Effects of mire disturbance by Sika deer on nitrogen fixation and denitrification in Ozegahara Mire, Japan

Figures & data

Figure 1. (a) Soil moisture (%), (b) pH (left) and EC (right; mS m⁻¹) and (c) mineral N (upper: nitrate, lower: ammonium, mg N kg⁻¹ wet soil) contents in disturbed (D) and undisturbed (UD) sites.

Figure 2. ARA of disturbed (D) and undisturbed (UD) soils under aerobic (upper) or anaerobic (lower) conditions with different temperatures.

Figure 3. Correlation between ARA and ammonium N of disturbed (D) and undisturbed (UD) soils with different temperatures.

Figure 4. Denitrification activities of disturbed (D) and undisturbed (UD) soils under aerobic (upper) or anaerobic (lower) conditions with different temperatures.

Figure 5. Stable isotope ratios of disturbed (D) and undisturbed (UD) soils.

Table 1. Q₁₀ (25/15°C) of ARA and denitrification activities of disturbed (D) and undisturbed (UD) soils under aerobic or anaerobic conditions

		ARA	Denitrification
		Anaerobic	Aerobic	Anaerobic	Aerobic
Site A	D1	1.68	-*	3.83	1.83
	D2	0.69	-	2.37	2.84
	UD1	3.93	10.05	3.01	1.72
Site B	D3	0.27	2.55	2.08	1.83
	UD2	4.01	-	2.54	1.82
	UD3	1.69	-	2.03	1.70

*ARA was below detection limit.

Table 2. Multi-regression analysis of affecting factors for anaerobic ARA in disturbed (D) and undisturbed (UD) soils

	Standardized partial regression coefficient				Determination coefficient
	Temperature	NH4^+-N	NO3^–N	Disturbance	R^2	p value
	(F1)	(F2)	(F3)	(F4)
Site (Formula^#)	α1	α2	α3	α4
D + UD (1)	0.248*	-0.298*	0.111^NS	0.502***	0.489	<0.01
D (2)	-0.227^NS	-0.176^NS	0.084^NS	-	-0.027	0.52
UD (2)	0.557^NS	-0.568**	-0.31^’	-	0.571	<0.01

^#Formula, see text, ***indicates p < 0.001, **p < 0.01, *p < 0.05, and ‘p < 0.1, respectively.