Management of agricultural ecosystems and carbon storage balance

The warming up of the atmosphere is a recognised phenomenon. Since September 2002, already 84 countries signed the Kyoto protocol but only when enough countries, covering at least 55% of all CO2 equivalent emissions, have signed, this protocol can be implemented. It means that world wide the CO2 equivalent emissions have to be reduced with on average 5% in the period 2008-2012. For the EU countries this will be an 8% reduction in comparison to the reference year 1990. The general world policy and especially the EU policy for the development and support of agriculture was not in favour of the C storage capacity and had a very negative effect on the total CO2 equivalent emission. It is not clear what is meant in the Kyoto protocol with the net changes in greenhouse gas emissions from sources and removals by sinks resulting from direct human-induced land use change and direct human induced activities since 1990. Which activities in agriculture will be accepted for the calculation of the C storage balance? In general crop land and arable fields are carbon sources, whereas the majority of grassland are carbon sinks. It is therefor clear that all efforts should be focused on an increase of permanent grassland area. The possibilities of human activities like reduced or no tillage, incorporation of crops rests and farmyard manure, cover cropping after harvest of the main crop and managing verges, to increase the C storage in agriculture are discussed, but it is not for sure that finally their capacities will be accepted. The result of the mentioned activities are highly sensitive to pedo-climatic and local agricultural conditions, and thus markedly contrasted as a function of regions. Only by taking in account all processes influencing CO2 storage and CO2, N2O and CH4 emissions may lead to the calculation of the final C sequestration balance, to be attributed to one or another agricultural activity.