Abstract

GUZMAN, M.L; VENECIANO, J.H  and  SAGER, R.L. Emisión de gases en un sistema ganadero intensivo. RIA. Rev. investig. agropecu. [online]. 2014, vol.40, n.3, pp.270-275. ISSN 1669-2314.

The environmental problems facing intensive fattening systems relate bovine animal metabolism and degradation of manure. The purpose of this work is to study the origin and factors that control emission and production of compounds causing odor and greenhouse gases (GHG). Questions were address in vitro (laboratory works) and in situ (field works) In vitro incubations of soil samples from a feedlot system were performed in the laboratory under different oxygen concentrations (aerobic and anaerobic), monitoring gas generation during 216 h. Field measurements were made at 4 random points within each area of the system (pens with and without animals, trap of solids, aerobic and anaerobic lagoons). The determinations of methane (CH4), carbon monoxide (CO) and carbon dioxide (CO2) and oxygen (O2) in both situations were performed with a portable detector Reike Keiki (RH -515) adapted to each individual case, probes were inserted within each experimental laboratory unit and closed field chambers. To control the production of feedlot odor, a commercial enzyme product was evaluated measuring the concentration of hydrogen sulfide (H2S), volatile organic compounds (VOC) ammonia (NH3) CH4 and CO2 with an Eagle 2 portable detector. In vitro gas production results showed significant difference for every gas; CO (p = 0.0189), CH4 (p = 0.0004), CO2 (p <0.0001) and O2 (p <0.0001). However, similar behavior was observed in both cases (lab and field) product of anaerobic or aerobic digestion, depending on the conditions prevailing at the time or the site, indicating the coexistence of both metabolisms in between. The highest levels found were 0.109 % LEL of CH4, CO= 22.27 ppm and 8.23 % CO2 for in vitro anaerobic conditions, and 0.468 % LEL of CH4 , 0.43% CO2, 7.21 ppm of NH3, 4.67 ppm of H2S and 14.54 ppm VOC for in situ natural conditions. Enzymatic treatment with a commercial product produced significant decrease in NH3 and VOC, unlike SH2 that increased. It is concluded that to do a good management of the emission of greenhouse gases and to control potentially polluting effluents, the problems should be address by more than one practice to suit local climatic conditions variables and heterogeneity of the meat production intensive system.

Keywords : Intensive livestock systems; Gaseous emissions; Measured in vitro; Measured in situ.

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