Table 2.

Modelled double first-order kinetic parameters describing the mineralisation of ¹⁴C-labelled trialanine in Arctic and temperate soils subjected to 1 or 3 successive freeze–thaw (FT) cycles (−7.5 to +5 °C) and their respective non-frozen controls

Trialanine
Soil	Parameter	Control	FT	3 Control	3FT
Meadow mineral	a 1 (%)	34.6 ± 3.7	37.8 ± 1.4	38.8 ± 3.4	39.9 ± 0.9
	k 1 (h−1)	0.31 ± 0.05	0.24 ± 0.08	0.16 ± 0.03	0.13 ± 0.03
	a 2 (%)	63.5 ± 4.0	60.1 ± 1.4	59.3 ± 3.7	58.2 ± 0.9
	k 2 (× 10−3 h−1)	0.88 ± 0.06	1.02 ± 0.19	1.03 ± 0.07	0.98 ± 0.14
Meadow organic	a 1 (%)	39.4 ± 1.2	41.8 ± 1.5	43.2 ± 1.5	38.8 ± 4.3
	k 1 (h−1)	0.54 ± 0.04!	0.47 ± 0.03	0.24 ± 0.02!	0.34 ± 0.07
	a 2 (%)	59.3 ± 1.1	57.0 ± 1.4	54.9 ± 2.7	59.7 ± 4.5
	k 2 (×10−3 h−1)	0.81 ± 0.26	0.68 ± 0.05	0.78 ± 0.12	0.66 ± 0.05
Heath mineral	a 1 (%)	31.4 ± 7.4	29.6 ± 10.1	34.2 ± 5.8	34.1 ± 3.9
	k 1 (h−1)	0.12 ± 0.01	0.22 ± 0.15	0.08 ± 0.01	0.06 ± 0.01
	a 2 (%)	68.1 ± 7.7	69.6 ± 10.4	65.1 ± 5.9	65.3 ± 4.0
	k 2 (×10−3 h−1)	1.37 ± 0.09	1.00 ± 0.29	1.33 ± 0.11	1.34 ± 0.16
Temperate	a 1 (%)	47.43 ± 1.2*	55.43 ± 0.7*	48.87 ± 1.2	53.16 ± 0.7
	k 1 (h−1)	1.1 ± 0.03*	0.9 ± 0.03*	1.1 ± 0.06	0.8 ± 0.02
	a 2 (%)	52.01 ± 1.2*!	43.73 ± 0.7*	50.73 ± 1.1!	46.17 ± 0.8
	k 2 (×10−3 h−1)	0.8 ± 0.04	0.9 ± 0.05	0.8 ± 0.01	1.0 ± 0.05

* A statistical difference between freeze–thaw treatment and the control

^! Statistical difference over time (i.e. between the first and third control or 1FT and 3FT), (p < 0.05). Values represent mean ± SE (n = 4)