Ammonia volatilization from liquid hog manure amended with paper products in the laboratory

Losses of N from livestock operations due to ammonia (NH3) volatilization from animal wastes is a major source of pollution in Europe and North America, and represents a significant economic loss. Paper products have potential as amendments to reduce NH3 loss because their high carbon (C) and low nitrogen (N) contents would be expected to cause N immobilization. Reduction in NH3 volatilization from liquid hog manure (LHM) by paper bag (PB), filter paper (FP), newsprint (NP), and pulp sludge (PS) added at 2.5 and 5% (fresh LHM weight) was evaluated in a 56 d incubation study. Cumulative NH3 volatilization ranged between 28 and 53% of initial manure N. When the rate increased from 2.5 to 5%, NH3 volatilization was reduced by 47, 40, 37, and 29%, respectively, compared to the control. Increasing the rate increased the amount of C lost from the LHM and reduced the net mineralization of organic N. Hence, the addition of organic amendments appeared to have decreased NH3 volatilization by increasing microbial activity and N immobilization. Liquid hog manure pH was negatively correlated with C loss, indicating that microbial decomposition of paper amendments lowered manure pH but this effect did not appear to be important in controlling NH3 volatilization. Paper lignin content was not correlated with the loss of C, manure pH, or NH3 volatilization, suggesting that the effectiveness of paper products in reducing NH3 volatilization is not controlled by lignin content but rather by other more labile components.