Date of this Version
The percentage of feedlot feces and manure P that is water soluble was 41% (not accounting for additional soluble P from urine) and 24% respectively. The interaction of feces and urine with minerals and metals reduced the water solubility of P in feedlot manure relative to feces. Increasing dietary P level increased manure P concentration and water solubility of manure. Manure P from cattle fed feedlot diets containing 0.30% to 0.50% P was 28% water soluble P. The water solubility of P in feedlot feces and manure is an indicator of the potential for P runoff from feedlots and fields receiving manure.