Agriculture in Baden-Württemberg accounts for 58% of methane (CH4) and 78% of nitrous oxide (N2O) emissions (reference year 2017), making it the main emitter of these two greenhouse gases (GHGs). If past land use changes - essentially drainage and management of organic soils – and upstream emissions for e.g. mineral fertilizer production are included, agriculture is responsible for about 13-14% of total GHG emissions (on a CO2 equivalent basis).
The main sources of agricultural CH4 emissions are animal digestion in the ruminant stomach (80%) and farm manure management (20%). N2O from agriculture is predominantly emitted from soils (about 83%) - from the conversion (nitrification and denitrification) of mineral or organic nitrogen fertilizers and plant residues. In addition, there are nitrous oxide emissions from farm manure management and indirect emissions of N2O via other nitrogenous emissions to the atmosphere and hydrosphere as e.g. NH3, NO3- followed by their partial conversion to N2O.
The role of the "land use and land use change" (LULUC) sector should not be underestimated, which accounts for almost 30% of the total emissions from agriculture in Germany. This includes, for example, the conversion of grassland to cropland which results in high emissions of CO2 and N2O. Most importantly, managed peatland soils are the main source of these emissions, even though their area is small.
In arable farming, the main source of greenhouse gas emissions is nitrogen fertilization and the associated N2O emissions. The task here is to fertilize as efficiently as possible, to avoid nitrogen surpluses, and to optimize the use of farm manure to the extent that as little mineral fertilizer as possible needs to be produced and applied.
The contribution of direct energy use in agriculture to GHG emissions is estimated to be rather small. However, energy savings do not only lead to reductions in GHG emission, but also often to cost savings, making them more attractive to farms than other GHG mitigation options.
To a limited extent, agriculture can also generate renewable energy from residual and waste materials as well as energy crops and consequently save fossil combustibles and associated CO2 emissions. However, energy crop cultivation in particular is not CO2 neutral, and the GHG savings potential can be indirectly diminished or even negated by “exported” land use changes elsewhere.
Driven by efforts to account for the GHG mitigation contribution of biomass for energy use in a comprehensible and consistent manner, there are now several approaches to GHG accounting in the agricultural sector, including single-farm accounting.
Treibhausgasemissionen aus der Landwirtschaft (Landinfo 5/2017)
Die Landwirtschaft steht immer wieder im Fokus, wenn es darum geht, Treibhausgase zu reduzieren. Mal ist der Klimakiller ... weiterlesen