## 3 Results  
### Temporal Variation in pH, Eh, and EC during the Period of the Experiment  
There was a consistent trend showing that pH in the soil solution increased over time during the 15-day incubation experiment. In comparison, the single organic acid treatments (T1-T3) tended to have higher pH compared to the combined organic acid treatments (T4-T7), and the combination of the three organic acid treatment (T7) had the lowest pH on any measurement events among all the 7 treatments (Table 3).  
In contrast, the solution Eh tended to decrease with increasing duration during the incubation experiment. The single organic acid treatments (T1-T3) tended to have lower Eh, as compared to the combined organic acid treatments (T4-T7). The combination of the three organic acid treatment (T7) had the highest Eh on any measurement events among all the 7 treatments (Table 3).  
There were different temporal variation patterns for EC among the 7 treatments in the earlier part (until the 7 th day) of the experiment. Except for T2 and T6 that showed a continuously decreasing trend over time, EC in the treatments fluctuated markedly until the 7 th day and then all the treatments exhibited a consistently decreasing trend toward the end of the experiment with the EC value becoming very low (Table 3).  
\begin{table}
\begin{tabular}{c c c c c} \hline
**Treatments** & **1 d** & **3 d** & **5 d** & **7 d** & **15 d** \\ \hline
**pH** & & & & \\ \hline T1 & 3.63 \(\pm\) 0.03 bE & 4.11 \(\pm\) 0.02 cD & 4.44 \(\pm\) 0.02 cC & 5.38 \(\pm\) 0.10 bB & 6.83 \(\pm\) 0.08 aA \\ T2 & 3.34 \(\pm\) 0.06 cE & 4.78 \(\pm\) 0.01 aD & 5.18 \(\pm\) 0.01 aC & 5.88 \(\pm\) 0.02 aB & 6.70 \(\pm\) 0.10 aA \\ T3 & 3.88 \(\pm\) 0.03 aE & 4.50 \(\pm\) 0.03 bD & 5.04 \(\pm\) 0.04 bC & 6.01 \(\pm\) 0.02 aB & 6.76 \(\pm\) 0.08 aA \\ T4 & 2.86 \(\pm\) 0.02 eE & 3.36 \(\pm\) 0.01 eD & 3.58 \(\pm\) 0.01 eC & 4.29 \(\pm\) 0.02 dB & 5.27 \(\pm\) 0.12 cA \\ T5 & 3.33 \(\pm\) 0.03 cE & 3.77 \(\pm\) 0.02 dD & 4.06 \(\pm\) 0.02 dc & 4.81 \(\pm\) 0.03 cB & 5.66 \(\pm\) 0.06 bA \\ T6 & 2.99 \(\pm\) 0.04 dE & 3.71 \(\pm\) 0.05 dD & 4.07 \(\pm\) 0.04 dC & 4.83 \(\pm\) 0.06 cB & 5.87 \(\pm\) 0.02 bA \\ T7 & 2.73 \(\pm\) 0.01 fE & 3.26 \(\pm\) 0.00 fD & 3.50 \(\pm\) 0.00 fC & 4.22 \(\pm\) 0.04 dB & 4.86 \(\pm\) 0.07 dA \\ \hline
**Eh (mV)** & & & & \\ \hline T1 & 170 \(\pm\) 1.70 eA & 149 \(\pm\) 0.88 dB & 128 \(\pm\) 0.96 dC & 98.1 \(\pm\) 4.57 cD & \(-\)18.8 \(\pm\) 3.33 fE \\ T2 & 186 \(\pm\) 3.06 dA & 112 \(\pm\) 0.81 fB & 86.4 \(\pm\) 0.61 fC & 67.5 \(\pm\) 1.31 dD & \(-\)7.23 \(\pm\) 2.02 eE \\ T3 & 156 \(\pm\) 1.91 fA & 127 \(\pm\) 1.87 eB & 93.9 \(\pm\) 2.29 eC & 59.4 \(\pm\) 1.55 eD & \(-\)19.2 \(\pm\) 1.03 fE \\ T4 & 213 \(\pm\) 1.41 bA & 192 \(\pm\) 0.64 bB & 175 \(\pm\) 0.38 bC & 160 \(\pm\) 1.10 aD & 60.6 \(\pm\) 6.05 bE \\ T5 & 187 \(\pm\) 1.43 dA & 169 \(\pm\) 1.17 cB & 149 \(\pm\) 0.95 cC & 130 \(\pm\) 0.07 bD & 40.1 \(\pm\) 3.07 eE \\ T6 & 205 \(\pm\) 2.41 cA & 172 \(\pm\) 2.69 cB & 147 \(\pm\) 2.37 cC & 128 \(\pm\) 3.31 bD & 29.7 \(\pm\) 1.02 dE \\ T7 & 220 \(\pm\) 0.61 aA & 197 \(\pm\) 0.19 aB & 180 \(\pm\) 0.12 aC & 164 \(\pm\) 2.31 aD & 81.3 \(\pm\) 3.44 aE \\ \hline
**EC (\#S/cm)** & & & & \\ \hline T1 & 1374 \(\pm\) 43.4 cA & 1016 \(\pm\) 2.85 dB & 1385 \(\pm\) 24.0 bA & 874 \(\pm\) 7.00 cC & 25.6 \(\pm\) 0.21 cD \\ T2 & 839 \(\pm\) 17.7 eA & 311 \(\pm\) 2.03 gC & 360 \(\pm\) 4.04 eB & 196 \(\pm\) 3.70 dD & 6.83 \(\pm\) 0.09 eE \\ T3 & 1319 \(\pm\) 15.6 cA & 977 \(\pm\) 7.75 eB & 1390 \(\pm\) 7.88