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Gaseous Emissions From Aviaries And Nitrogen And Phosphorus Losses In The Outdoor Run Of Organic Laying Hens

Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan

Citation:  2012 IX International Livestock Environment Symposium (ILES IX)  ILES12-0731.(doi:10.13031/2013.41642)
Authors:   Sanne (S.E.M.) Dekker, Peter (P.W.G.) Groot Koerkamp, André (A.J.A.) Aarnink, Imke (I.J.M.) De Boer
Keywords:   Organic farming, laying hens, environmental impact, ammonia, methane, nitrous oxide, manure, outdoor run, mineral load

Emissions and losses from animal production systems cause substantial environmental impact, e.g. eutrophication, acidification and global warming. The objectives of this study were to assess the year round emissions of ammonia (NH3), nitrous oxide (N2O), and methane (CH4) from commercial aviary systems with organic laying hens and to determine the level and variation of the total mass, and load of nitrogen (N) and phosphorus (P) excreted into the outdoor run of three commercial organic laying hen farms. Emissions were computed from the ventilation rate (CO2 mass balance) and gas concentrations. N and P losses were calculated from number of hens, mass and content of excrements in the outdoor run. Mean emission per hen was 410 mg d-1 for NH3, 3.12 mg d-1, for N2O and was 81.7 mg d-1 for CH4. Mean predicted emission of NH3 per hen on the first day after manure removal was 298 mg d-1, and increased by 5.47% d-1. Using aviary systems in organic laying hen husbandry instead of single-tiered systems has the potential to reduce emissions of NH3, N2O, and CH4. Mean percentage of hens outside was 1.7% on farm 1, 16.0% on farm 2 and 7.1% on farm 3 and. On all farms load of N and P heavily exceeded the fertilization standard of 170 kg ha-1 y-1 and decreased exponentially with increasing distance from the hen house, due to an also exponentially decreasing hen density.

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