by Bill Schlesinger
“Boys, I may not know much, but I know chicken shit from chicken salad.”
– Lyndon B. Johnson
North Carolina, long known for embracing concentrated animal feeding operations (CAFOs), especially for hogs, has welcomed the burgeoning industrialized production of chickens. Of course, we all embrace chicken—the meat is healthier than beef and produces less impact on the climate. Something on the order of a billion chickens are now housed in North Carolina. With each bird responsible for about 0.10 lbs of nitrogen in chicken waste each year, that amounts to a lot of nitrogen, largely found as ammonia and uric acid, in their wastes.
Duplin County is the top poultry-producing county in the North Carolina. In 2020 it sold 9.1 million broiler chickens, 3.45 million turkeys and had 480,000 laying hens. When you add up all the chicken waste in Duplin County, poultry excreted 4225 tons of nitrogen in manure in 2020, while the 48,515 humans in the County put less than 244 tons of N in the toilet. Poultry manure produces more than 17 X as much waste N as all the people in Duplin County. There are no established regulations for disposal of poultry wastes. Some is returned to farm fields, but its acidic nature is not always helpful to plant growth.
At a larger scale, one billion chickens in North Carolina produce nearly 50,000 tons of nitrogen in their wastes annually. For comparison, 873,570 people in the city of Charlotte (assuming they have average poops and that the total nitrogen content in their poop and pee is 12.5 g N per day) excrete about 4389 tons of N per year.
Chicken feed, grown locally or imported from Mid-western states like Iowa, is the source of all the nitrogen that chickens excrete. When it is subject to runoff to surface streams, nitrogen in manure is a major water pollution problem in North Carolina and Chesapeake Bay in Maryland. Nitrogen in manure is converted to ammonia gas, which exacerbates air pollution problems by forming fine particles (<2.5-micron diameter) in the atmosphere. Chicken manure is also associated with several fungal-borne diseases, transported by air, and poultry farms are a major local source of obnoxious odors, which lower property values and the health of nearby citizens.
Housing a billion chickens in North Carolina is equivalent to living with 10,000,000 more people with no sewage treatment. Can we tolerate that?
References:
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Baker, J., W.H. Battye, W. Robarg, S.P. Arya and V.P. Aneja. 2020. Modeling and measurement of ammonia from poultry operations: Their emissions, transport and deposition in the Chesapeake Bay. Science of the Total Environment 706: 135290
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Grijalva, D.F.M. et al. 2010. Nitrogen, phosphorus, and liming effects of poultry layer manures in coastal plain and piedmont soils. Agronomy Journal 102: 1329-1339
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