Treating Poultry Litter with Aluminum Sulfate (Alum)
Aluminum sulfate (alum) is added to poultry litter in the poultry house to reduce soluble phosphorus.
Poultry litter contains high concentrations of water soluble phosphorus. Research has shown that phosphorus runoff is closely related to the soluble phosphorus content of manure. Alum additions to poultry litter reduce soluble phosphorus into forms that are much less water soluble. This greatly reduces phosphorus runoff from fields fertilized with poultry litter, as well as phosphorus leaching. Alum additions also reduce ammonia emissions from poultry litter. Lower ammonia levels in poultry houses result in heavier birds, better feed conversion, lower condemnation, and lower mortality. Lower ammonia levels result in lower ventilation requirements, which results in much less propane being used for heating during cooler months. Lower propane use results in significantly lower carbon dioxide emissions from poultry houses. Alum additions also reduce the number of pathogens in litter.
How Does This Practice Work?
Alum should be applied to poultry litter at a rate equivalent to 5-10 percent by weight (alum/manure). For typical broiler operations growing 6-week-old birds, this is equivalent to adding 0.1 to 0.2 pound alum per bird, or 1-2 tons of alum per house per flock if 20,000 birds are in each house.
Aluminum from alum reacts with inorganic and organic phosphorus to form insoluble aluminum phosphate compounds that are far less susceptible to runoff or leaching. The reduction in ammonia emissions is due to the acid produced when alum is added to the litter. This acid converts ammonia to ammonium, which is not subject to volatilization. The reduction in litter pH also causes pathogen numbers to decrease.
Where This Practice Applies and Its Limitations
This practice applies to all poultry operations that have dry litter (broiler, breeder and turkey houses). Reduction in soluble phosphorus may not occur if the poultry litter has been previously treated with sodium bisulfate, which is sold under the tradename PLT (Poultry Litter Treatment), due to the formation of sodium aluminite, which inactivates the aluminum with respect to phosphorus adsorption or precipitation reactions.
Treating poultry litter with alum is one of the most effective methods of reducing phosphorus runoff from fields fertilized with litter. Alum applications to poultry litter have been shown to reduce phosphorus runoff by 87 percent from small plots and by 75 percent from small watersheds.
Alum additions also result in less nitrogen being lost due to ammonia volatilization. Ammonia emissions from alum-treated litter have been shown to be about 50 percent lower than untreated litter. This results in a higher nitrogen content of the litter, which boosts crop yields. Lower ammonia levels in the rearing facilities also improve poultry production and make the environment safer for agricultural workers. Reducing atmospheric ammonia emissions will also result in less air pollution, such as particulate matter less than 10 microns (ammonia is a precursor to PM-10s), atmospheric nitrogen deposition, and soil acidification.
The long-term effects of applying alum-treated litter to land have indicated that this practice is sustainable. Soluble phosphorus levels in soils fertilized with alum-treated litter are significantly lower than that in soils fertilized with normal litter. Hence, there is less phosphorus leaching with alum-treated litter. Long-term studies have also shown that exchangeable aluminum levels in soils fertilized with normal and alum- treated litter are low (less than 1 mg Al/kg soil) and are not significantly different, whereas plots fertilized with the same amount of nitrogen from ammonium nitrate have very high exchangeable aluminum (up to 100 mg Al/kg soil). Results from long-term studies indicated that tall fescue yields were highest with alum-treated litter, followed by normal litter and lowest with ammonium nitrate.
Cost of Implementing the Practice
Treating poultry litter with alum is a cost-effective conservation practice, due to the economic returns from improved poultry production and reduced energy costs. The three main forms of alum are dry alum, liquid alum (48.5% dry alum equivalent by weight) and acid alum (36.5% dry alum equivalent by weight). In 2023, dry alum costs about $550 per ton, liquid alum about $200 per liquid ton and acid alum about $120 per liquid ton. To add the equivalent of one ton of dry alum, 370 gallons of liquid alum or 512 gallons of acid alum are needed. At present most growers are utilizing liquid alum because most custom applicators are set up for applications of liquid alum. However, if the distance to a liquid alum manufacturer is great, then dry alum should be used since shipping costs are lower.
