Malodor-reducing effects of providing fulvic acid to growing pigs in drinking water and spraying fulvic acid in swine barns

The objective of the present work was to evaluate the malodor-reducing effects of spraying fulvic acid in swine barns and providing to growing pigs in drinking water. Fulvic acids for drinking and for spraying to barns were prepared at 0.02%, and fulvic acid for spraying to compost were prepared at 0.1%. Prepared fulvic acid of 1 L was sprayed to the test nursery pig barns twice a week but was not sprayed to the control barn. Fulvic acid at 0.02% for drinking was provided to growing pigs for 4 weeks but was not provided to the control group. In the experiment for spraying to compost, 3 additives consisted of 1) probiotics 0.08 L, 2) probiotics 0.04 L + fulvic acid 0.04 L, and 3) fulvic acid 0.08 L were tested by adding to the compost samples of 80 L in 100 L plastic bucket for each and directly adding to the mechanical agitated composting facility. As a result of spraying fulvic acids to nursery pig barns, ammonia concentration was not increased compared with the control barn in which ammonia increased continuously. Fulvic acid provided to growing pigs did not result in difference of excreted ammonia compared with the control group. Probiotics, probiotics + fulvic acid, and fulvic acid sprayed to the test compost resulted in reduced malodor and ammonia after agitation compared with before agitation (p < 0.001) with the greatest effects in the fulvic acid group among the 3 additives. Additionally, the temperature of compost receiving fulvic acid reached 40°C earlier than that of the control compost, which means that the time for primary fermentation of the compost was advanced by receiving fulvic acid. In conclusion, fulvic acid at 0.02% sprayed to pig barns and fed to pigs as water showed effective reduction of malodor, and fulvic acid at 0.1% sprayed to the compost reduced the time for primary fermentation and thus decreased the malodor.