Influence of environmental factors and the addition of wood shavings on ammonia and odour emissions from fresh livestock manure

Abstract

N. M. Ngwabie, K.-H. Jeppsson, G. Gustafsson, S. Nimmermark

(Department of Rural Buildings and Animal Husbandry, Swedish University of Agricultural Sciences,

P.O. Box 86, S-230 53 Alnarp, Sweden)

Abstract: Gaseous emissions from livestock manure may adversely affect human and animal health as well as the surrounding environment.  In an effort to understand and mitigate these emissions, the effects of different environmental factors and the addition of wood shavings on ammonia and odour emissions from fresh pig and dairy cow manure were studied.  The manure was divided into two portions and wood shavings (25% pine and 75% spruce) were mixed with one portion.  Emissions from equal volumes (0.009 m³) of both portions were measured at different environmental conditions in a flux chamber.  The manure temperature was varied between 15 – 30 ^ºC.  Fresh air at temperatures between 16 – 26 ^ºC was passed at a fixed rate over the manure.  The addition of wood shavings decreased the total-N and NH₄⁺-N, but increased the pH of the manure at the end of the experiment.  The temperature of the manure with wood shavings increased faster than that of the manure without wood shavings.  The ammonia emission from the pig manure (0.08 – 0.41 mg m^-2 s^-1) was on average much higher than the ammonia emission from the cow manure (0 – 0.08 mg m^-2 s^-1).  The odour emission from the pig manure was high (21 –   930 OU m^-2 s^-1), and significantly higher than the odour emission from the cow manure (1–6 OU m^-2 s^-1).  A positive correlation was found between the ammonia emissions and the manure temperature.  Ammonia emissions were about twice higher at manure temperatures of about 25 ^ºC than emissions at about 15 ^ºC.  Odour emissions were positively correlated with the temperature of cow manure.  Ammonia emissions at 25 ^ºC were high, while odour emissions at 25 ^ºC were lower than those at 20 ^ºC for the pig manure with wood shavings.  The emissions from the cow manure but not from the pig manure were positively correlated to the water vapour pressure.  The measurements indicated a positive correlation between ammonia and odour emissions for the cow manure as well as for the pig manure without wood shavings.  The addition of wood shavings to animal manure does not seem to automatically mitigate ammonia or odour emissions as it also affects the temperature and the pH.

Keywords: dry matter, C/N ratio, volatilization, temperature, ammonium, Sweden

Citation: Ngwabie N. M, K.-H. Jeppsson, G. Gustafsson, S. Nimmermark.  Influences of environmental factors and the addition of wood shavings on ammonia and odour emissions from fresh livestock manure.  Agric Eng Int: CIGR Journal, 2010, 12(3): 68-81.