Development of a New Manure Amendment for Reducing Ammonia Volatilization and Phosphorus Runoff from Poultry Litter

Adding alum to animal manures greatly reduces ammonia (NH3) emissions and phosphorus (P) runoff.  Improvements in poultry production, lower energy costs and environmental benefits from alum have led to widespread use by the poultry industry. Over one billion broilers are grown with alum in the U.S. each year.  However, the price of alum has increased dramatically, creating a need for cheaper products that control NH3 and P losses. The goal of this research was to develop an inexpensive manure amendment that is as effective as alum in reducing NH3 volatilization and P runoff from poultry litter. Sixteen manure amendments were created using various ratios of alum mud, bauxite ore, sulfuric acid, liquid alum and water.  Alum mud is the waste product that is left over from the manufacture of alum when made by mixing sulfuric acid with bauxite. A laboratory NH3 volatilization study was conducted using a total of 11 treatments; untreated poultry litter, litter treated with liquid or dry alum and litter treated with eight of the new mixtures. All amendments tested resulted in significantly lower NH3 losses than the controls. Ammonia losses with dry and liquid alum were reduced by 86% and 75%, respectively.  Ammonia losses with the eight new amendments ranged from 62 to 73% less than controls and were not significantly different from liquid alum and the three most effective mixtures were not significantly different from dry alum.  All of the amendments also significantly reduced water extractable P (WEP); three of which resulted in significantly lower WEP than with dry alum. The most promising products were mixtures of alum mud, bauxite, and sulfuric acid. The potential impact of these products could be enormous, since they could be produced for less than half the price of alum, while being equally effective at reducing both NH3 emissions and P runoff.


Moore, Philip        USDA/ARS

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