Table 1. Characterization of the three soil variants selected for this study from the ‘static fertilization experiment' in Bad Lauchstädt, Germany.

Long-term fertilization regime*	Soil variant
	NIL	NPK	FYM
	No fertilizer	Mineral fertilizer	Mineral fertilizer plus farmyard manure
Soil organic carbon (g kg−1)	17.7a	21.1b	25.9c
Soil microbial biomass (mg kg−1)**	129a	164b	264c
pH value	7.4a	6.4b	6.5b
Soil particle size fractions (%)***
Sand and POM (63–2000 μm)	5.8	6.3	7.8
Coarse silt (20–63 μm)	40.1	39.6	39.0
Fine silt (2–20 μm)	31.1	34.1	30.1
Clay (<2 μm)	23.2	20.4	23.2

Abbreviation: POM, particulate organic matter.

Values followed by different alphabets indicate differences between soil variants.

^*Fertilizations were conducted on an annual basis according to good agricultural practice since 1902; farmyard manure was only applied every second year—sampling was conducted in October 2008, 24 months after the last application of farmyard manure.

^**Determined by chloroform–fumigation incubation, according to Jenkinson and Powlson (1976).

^***Achieved using the ultrasonication wet-sieving centrifugation method according to Amelung et al. (1998), modified by Neumann et al. (2013).