The inhibiting effect of nitrate fertilisation on methane uptake of a temperate forest soil is influenced by labile carbon

Abstract

Upland soils are the most important terrestrial sink for the greenhouse gas CH 4. The oxidation of CH 4 is highly influenced by reactive N which is increasingly addede soils. The interacting effects of soil N availability and the labile C pool on CH 4 oxidation are not well understood. We conducted a laboratory experiment with soil columns consisting of homogenised topsoil material from a temperate broad-leaved forest to study the net CH 4 flux under the combined or isolated addition of NO 3- and glucose as a labile C source. Addition of NO 3- and glucose reduced the net CH 4 uptake of the soil by 86% and 83%, respectively. The combined addition of both agents led to a nearly complete inhibition of CH 4 uptake (reduction by 99.4%). Our study demonstrates a close link between the availability of C and N and the rate of CH 4 oxidation in temperate forest soils. Continued deposition of NO 3- has the potential to reduce the sink strength of temperate forest soils for CH 4. © 2012 Springer-Verlag.