Table 1. Properties of soils used in experiments.

No.	Reference Soil Group (acc. to WRB)	Use	Corg g kg−1	CHA g kg−1	CFA g kg -1	CHA/CFA	CHS g kg−1	Texture class (WRB)	DNA concentration (ng/µl)	A260/A280*	A260/A230*
1	Fluvisol	Meadow	26.2	10.3	1.42	7.25	11.72	Loamy sand	25.5	1.93	1.19
2	Regosol	Plough field	11.2	2.8	0.91	3.08	3.71	Sandy loam	61.3	1.92	1.20
3	Cambisol	Meadow	10.9	9.67	1.30	7.45	10.99	Loamy sand	11.7	1.98 (2.46)	0.44 (1.20)
4	Cambisol	Plough field	7.7	5.99	1.02	5.87	7.01	Sandy loam	216.5	1.82	0.68
5	Cambisol	Forest	20.1	14.97	1.92	7.8	16.89	Sandy loam	46.8	1.91 (2.07)	1.13 (1.4)
6	Arenosol	Forest	29.2	27.32	2.49	10.97	29.81	Sandy loam	32.5	1.89 (1.95)	1.31 (1.90)
7	Histosol	Meadow	40.3	34.66	2.70	12.84	37.36	Silt loam	200.8	1.92 (1.95)	1.49 (1.53)
8	Luvisol	Plough field	9.3	3.36	0.91	3.69	4.27	Silt loam	30.1	1.85	1.20

Notes:

C_org, organic carbon content; C_HA, humic acids carbon content; C_FA, fulvic acids carbon content; C_HA/C_FA, ratio of humic/fulvic acids carbon content; C_HS, humic substances carbon content.

^*Purity of DNA extracted from tested samples expressed as the ratio of absorbance A₂₆₀/A₂₈₀ and A₂₆₀/A₂₃₀ (values after additional purification of bold samples are presented in brackets) (Tables S1 and S2).