## 3 Results
### Temporal Variation in Solution-borne Al, Fe, and Mn During the Period of the Experiment
\begin{table}
\begin{tabular}{c c c c c} \hline
**Treatment** & **1 d** & **3 d** & **5 d** & **7 d** & **15 d** \\ \hline
**Al** & & & & \\ \hline T1 & 347 \(\pm\) 14.8 cD & 533 \(\pm\) 7.06 eC & 648 \(\pm\) 6.64 dB & 744 \(\pm\) 19.6 dB & 1632 \(\pm\) 27.7 aA \\ T2 & 368 \(\pm\) 7.52 cC & 348 \(\pm\) 4.69 fD & 273 \(\pm\) 7.55 fE & 1279 \(\pm\) 14.3 bA & 1144 \(\pm\) 10.5 cAB \\ T3 & 156 \(\pm\) 9.59 dE & 261 \(\pm\) 6.04 gD & 322 \(\pm\) 21.16 eC & 794 \(\pm\) 2.99 dB & 1436 \(\pm\) 3.93 bA \\ T4 & 634 \(\pm\) 25.9 aC & 929 \(\pm\) 11.3 bAB & 1048 \(\pm\) 12.2 bA & 1157 \(\pm\) 20.8 cA & 631 \(\pm\) 20.4 fC \\ T5 & 494 \(\pm\) 14.1 bC & 751 \(\pm\) 8.26 cB & 885 \(\pm\) 5.99 cA & 337 \(\pm\) 4.10 cD & 688 \(\pm\) 13.0 eB \\ T6 & 480 \(\pm\) 21.7 bC & 624 \(\pm\) 16.7 dB & 662 \(\pm\) 22.3 dB & 1135 \(\pm\) 21.0 cA & 312 \(\pm\) 8.78 gD \\ T7 & 674 \(\pm\) 3.10 aE & 1055 \(\pm\) 15.9 aC & 1237 \(\pm\) 10.5 aB & 1603 \(\pm\) 20.4 aA & 791 \(\pm\) 23.7 dD \\ \hline
**Fe** & & & & & \\ \hline T1 & 287 \(\pm\) 10.9 eE & 527 \(\pm\) 3.63 dD & 714 \(\pm\) 10.9 dC & 1066 \(\pm\) 28.2 dB & 2583 \(\pm\) 40.9 aA \\ T2 & 339 \(\pm\) 4.11 dC & 190 \(\pm\) 7.80 eD & 94.4 \(\pm\) 3.18 gE & 1487 \(\pm\) 11.5 cB & 2340 \(\pm\) 33.2 bA \\ T3 & 105 \(\pm\) 6.19 fE & 208 \(\pm\) 5.20 eD & 328 \(\pm\) 31.2 fC & 682 \(\pm\) 5.85 eB & 1674 \(\pm\) 23.3 cA \\ T4 & 639 \(\pm\) 22.3 bD & 982 \(\pm\) 23.2 bC & 1132 \(\pm\) 14.7 bB & 1556 \(\pm\) 17.0 bA & 1170 \(\pm\) 17.3 dB \\ T5 & 406 \(\pm\) 5.77 cD & 757 \(\pm\) 54.9 cB & 883 \(\pm\) 8.77 cA & 364 \(\pm\) 38.6 fD & 589 \(\pm\) 19.5 eC \\ T6 & 414 \(\pm\) 9.97 cB & 522 \(\pm\) 17.4 dA & 568 \(\pm\) 18.2 eA & 400 \(\pm\) 0.03 fBC & 381 \(\pm\) 16.7 fC \\ T7 & 707 \(\pm\) 15.9 aD & 1100 \(\pm\) 2.77 aC & 1346 \(\pm\) 6.66 aB & 1967 \(\pm\) 18.2 aA & 1142 \(\pm\) 6.54 dC \\ \hline
**Mn** & & & & \\ \hline T1 & 183 \(\pm\) 10.9 eD & 323 \(\pm\) 7.24 dC & 416 \(\pm\) 7.44 dB & 472 \(\pm\) 30.1 cB & 1054 \(\pm\) 11.9 aA \\ T2 & 158 \(\pm\) 0.20 eC & 125 \(\pm\) 1.70 fCD & 83.7 \(\pm\) 2.95 gE & 616 \(\pm\) 42.4 bB & 885 \(\pm\) 5.87 bA \\ T3 & 80.6 \(\pm\) 3.35 fE & 144 \(\pm\) 3.22 eD & 225 \(\pm\) 2.60 fC & 491 \(\pm\) 32.1 cB & 746 \(\pm\) 16.6 cA \\ T4 & 325 \(\pm\) 13.2 bD & 507 \(\pm\) 8.45 bBC & 543 \(\pm\) 4.66 cB & 700 \(\pm\) 19.9 bA & 73.8 \(\pm\) 4.84 fE \\ T5 & 288 \(\pm\) 9.84 cD & 501 \(\pm\) 4.04 bB & 563\(\pm\) 4.01 bA & 341 \(\pm\) 39.9 dCD & 372 \(\pm\) 9.07 eC \\ T6 & 244 \(\pm\) 9.73 dC & 354 \(\pm\) 6.28 cB & 359 \(\pm\) 6.76 eB & 96.8 \(\pm\) 6.86 eD & 369 \(\pm\) 7.05 eA \\ T7 & 370\(\pm\)1.02 aD & 641 \(\pm\) 6.14 aC & 702 \(\pm\) 6.34 aB & 954 \(\pm\) 6.81 aA & 688 \(\pm\) 3.24 dB \\ \hline \end{tabular}  
All values are presented as mean \(\pm\) standard error (\(n=3\)). Means with different lower-case letters in the same column for each parameter are significantly different at \(p<0.05\). Means with different capital letters in the same row are significantly different at \(p<0.05\).  
\end{table} 
Table 4: Variation in Al, Fe, and Mn (mg/L) in the extracting solutions during the period of experiment. The temporal variation pattern in solution-borne Fe in T4-T6 was also very similar to that in solution-borne Al in T4 and T6, respectively. However, there was no marked variation in solution-borne Fe for T5, which is different from the solution-borne Al in T5 that had a strong peak on the 7 th day of the experiment (Table 4). There was a high level of similarity in solution-borne Fe and solution-borne Al for T7 (Table 4). In general, the temporal variation in solution-borne Mn showed a similar pattern to that of solution-borne Al for T1-T3 (Table 4). However, for the combined two acid treatments (T4-T6), the temporal variation in solution-borne Mn was more similar to that of solution-borne Fe but the peaks on the 5 th day were much more evident, as compared to the latter (Table 4). For T7, the temporal variation pattern in solution-borne Mn was highly consistent with that for either Al or Fe (Table 4).