Mitigating Agricultural Greenhouse Gas Emissions by improved pH management of soils; MAGGE-pH

Direct nitrous oxide emissions might be mitigated by an optimized pH management in agricultural soils. The project MAGGE pH investigated potentials and trade-offs of a greenhouse gas optimized pH regulation at agricultural soils by lab experiments and modelling. • Liming effects and pH effects on fluxes of CO2, N2O and N2 from agricultural soils were investigated by lab incubations and lysimeter experiments. Results indicate that soil-pH controls the N2O/(N2O+N2) product ratio. Thus, soils with elevated pH emitted less nitrous oxide emissions. • The analyses of a meta data set showed also less nitrous oxide emissions for field sites with higher soil pH supporting the findings of the lab experiments. • In Germany, about 41% of arable land and 52% of grasslands are characterized by soil pH below recommended intervals. Thus, there is potential to reduce nitrous oxide emissions by just implementing recommended liming practise. • On the other side, CO2 emissions due to liming with carbonates which are estimated with emission factor approaches counteract reduced nitrous oxide emissions partly.