Variation of Q₁₀ values in a fenced and a grazed grassland on the loess plateau, northwestern China

Figures & data

Table 1 Regression equation of soil and microbial respiration and soil temperature (2008–2010).

	SR	R^2	MR	R^2
Fenced grassland	SR = 0.49e^0.0558T	0.94	MR = 0.34e^0.0505T	0.89
Grazed grassland	SR = 0.36e^0.0519T	0.82	MR = 0.22e^0.0438T	0.91

Note: SR, soil respiration; MR, microbial respiration; T, soil temperature at 2 cm.

Figure 1 Seasonal variations in soil temperature (a: 2 cm), soil volumetric moisture (b: 0–10 cm) and soil and microbial respiration (c) measured in fenced (G–, 2008–2010) and grazed grassland (G+, 2009–2010). The bars in (b) represent precipitation. CO₂: carbon dioxide.

Figure 2 The relationship between soil respiration (SR) and microbial respiration (MR), and (a) soil temperature, and (b) soil moisture during the entire experiment. The open and black triangles indicate the data of SR and MR in the grazed grassland (G+); and open and black circles are data of SR and MR in the fenced grassland (G–). The solid line indicates the relationship between SR and soil temperature in G–; the medium dashed line shows the relationship between MR and soil temperature in G–; the long dashed line shows the relationship between SR and soil temperature in G+; and the short dashed line shows the relationship between MR and soil temperature in G+. CO₂: carbon dioxide.

Figure 3 Seasonal variations of short-term Q₁₀ (temperature sensitivity) values of soil respiration (SR) and microbial respiration (MR) in the fenced grassland (G–, 2008–2010) and grazed grassland (G+, 2009–2010).

Figure 4 Relationships between short-term Q₁₀ values and soil temperature (at 2 cm depth). (a) Q₁₀ of microbial respiration (MR) in the fenced grassland (G–); (b) Q₁₀ of soil respiration (SR) in G–; (c) Q₁₀ of MR in the grazed grassland (G+); (d) Q10 of SR in G+.

Figure 5 Relationships between short-term Q₁₀ values and soil moisture (0–10 cm). Black circles: Q₁₀ of microbial respiration (MR) in the fenced grassland (G–); open circles: Q₁₀ of soil respiration (SR) in the fenced grassland (G–); black triangles: Q₁₀ of microbial respiration in the grazed grassland (G+); open triangles: Q₁₀ of soil respiration in the grazed grassland (G+).

Table 2 Long-term apparent Q₁₀ (temperature sensitivity) values and means of soil and microbial respiration, root biomass and soil organic carbon in the fenced and grazed grassland during the entire experimental period.

	SR (μmol CO2 m^−2 s^−1)	Q10 of SR	MR (μmol CO2 m^−2 s^−1)	Q10 of MR	Root biomass (g m^−2)	SOC (g kg^−1)
Fenced grassland	1.47 ± 0.16 a	1.75	1.06 ± 0.09 a	1.66	327.21 ± 20.28 a	8.71 ± 0.18 a
Grazed grassland	0.93 ± 0.06 b	1.68	0.66 ± 0.07 b	1.55	271.94 ± 6.21 b	7.67 ± 0.21 b

Note: CO₂, carbon dioxide; SR, soil respiration; MR, microbial respiration; SOC, soil organic carbon. Different letters in the same column indicate a signficant difference between fenced and grazed grassland.