Net primary productivity and soil carbon balance of different brage production systems

摘要

Carbon sequestration has the potential to reduce greenhouse gas (GHG) emissions of forage production, data on intersystem comparability is scarce. Hence, in a field experiment in northern Germany, the iboveground (ANPP) and belowground (BNPP) net primary productivity of three forage production systems (a crop rotation (grass-clover, maize and winter wheat); continuous maize; and grassland) with and without fertilisation were quantified and a carbon budget was created. While the net primary production(NPP) was similar across all systems, the belowground fraction of the NPP (fBNPP) was higher in grasslands with up to 35%, compared to 18 and 23% in continuous maize and the crop rotation. Aboveground biomass was comparable across years, yet in 2013/2014 the grassland and crop rotation lenefitted from the mild winter, resulting in additional C input. Moreover, the crop rotation provided higher harvestable yields compared to grassland and similar figures compared to continuous maize, with Ian almost neutral carbon balance, whereas the continuous maize resulted in simulated decrements in soil carbon stocks of up to 18 t C ha~(-1) in the long-term (~100 years).