Tackling the future challenges of Organic Animal Husbandry - vTI

Introduction
RAHMANN G & GODINHO D (Ed.) (2012): Tackling the Future Challenges of Organic Animal Husbandry.
Proceedings of the 2 nd OAHC, Hamburg/Trenthorst, Germany, Sep 12-14, 2012
Animal Husbandry and Climate Change in
Organic Production Systems
ANDRE LEU
President, IFOAM
email: a.leu@ifoam.org
The methane output from animal husbandry systems is considered a major contributor to global
greenhouse gases (GHGs) emissions. The science on soil methane and soil organic matter is still in
its infancy, with many unanswered questions due to the lack of research. This paper will look at
some of the emerging areas of research that question the current models used to assess animal husbandry
systems and show that extensive organic pasture based systems have the ability to be net
sequesters of GHGs rather than net emitters.
Methane Emissions and Degradation
Historically, apart from a few exceptional events during geological time periods, the amount of methane
in the atmosphere from the enormous herds of grazing animals on the prairies, savannahs and
steppes, and from the decay of organic matter in the vast forests and wetlands of the planet was relatively
stable until human activities over the last 200 years disrupted the natural cycles of methane
production and degradation (Heimann, 2011, Murat A et al, 2011).
Studies by Hellebrand and Herppich (2000) and Levine et al. (2011) showed that a significant
amount of methane is biodegraded in soils, and that this has been underestimated due to lack of
research. A study by van Groenigen et al.(2011) shows an increase in methane output from soils
when the temperature increases, however the Hellebrand and Herppich studies show that the increase
in temperature will drive up the rate of biological degradation of methane by methylotropic
bacteria and other methanotrophic micro-organisms. This could explain why historical atmospheric
methane levels have been relatively stable, and also why naturally produced atmospheric methane
levels may not increase as the climate gets warmer.
Many studies of methane production only calculate the methane produced by the systems as a oneway
output into the atmosphere. This can be correct for some production systems, such as confined
animal feed lots and garbage sent to land fill; however, it is not correct for most natural productions
systems, such as animal grazing on grasslands, crop production on biologically active soils, orchards
and forests, as these systems are based on cycles that also degrade methane. This oversight
of the amount of methane that can be biodegraded by the soil or the oceans is a major flaw that
needs to be rectified.
Until the decay cycles are properly identified, measured and modelled, the amounts of methane that
are given out by animal husbandry systems are not an accurate measure of these systems methane’s
contribution to total GHGs.
The Need for Good Soil Management Practices to Reduce Methane Emissions
A study by Fuu Ming Kai et al. (2011) suggests that the recent reductions in methane output are due
to changes in farming practices. This study adds to the data showing that there is good evidence of
the potential to reduce the amount of methane in the atmosphere through good soil management
practices.
Understanding these cycles and the biological conditions needed to biodegrade methane will give
scientists and landholders a major tool to manage one of the most important GHGs.
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