system in the “La Cage” long-term trial at the INRA research centre
of Versailles (France) and stored at 4 C until use. The plots sampled
were set to wheat at the time of sampling. Organic carbon and total
nitrogen contents at a depth of 6e10 cm (the depth from which
the samples were taken for the incubation) were 9.3 0.7 and
1.0 0.07 mg g1 dried soil, respectively. The soil is classified as
Eutric Cambisol (FAO; 17% clay, 56% silt and 27% sand) with a pH
(water: soil ¼ 1) of 7.4 and a CEC of 11.5 cmol kg1.