Soil Liming as a means of reducing N2O emissions - disentangling the effect of pH

Nitrogen fertilization of agricultural soils contribute nearly a quarter of total global emissions of nitrous oxide (N2O), a powerful ozone depleting and greenhouse gas. Increasing soil pH by addition of lime has been proposed as a solution for reducing N2O emissions.

However, the results of field experiments have been inconsistent, and the mechanisms by which soil pH determines N2O emissions remains unclear.

This project examines how the interaction between soil pH and the microbial communities that drive the nitrogen cycle determine the rate of N2O production and consumption in arable soils.

The specific aims are i) identify genera and context-specific effects of long-term manipulation of soil pH on potential N2O emission from Swedish arable soils ii) determine direct and indirect effects of changes in soil pH onthe structure and functioning of microbial communities that produce and consume N2O in soils, and iii) establish and validate models that predict the capacity of a soil microbiome to act as a potential source or sink of N2O in response to liming.

These results will be used as a basis for Best Management Practices (BMPs) on the use of soil liming in reducing N2O emissions from the agricultural sector, and extension to end users will be established through a combination of popular science articles in trade journals and presentation of BMPs at local and national agricultural meetings.