who gathered with groups of farmers at countywide meetings to inform them of a whole new set of recommendations. "These were guys I worked with for 20-some years ... We [the extension service] were a trusted resource for Maryland farmers."

Finding Solutions

Soil erosion and nutrient runoff from agricultural land on Maryland's Eastern Shore is thought to have a direct impact on the water quality of the Chesapeake Bay. University of Maryland soil specialist Frank Coale helps to identify soils that are excessively rich in phosphorous, much of which comes from poultry litter produced by the region's extensive poultry operations.

More recent research by Coale involves analysis of soils that over time have accumulated very high levels of phosphorus. Working with colleagues in the university's Department of Natural Resource Sciences and Landscape Architecture, Coale has developed a phosphorus site index that helps identify areas where there is a danger of phosphorus loss from runoff as well as leaching into groundwater sources. "We recently developed criteria that can help farmers determine with a good degree of accuracy at what point their land is in danger of becoming over-saturated with phosphorus," he says.

The phosphorus site index--available to Maryland farmers both in print and electronically on CD--identifies a fairly simple set of soil characteristics, yet it is actually quite sophisticated, Coale says. The characteristics identified in the index include the erosion potential of the site, the contours of the land and the types of soil in the area. "We categorize these factors and take soil samples," he says, "and then look at the manure content or the fertilizer content that is added to the landscape. We also look at the basic management of the land ... Is the poultry manure being plowed in, or is it left on the soil surface?"

The index can then be used to rate whether the sampled area is low-, medium- or high-risk in terms of phosphorus runoff, which in turn allows university soil specialists and extension agents to recommend ways for farmers to better manage their waste applications and soil conditions. Solutions range from suggesting that farmers decrease the levels of poultry litter applied; to bioremediation techniques aimed at "pulling" excess phosphorus from the soil; to recommending that no nutrients of any kind, whether from poultry litter or commercial fertilizer, be applied to the ground, sometimes for a period of several years. Other University of Maryland researchers are helping to lower risks of phosphorus overloading by reducing the amount of nutrients in poultry litter. Rosalina Angel, an assistant professor in the Department of Avian and Animal Sciences, is engaged in research that alters the diet of chickens to decrease the levels of phosphorus in the birds' excreta. Broilers, she says, and particularly young, rapidly growing birds, fail to digest more than half of the phosphorus from plant sources such as corn and soy. This is one key reason for high levels of phosphorus in the manure.

Dietary supplements for young broilers help to decrease phosphorus in the birds' excreta. Rosalina Angel, assistant professor of avian and animal sciences, also studies varying the feeding schedules of the young birds. Besides broilers, the Delmarva poultry industry produces eggs.

But before she could decrease the amount of phosphorus intake for broilers, Angel first needed to determine exactly what the phosphorus requirements were for the birds. A certain amount of phosphorus in chicken feed is necessary to promote growth and bone development and strength. Angel closely examined previous research that had set out specific feeding requirements for poultry at different stages of growth. "What we initially found out," she says, "was that if you don't know exactly what the phosphorus requirements are, that birds tend to be overfed on phosphorus."

Phytase, an enzyme added to the diet that helps the chicken utilize more phosphorus, was one area of the bird's diet that Angel looked at very carefully. Other feed additives that make phosphorus available to chickens were also studied. The use of phytase and other feed additives has proven useful in decreasing the amount of phosphorus that has to be mixed into the feed. This results in reduced levels of phosphorus in poultry manure, in some cases by as much as 40 percent.

Currently, Angel's research involves feeding broilers a combination of phytase and vitamin D metabolites, both of which are readily available to commercial growers. Her research takes into account how much commercial poultry producers are willing to adapt to new feeding schedules and additives. "We wanted productivity [feed costs and cycles] to remain unchanged ... and we also knew that industry would not accept bone breakage or bone chips [due to a change in diet] at the processing plant, which is a food-quality issue," Angel says.

Other Alternatives

As a biological resource engineer, Lewis Carr continuously looks for alternative uses for Delmarva poultry litter. Carr is an expert on different methods of composting poultry litter, which is then used in commercial landscaping or in Maryland's rapidly growing horticulture industry. There also is great interest in the burning of poultry litter as a fuel source, Carr says. He mentions a new facility on the lower Eastern Shore that takes poultry litter and processes it into pellets for combustion or to ship to other states for use as fertilizer. Carr says that the pelletization plant is planning to burn poultry litter pellets as the sole means to power the entire facility.

Carr and other researchers at the university have also helped define state guidelines for a program that removes poultry litter in bulk from the lower Eastern Shore and ships it to farms on the upper Eastern Shore where the soil is less saturated with phosphorus. The poultry litter transport project--a joint effort between the state of Maryland and poultry processors--provides cost-share of up to $20 per ton to offset the cost of transportation and handling of poultry litter from farms with excess litter. "A lot of that data came directly from University of Maryland soil test laboratories," Carr says. "By giving an accurate assessment of the soil needs on the upper shore, we were able to offer valid recommendations that resulted in the state helping farmers move the excess litter to areas of the state that can use it."

Legislating an Outcome

While there never was a definitive scientific link between excess phosphorus from the Delmarva poultry industry and the 1997 Pfiesteria occurrence, public opinion prompted a legislative response. In 1998, the Maryland General Assembly passed the Maryland Water Quality Improvement Act, which requires that every agricultural operation in the state with more than $2,500 in annual revenue have a written nutrient management plan. Part of the legislation is set to take effect this year, with farmers required to have a nitrogen-based nutrient management plan on file.

"Certainly there was some negative response ... The farmers didn't necessarily like more government regulation with the state telling them that they had to have a plan." says Doug Parker, an associate professor of agricultural resource economics at Maryland. "And they also didn't want to sign a paper that gives the state a right to come on their land and do inspections." Parker worked directly with the Maryland Department of Agriculture and the U.S. Department of Agriculture to help define guidelines for the legislation. "I wanted to help introduce flexibility into some of these new regulations ... Rather than telling the farmer 'you have to do this,' I wanted instead to set goals and let them find the best way to do that--giving the farmer some flexibility in the way to make those decisions," he says.

The university's extension service has nutrient management consultants in each county within the state to help farmers meet the requirements of filing a written plan, Parker says, and the university provides training for people who wish to become certified nutrient management consultants.

"The basic premise of a nutrient management plan is to provide information that is used to increase profits--whether that is by decreasing fertilizer costs or by increasing output," Parker concludes. "So the nutrient management work we do here looks both at increasing profits and also at meeting environmental goals of the state of Maryland. Through these types of programs, the College of Agricultural and Natural Resources seeks to protect water quality in the Chesapeake Bay while maintaining the state's vibrant agricultural economy."