# Table 4 Relationship of the soil respiration and the heterotrophic respiration with 5-cm soil temperature or moisture content under different simulated acid rain treatments

Treatment 5-cm soil temperature 5-cm soil water content 5-cm soil temperature and water content
Fitting equation (y = a × eb × T) Q10 Fitting equation (y = cM2 + dM + e) Fitting equation (y = f × eg × T × Mh)
a b R 2 a b c R 2 a b c R 2
UTCK 0.69 0.06 0.95** 1.90 0.03 −1.59 21.02 0.11 1.96 0.06 −0.33 0.96**
UT4.0 0.62 0.07 0.94** 1.99 0.03 −1.53 20.51 0.09 2.30 0.07 −0.41 0.96**
UT3.25 0.51 0.07 0.94** 2.10 0.03 −1.66 21.81 0.11 1.46 0.07 −0.33 0.95**
UT2.5 0.42 0.08 0.91** 2.27 0.04 −1.82 23.69 0.11 1.58 0.08 −0.41 0.92**
TCK 0.47 0.07 0.86** 1.93 0.10 −4.57 54.75 0.23 1.27 0.07 −0.31 0.87**
T4.0 0.37 0.08 0.94** 2.16 0.11 −5.34 63.40 0.28* 0.60 0.08 −0.15 0.94**
T3.25 0.38 0.07 0.92** 1.97 0.09 −4.17 50.03 0.28* 1.98 0.07 −0.52 0.93**
T2.5 0.28 0.08 0.83** 2.25 0.10 −4.54 54.03 0.29* 0.55 0.08 −0.21 0.83**
1. In the equations, y represents the soil respiration rate (μmol∙m−2·s−1), T represents 5-cm soil temperature (°C), M represents 5-cm soil moisture content, and a, b, c, d, e, f, g, and h are constants. UTCK, UT4.0, UT3.25, and UT2.5 indicate control, pH 4.0, pH 3.25, and pH 2.5 simulated acid rain in the untrenched plots, respectively; TCK, T4.0, T3.25, and T2.5 indicate the control, pH 4.0, pH 3.25, and pH 2.5 simulated acid rain in the trenched plots, respectively. * significant correlation (P < 0.05); ** highly significant correlation (P < 0.01)