Phosphorus control may be key UM researching ways to reduce content in chicken manure

Fish kills

September 25, 1997|By Ted Shelsby | Ted Shelsby,SUN STAFF

Chicken manure just might be one of Mother Nature's best fertilizers.

It is also one of the cheapest.

As Coulbourne Swift figures it, he can save up to $50 an acre by spreading chicken manure over his farm rather than using chemical fertilizer.

"Now, that may not sound like much," said the Somerset County chicken grower and grain farmer, "but when you multiply that by 3,000 acres, you're talking about a big chunk of money.

"That's our livelihood," he said of the savings.

But a problem with manure, according to state Agriculture Secretary Lewis R. Riley, is that when farmers spread enough of it on their fields to get the needed amount of nitrogen, they are greatly exceeding the recommended phosphorus levels.

"Almost everybody exceeds the phosphorus level," said Riley, a poultry farmer himself.

And phosphorus is a prime suspect in stimulating the microbe Pfiesteria piscicida, which has been blamed for fish kills in two Eastern Shore rivers and one creek; causing human illness and rendering a staggering economic blow to Maryland's giant recreational fishing and seafood industry.

Thomas Fretz, dean of the University of Maryland, College Park's College of Agriculture and Natural Resources, said the school is involved in research into ways of solving the phosphorus problem.

The efforts are headed by Frank J. Coale, and they range from changing the way farmers use manure to changing the diet of chickens.

Coale, a 38-year-old associate professor involved in soil fertility and nutrient management, was one of a half-dozen people who testified yesterday at a meeting of the commission on Pfiesteria headed by former Gov. Harry R. Hughes.

He told the 11-member panel that phosphorus levels in the soil have risen greatly over the past 30 years, and land on the lower Eastern Shore has the highest levels.

In an earlier interview, Coale said that, based on the university's soil tests, the typical Eastern Shore farm needs anywhere from zero to 40 pounds of phosphorus per acre for healthy plant growth. But farmers, he said, are applying anywhere from four times to 100 or more times that amount.

"We're looking at a number of ways of reducing the amount of phosphorus spread on fields that could run off into the waterway," he said. They include:

Having farmers switch from a nitrogen-based nutrient management system to a phosphorus-based plan.

Under this arrangement, Coale said, farmers would apply only enough manure to provide the phosphorus that plants need. Any needed additional nitrogen would come from chemical fertilizer.

A problem with this, he said, is that it would increase farmers' production costs. There would also be excess manure to be hauled away -- also at additional cost.

Changing the diet of chickens. Coale said an enzyme called phytate could be added to chicken meal by processors. "It would help improve the digestion of phosphorus by chickens and they would excrete less of it," he said.

Coale said early tests at the university's experimental chicken farm in Upper Marlboro are encouraging. "There are indications that it could work."

Genetically altering the structure of corn so that more of the phosphorus would be digested by the chicken.

On Monday, Coale is scheduled to meet with a researcher of Des Moines, Iowa-based Pioneer Hi-Bred International Inc. at Wye Mills to discuss the potential of the experimental corn.

"We will have to see if you can grow it in this part of the country and have a quality crop," he said. "Then we will test to see if there is a significant reduction in the nutrient level of the manure."

Mixing aluminum sulfate with the manure to trap the phosphorus before it runs off.

Coale said the chemical acts like a magnet and combines with the phosphorus in the manure to keep it from running off the field. "This doesn't reduce the amount of phosphorus," he said, "It just traps it on the field."

Fretz, the university dean, also raised the possibility of using genetic engineering to alter the intestines of chickens so that they would digest more of the phosphorus in their feed.

"A number of things are possible," he said, "but we are going to need more funds for research."

Coale said he is operating on a budget of about $100,000 a year, and half of it is used for phosphorus research. The bulk of the funding comes from voluntary contributions from the state's grain farmers and poultry producers.

He said the Pfiesteria scare has focused much more attention on the university's efforts, "but I have not seen any additional dollars yet."

Fretz warned of other economic consequences of the Pfiesteria problem.

"There are many in this state who could care less about the poultry industry," he said. "They say, 'You can get these chickens and get them off our beautiful Eastern Shore.'

"Well, then you are going to have an economy of rural poverty in that part of the state. What is going to replace an industry that generates almost $1.5 billion a year in direct economic activity and $4 billion to $5 billion indirectly?"

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