Ökobilanz von Danone Activia-Verpackungen aus ... - Foodwatch

IFEU-Heidelberg Ökobilanz von Danone Activia-Verpackungen 2011 149
Table 1 Relative Global Warming Potentials for different annual crop (corn-soybean-wheat) management systems based on soil
carbon sequestration, agronomic inputs and trace gas fluxes. Units are CO2 equivalents (g/m 2 /year), using IPCC conversion
factors. Negative values indicate global warming mitigation potential through in situ soil sequestration.
Corn-soybean-wheat
rotations
I. Conventional inputs
+ tillage
II. Conventional inputs
+ No-till
III. Reduced inputs +
legume cover + tillage
IV. Organic inputs +
legume cover + tillage
CO2
Soil C
CO2
N fert.
CO2
Lime
CO2
Fuel
Endbericht – Bearbeitungsstand 29. März 2011
N2O CH4 Net
GWP
0 27 23 16 52 -4 114
-110 27 34 12 56 -5 14
-40 9 19 20 60 -5 63
-29 0 0 19 56 -5 41
The study supports a conclusion that all the studied non-conventional tillage systems
increased soil carbon over the decade-long period of the study. This soil carbon
accumulation even characterized the low-input and organic regimes despite the use
of plowing/tilling techniques. In those two cases, the sequestered carbon is likely the
result of the winter cover crop adding unharvested plant biomass to the soil. None of
the cropping systems provided a net reduction in greenhouse gas emissions.
However, no-till conservation tillage performed best in reducing contributions to
global climate change. The no-till system accumulated 30 g C or 110 g CO2/m 2 /year,
which is an average value for no-till rotations in the Mid-west United States.
The average accumulation of carbon in the soil in the twenty-six counties surrounding
the Cargill/NatureWorks production facilities can be estimated at 16 g C/m 2 /year. This
is equivalent to a carbon dioxide fixation of 59 g CO2/m 2 /year.
In light of this data, the following assumptions were made:
- conservation no-till practices are applied on 35.8% of the corn acreage‟s. Soil
carbon accumulation is assumed to be 30 g C/m 2 /year (Case II of Table 1).
- conventional till practices are applied on 15.4% of the corn acreage‟s. The soil
carbon accumulation for these areas is assumed to be 0 g C/m 2 /year (Case I of
Table 1).
- For the remaining acreage (48.7%), it is assumed that mulching and reducing
tilling are practiced, with a soil carbon accumulation of 10.9 g C/m 2 /year (Case III
of Table 1).