Table 2. Gross N transformation rates in forest soils (0–20 cm) estimated using a ¹⁵N tracing model.

Region	No1)	M2)	INH4	TNi	ONH4	INO3	DNRA	NC	NR
Northern	1	2.16 ± 0.15	0.31 ± 0.14	0.22 ± 0.02	0.22 ± 0.04	0	0.11 ± 0.03	0.10 ± 0.05	0.50 ± 0.09
	2	2.14 ± 0.09	0.26 ± 0.08	0.07 ± 0.01	0.07 ± 0.01	0	0.04 ± 0.02	0.03 ± 0.01	0.57 ± 0.18
	3	1.02 ± 0.06	0	0.14 ± 0.00	0.13 ± 0.00	0	0.08 ± 0.01	0.13 ± 0.00	0.57 ± 0.04
	4	2.29 ± 0.17	0	0.88 ± 0.05	0.19 ± 0.02	0	0.02 ± 0.01	0.08 ± 0.01	0.02 ± 0.01
	5	2.21 ± 0.12	1.53 ± 0.53	0.85 ± 0.05	0.39 ± 0.00	0	0.01 ± 0.00	0.18 ± 0.01	0.01 ± 0.00
	6	1.62 ± 0.11	0.01 ± 0.01	1.41 ± 0.16	0.80 ± 0.03	0.31 ± 0.27	0.03 ± 0.02	0.50 ± 0.02	0.24 ± 0.11
	7	1.87 ± 0.23	2.58 ± 0.38	4.53 ± 0.03	4.53 ± 0.05	0	0.07 ± 0.04	2.43 ± 0.16	0.02 ± 0.01
	8	1.12 ± 0.05	0.01 ± 0.00	2.46 ± 0.12	2.24 ± 0.07	0	0.01 ± 0.01	2.00 ± 0.15	0
Southern	9	3.95 ± 0.11	1.94 ± 0.06	0.49 ± 0.15	0.02 ± 0.01	0.55 ± 0.16	0.01 ± 0.01	0.004 ± 0.00	1.14 ± 0.40
	10	1.52 ± 0.12	0.22 ± 0.12	0.81 ± 0.04	0.05 ± 0.03	0.69 ± 0.05	0.02 ± 0.01	0.03 ± 0.02	0.88 ± 0.06
	11	1.93 ± 0.15	0.35 ± 0.22	0.91 ± 0.15	0.05 ± 0.01	0.76 ± 0.02	0.02 ± 0.01	0.03 ± 0.03	0.86 ± 0.14
	12	3.70 ± 0.12	0.94 ± 0.12	0.06 ± 0.00	0.05 ± 0.01	0.11 ± 0.03	0.02 ± 0.00	0.01 ± 0.01	2.17 ± 0.31
	13	4.63 ± 0.19	2.34 ± 0.50	0.49 ± 0.02	0.23 ± 0.02	0.30 ± 0.03	0.04 ± 0.00	0.05 ± 0.01	0.69 ± 0.05
	14	2.72 ± 0.08	2.25 ± 0.53	0.93 ± 0.07	0.50 ± 0.01	0.70 ± 0.03	0.05 ± 0.01	0.18 ± 0.04	0.81 ± 0.06
	15	3.52 ± 0.18	2.25 ± 0.19	0.93 ± 0.02	0.51 ± 0.03	0.69 ± 0.03	0.05 ± 0.00	0.14 ± 0.02	0.80 ± 0.03
	16	2.29 ± 0.16	0.06 ± 0.02	1.00 ± 0.04	0.19 ± 0.04	0.74 ± 0.04	0.17 ± 0.01	0.09 ± 0.06	0.91 ± 0.04
	17	9.20 ± 0.43	4.99 ± 1.40	0.66 ± 0.05	0.65 ± 0.08	0.11 ± 0.06	0.35 ± 0.04	0.07 ± 0.02	0.70 ± 0.08
	18	5.79 ± 0.65	6.17 ± 1.05	0.52 ± 0.04	0.37 ± 0.02	0.25 ± 0.12	0.29 ± 0.02	0.06 ± 0.00	1.04 ± 0.15
	19	3.37 ± 0.35	0	1.14 ± 0.08	0.12 ± 0.02	0.59 ± 0.16	0.05 ± 0.01	0.04 ± 0.01	0.56 ± 0.09
	20	2.41 ± 0.36	2.33 ± 0.49	0.90 ± 0.06	0.13 ± 0.01	0.65 ± 0.13	0.06 ± 0.01	0.05 ± 0.01	1.63 ± 0.16
	21	3.54 ± 0.22	3.74 ± 0.47	0.72 ± 0.04	0	0.22 ± 0.01	0.07 ± 0.01	0	1.56 ± 0.02
	22	3.46 ± 0.21	2.88 ± 0.26	1.97 ± 0.04	0.04 ± 0.00	1.71 ± 0.09	0.07 ± 0.01	0.01 ± 0.00	0.90 ± 0.05
	23	3.01 ± 0.37	2.69 ± 0.27	0.76 ± 0.10	0.07 ± 0.01	0.91 ± 0.18	0.06 ± 0.01	0.02 ± 0.00	1.27 ± 0.29
	24	2.25 ± 0.16	0.30 ± 0.13	0.81 ± 0.10	0.12 ± 0.01	0.42 ± 0.18	0.04 ± 0.01	0.05 ± 0.01	1.93 ± 0.23
	25	3.33 ± 0.17	1.62 ± 0.38	0.52 ± 0.03	0.47 ± 0.02	0.75 ± 0.07	0	0.14 ± 0.01	1.44 ± 0.11
Northern soils3)		1.80a	0.59a	1.32a	1.07b	0.04a	0.05a	0.68b	0.24a
Southern soils (lab incubation)		3.04b	1.80a	0.78a	0.14a	0.65b	0.04a	0.05a	1.27b
Southern soils (field incubation)4)		4.83b	2.69ab	0.85a	0.37a	0.48b	0.18b	0.08a	0.80b

¹⁾No., site number according to soil site listed from north to south.

²⁾M, mineralization rate of organic N pool; I_NH4, total immobilization of NH₄⁺; TNi, total nitrification rate (autotrophic nitrification + heterotrophic nitrification); O_NH4, autotrophic nitrification; I_NO3, immobilization of NO₃⁻; DNRA, dissimilatory NO₃⁻ reduction to NH₄⁺; NC, nitrification capacity; NR, NO₃⁻ retention capacity.

3)Identical letters indicate no significant differences in the average values between groups.

4)Gross N transformation rates in soils 15–19 were determined by field incubation.