The buildup of excess phosphorus (P) in the soil resulting from previous applications of poultry litter referred to as “legacy P” is an environmental concern, since it acts as a continuing source of soluble P, which is the form contributing to accelerated eutrophication of waterbodies.
Adding alum to poultry litter is a best management practice (BMP) used to stabilize P in less soluble forms, reducing non-point source P runoff from fields. However, little research has been conducted on how alum additions to litter affect subsequent leaching of P from soil.
In a paper recently published in the Journal of Environmental Quality, researchers evaluated the effects of alum-treated versus untreated poultry litter on P leaching from soil cores taken from plots receiving poultry litter applications for 20 years. They found adding alum to poultry litter has a positive legacy effect on P; significantly reducing soluble P concentrations in leachate, by 83% compared with untreated litter.
This study suggests that the addition of alum to poultry litter can improve the sustainability of fertilizing with poultry litter.
Read the full article in JEQ. Free preview April 27 - May 4