Humic Manure Additive Reduced Odor from Pennsylvania Swine Finishing Operation.

With encroaching population into rural areas, odor-related nuisance complaints regarding collection, transport and land application of animal manure threaten the livelihood of animal production facilities. Studies to date show highly variable efficacy of manure amendments or limited success in reducing odors. Direct sensory methods (field and laboratory-based olfactometry) using qualified human assessors to evaluate odors from two similarly-operated but widely separated 2,250-pig, tunnel-ventilated barns on a swine finishing farm were used to demonstrate the effectiveness of a commercial, humic-based additive. Five monthly shock-treatment applications each used 3.3 gal of amendment per 1,000-ft² of manure pit surface area during the 20 week grow out cycle in the first barn while the other barn was untreated and served as a control. During the second grow out period barn treatments were switched. Barn exhaust fan odor flux rates were reduced by 21% (odor units/min, P < 0.001) for both field and laboratory odor assessment methods. Land application manure-ring odor dilution to threshold (D/T) and detection threshold (DT) concentration levels were reduced by 21% (P = 0.15) and 60% (P < 0.001) for field and laboratory assessment methods, respectively. This odor reduction level may not be readily discernable at the source by all people. However, dilution at distance from the source (e.g. at the property line) could reduce nuisance odor complaints, especially when combined with other odor mitigation practices.