Climate forcing by crop production is dominated by N2O emissions. “Good agronomic practice” can marginally reduce them, but more targeted approaches are needed.
MAGGE-pH concentrates on the microbial processes responsible for production and consumption of N2O in soils starting with the emerging understanding of how soil pH controls the N2O/(N2O+N2 ) product ratio of denitrification and the N2O yield of nitrification. Since denitrification is the dominant N2O source, emissions from cultivated soils could be reduced by increasing the pH of moderately acidic soils beyond that needed to secure adequate crop growth. MAGGE-pH will deliver the socio-economic analyses to identify the policy instruments needed to secure effective implementation.
The evidence for the pH effect on N2O emissions stems almost exclusively from laboratory experiments. MAGGE-pH will produce stringent testing of different liming strategies under realistic field conditions and generate emission factors for a range of N fertilisers/manure/urine/biochar applications explicit for soil pH.
MAGGE-pH also explores the use of non-calcareous rock powders as a replacement for traditional limes (carbonates), which is highly relevant, because CO2 emissions from carbonates can negate their potential GHG reducing effect; and novel approaches to manage soil pH via fertilisers and manure, in order to reduce both N2O emission and NH3 volatilisation.
Raising soil pH reduces soil nitrous oxide (N2O) emissions during periods in which denitrification prevails. Rapid pH increase due to liming increases N2O emissions from nitrification. Hence, rapid pH increase should be avoided, and suitable soil pH levels maintained by regular maintenance. Model scenarios for German soils based on reported N2O reductions by liming suggest that the N2O saving effect of liming may be offset by CO2 emissions during production and use of agricultural lime if IPCC standard factors for CO2 release from lime are used. However, IPCC (Intergovernmental Panel on Climate Change) emission factors for lime are likely wrong for moderately acidic soils and should be revised. More data are needed to evaluate the overall GHG effect of liming on a per-tonne-of-product basis.
*At the time of the proposal. Please consider this data as an accurate estimate; it may vary during the project’s lifespan.
Total costs include in kind contribution by grant holders and can therefore be higher than the total requested funding.