As mentioned earlier, two tons of dry alum equivalent should be applied to a typical broiler house after each flock. Research conducted in the 1990s showed that the economic returns from this practice were $308 for the grower and $632 for the integrator (company), for a combined return of $940. This was almost twice what the cost was at that time to treat a house with two tons of alum ($500), resulting in a benefit/cost ratio approaching 2. Although the price of alum has doubled since that time, the cost of poultry, poultry feed (mainly corn and soybeans) and propane have more than doubled since then.
Operation and Maintenance
Alum is normally applied between each flock of birds. Dry alum can be applied with a number of different spreaders, such as decaking machines, fertilizer spreaders, manure spreaders or drop spreaders. Applicators should always wear goggles for eye protection and a dust mask to avoid breathing alum dust.
Gloves should also be worn to prevent skin irritation. To ensure the chickens do not consume the granules of alum, it is best to till the product into the litter. This can be done with a litter decaker or with any other device that physically mixes alum into litter. Liquid alum is normally only applied by a certified professional applicator. Acid alum is preferred in situations where the litter is very dry since it activates quickly.
Anderson, K.R., P.A. Moore, Jr., D.M. Miller, P.B. DeLaune, D.R. Edwards, P.J.A. Kleinman, and B.J. Cade-Menun. 2018. Phosphorus leaching from soil cores from a twenty-year study evaluating alum treatment of poultry litter. J. Environ. Qual. 47:530-537.
Eugene, B., P.A. Moore, Jr., H. Li, D. Miles, S. Trabue, R. Burns, and M. Buser. 2015. Effect of alum additions to poultry litter on in-house ammonia and greenhouse gas concentrations and emissions. J. Environ. Qual. 44:1530-1540.
Huang, L., P.A. Moore, Jr., P.K.J. Kleinman, K. Elkin, M. Savin, D. Pote, and D.R. Edwards. 2016. Reducing phosphorus runoff and leaching from poultry litter with alum: Twenty year small plot and paired watershed studies. J. Environ. Qual. 45:1413-1420.
Moore, P.A., Jr. 1997. Use of alum to inhibit ammonia volatilization and to decrease phosphorus solubility in poultry litter. U.S. Patent 5,622,697. Issued April 22, 1997.
Moore, P.A., Jr. 1999. Methods for decreasing non-point source pollution from poultry manure. U.S. Patent 5,928,403. Issued July 27, 1999.
Moore, P.A., Jr. 2011. Improving the sustainability of animal agriculture by treating manure with alum. In He, Z., (ed.) Environmental Chemistry of Animal Manure. Nova Science Publishers, Inc., Hauppauge, NY. Pp. 349-381.
Moore, P.A., Jr., S. Watkins, D.C. Carmen and P.B. DeLaune. 2004. Treating poultry litter with alum. University of Arkansas Cooperative Extension Fact Sheet (FSA8003-PD-1-04N).
Moore, P.A., Jr, T.C. Daniel, and D.R. Edwards. 1999. Reducing phosphorus runoff and improving poultry production with alum. Poultry Sci. 78:692-698.
Moore, P.A., Jr, T.C. Daniel, and D.R. Edwards. 2000. Reducing phosphorus runoff and inhibiting ammonia loss from poultry manure with aluminum sulfate. J. Environ. Qual. 29:37-49.
Moore, P.A., Jr., and D.R. Edwards. 2005. Long-term effects of poultry litter, alum-treated litter, and ammonium nitrate on aluminum availability in soils. J. Environ. Qual. 34:2104-2111.
Moore, P.A., Jr., and D.R. Edwards. 2007. Long-term effects of poultry litter, alum-treated litter, and ammonium nitrate on phosphorus availability in soils. J. Environ. Qual. 36:163-174.
Shreve, B.R., P.A. Moore, T.C. Daniel, D.R. Edwards, and D.M. Miller. 1995. Reduction of phosphorus runoff from field-applied poultry litter using chemical amendments. J. Environ. Qual. 24:106-111.
For Further Information
Contact your local soil and water conservation district, USDA-NRCS or Cooperative Extension Service office. To find your local USDA Service Center, visit https://www.nrcs.usda.gov/contact/find-a-service-center.
|Philip A. Moore, Jr.
Editing and Design
NC State University
University of Tennessee
Moore, P.A., Jr. 2023. Treating Poultry Litter with Aluminum Sulfate (Alum). SERA17 Phosphorus Conservation Practices Fact Sheets. https://sera17.wordpress.ncsu.edu/treating-poultry-litter-with-aluminum-sulfate/