Agricultural Engineering Research, Volume 8 (2002)

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Browsing Agricultural Engineering Research, Volume 8 (2002) by Person "Gallmann, Eva"

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    Environmentally Compatible Fattening Pig Husbandry II : Comparison of Emission Rates
    (2002) Gallmann, Eva; Hartung, Eberhard; Jungbluth, Thomas
    During the course of continuous emission measurements of ammonia (NH3 ), carbon dioxide (CO 2 ), and methane (CH4 ) for the evaluation of the environmental impact of housing systems for fattening pigs, a fully slatted floor system with forced ventilation (FSF) and a kennel housing system with natural ventilation (KN) were examined. Through long-term measurements over four consecutive fattening periods from October 1999 until April 2001, enough data from different seasons and fattening stages were gained on the one hand, while on the other hand it was pos- sible to carry out a comprehensive verification of data along with selec- tion based on clear verification criteria. For the comparison of the emis- sion rates on the basis of the daily mean values, approximately 60% of the measuring days and of the data were taken into account. Stocking (in livestock units) and the liquid manure parameters as mar- ginal conditions did not exhibit any significant differences between the housing systems FSF and KN. With increasing fattening duration and liquid manure quantity, an increase in the ammonium-nitrogen content of the liquid manure from approximately 2 to 5 g/kg in the fresh substance was recorded. The air temperature and relative humidity in the interior of the system KN largely followed the outside conditions. In principle and also on warm days, the interior temperatures ranged below the values for the FSF system. However, the opposite was true for relative humidity, which clearly exhibited higher values in the KN system. Due to the differ- ent modes of operation of the ventilation systems, clear differences could also be discerned between the housing systems, especially in the winter when the air flow rates in the KN systems were 2 to 4 times higher as compared with the winter air flow rate of forced ventilation in the FSF system, for example. The gas concentrations in the exhaust air of the FSF system generally exhibited significantly higher values. On all measuring days considered, the daily mean values of the NH3 , CO2 , and CH4 emis- sion rates [(g/d)*LU-1 ] for the KN system were lower by a factor of ap- proximately 1.5 as compared with the FSF system. The comparison of the average emission rates per fattening period between the housing systems showed a very significant difference in favour of the KN housing system. During the four observed fattening periods, the mean value of the NH 3 emission rate for one fattening period varied between 67 and 96 (g/d)*LU-1 in the KN system and between 100 and 149 (g/d)*LU-1 in the FSF system. The CO2 emission rates ranged between 10 to 13 (kg/d)*LU-1 (KN) and 17 to 23 (kg/d)*LU-1 (FSF). In the KN system, the mean values of the CH4 emission rates per fattening period (17 to 36 (g/d)*LU-1 ) were also lower than in the FSF system at 62 to 134 (g/d)*LU-1.
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    Environmentally Compatible Fattening Pig Husbandry III : Daytime-Related Effects
    (2002) Gallmann, Eva; Hartung, Eberhard; Jungbluth, Thomas
    As part of continuous emission measurements in the experimental stall for fattening pigs in Hohenheim, a conventional stall with fully slatted floor and forced ventilation (FSF) was compared with a naturally ventilated kennel housing system (KN) during four fattening periods from October 1999 until April 2001. The third contribution to the article series about environmentally compatible fattening pig housing focuses on the description and analysis of daytime-related effects and the course of emissions. The courses of three measuring periods during the second fattening period which were chosen as examples as well as multiple regression analyses were studied to answer the question of what variables mainly determine the different daily courses of NH3 - and CO2 -emission and to what extent emission reduction strategies may influence the daily course. In accordance with the literature, the FSF housing system largely showed a positive correlation between temperature, volume flow, and emission. In the KN housing system, however, a reduction in emissions was observed combined with increasing volume flows, which generally occurred in particular at low temperatures. Animal activity, which was strongly influenced by the feeding times, was reflected by significant peaks of CO 2 concentration and –emission as well as NH3 emission. In the FSF housing system, the percentage of variance in the daily course of the emission rates during the selected measuring periods which can be explained through variables able to be used for practicable stall climate recording and –control and able to be influenced through measures of emission reduction ranged between 12 % and 75 % for NH3 and between 39 % and 47 % for CO2 . In the KN housing system, the percentage of explainable variance is lower at 52 % to 64 % (NH3 ) and 18 % to 28 % (CO2 ).