## 3 Results and Discussion
### Effect of Treated Sludge on Soil Fertility, and Chemical and Microbiological Properties
\begin{table}
\begin{tabular}{l c c c c c c} \hline \hline
**Treatment** & **NH\({}_{4}\)-N** & **NO\({}_{3}\)-N** & **Olsen-P** & **K** & **Ca** & **Mg** \\ \hline \multicolumn{8}{c}{**mg kg\({}^{-1}\)**} \\ \hline \multicolumn{8}{c}{**Acid Soil**} \\ \hline AcB & 74.0 \(\pm\) 1.4 a & 30.4 \(\pm\) 1.7 d & 35.8 \(\pm\) 2.4 d & 110.7 \(\pm\) 6.0 cd & 858 \(\pm\) 58 bc & 167 \(\pm\) 19 b \\ AcV & 61.5 \(\pm\) 0.7 c & 34.8 \(\pm\) 1.0 c & 32.3 \(\pm\) 0.3 d & 100.7 \(\pm\) 1.2 e & 690 \(\pm\) 33 cd & 235 \(\pm\) 15 a \\ AcBc & 48.7 \(\pm\) 1.5 d & 22.0 \(\pm\) 2.1 e & 35.4 \(\pm\) 5.2 d & 114.0 \(\pm\) 2.0 c & 809 \(\pm\) 99 c & 135 \(\pm\) 10 c \\ AcL & 65.8 \(\pm\) 1.0 b & 55.0 \(\pm\) 2.8 b & 60.5 \(\pm\) 3.8 a & 87.3 \(\pm\) 2.9 g & 3672 \(\pm\) 150 a & 79 \(\pm\) 2 d \\ AcD & 74.2 \(\pm\) 6.2 a & 32.4 \(\pm\) 1.7 cd & 44.2 \(\pm\) 3.6 c & 107.3 \(\pm\) 0.6 d & 1002 \(\pm\) 33 b & 164 \(\pm\) 12 b \\ AcIFX & 72.0 \(\pm\) 0.4 a & 68.1 \(\pm\) 1.5 a & 48.5 \(\pm\) 2.0 bc & 144.7 \(\pm\) 1.2 a & 417 \(\pm\) 70 e & 78 \(\pm\) 4 d \\ AcIFX & 29.2 \(\pm\) 1.2 e & 10.0 \(\pm\) 0.3 f & 52.4 \(\pm\) 2.5 b & 132.0 \(\pm\) 1.7 b & 554 \(\pm\) 123 de & 90 \(\pm\) 12 d \\ AcC & 26.8 \(\pm\) 0.9 e & 8.9 \(\pm\) 0.6 f & 20.2 \(\pm\) 1.8 e & 93.0 \(\pm\) 2.6 f & 432 \(\pm\) 73 e & 84 \(\pm\) 10 d \\ \hline \(p\) F-test & \textless{}0.001 & \textless{}0.001 & \textless{}0.001 & \textless{}0.001 & \textless{}0.001 & \textless{}0.001 \\ \hline \multicolumn{8}{c}{**Alkaline Soil**} \\ \hline AIB & 26.4 \(\pm\) 5.4 b & 108.3 \(\pm\) 6.2 c & 31.1 \(\pm\) 3.1 bc & 145.7 \(\pm\) 9.0 b & 4399 \(\pm\) 38 b & 671 \(\pm\) 12 b \\ AIV & 25.2 \(\pm\) 0.9 b & 114.7 \(\pm\) 1.2 bc & 29.0 \(\pm\) 2.2 cd & 141.3 \(\pm\) 1.5 b & 4146 \(\pm\) 130 c & 703 \(\pm\) 9 a \\ AIBc & 18.1 \(\pm\) 1.2 d & 92.5 \(\pm\) 8.3 d & 23.7 \(\pm\) 9.1 de & 141.0 \(\pm\) 5.3 b & 4070 \(\pm\) 89 c & 643 \(\pm\) 7 c \\ AIL & 50.6 \(\pm\) 4.6 a & 85.9 \(\pm\) 6.3 d & 36.7 \(\pm\) 0.8 b & 136.7 \(\pm\) 3.2 b & 4740 \(\pm\) 146 a & 567 \(\pm\) 26 d \\ AID & 23.2 \(\pm\) 3.0 b & 126.4 \(\pm\) 21 a & 33.2 \(\pm\) 3.4 bc & 134.7 \(\pm\) 1.5 b & 4069 \(\pm\) 94 c & 664 \(\pm\) 10 bc \\ AIFX & 47.6 \(\pm\) 0.4 a & 118.1 \(\pm\) 0.8 b & 50.0 \(\pm\) 3.1 a & 173.3 \(\pm\) 6.5 a & 3980 \(\pm\) 105 c & 637 \(\pm\) 14 c \\ AIFX & 18.6 \(\pm\) 0.3 d & 54.5 \(\pm\) 1.7 f & 51.2 \(\pm\) 3.8 a & 168.3 \(\pm\) 8.5 a & 3778 \(\pm\) 156 d & 642 \(\pm\) 12 c \\ AIC & 17.6 \(\pm\) 0.3 d & 64.7 \(\pm\) 3.6 e & 18.3 \(\pm\) 1.7 e & 117.7 \(\pm\) 17.2 c & 4023 \(\pm\) 11 c & 656 \(\pm\) 26 bc \\ \hline \(p\) F-test & \textless{}0.001 & \textless{}0.001 & \textless{}0.001 & \textless{}0.001 & \textless{}0.001 & \textless{}0.001 \\ \hline \end{tabular}
\end{table} 
Table 3: Concentrations of available macronutrients of soil treatments before the pot experiment with white clover. Treatment of the acid and alkaline soil, respectively, with: AcB and AIB: bentonite-treated sludge; AcV and AIV: vermiculite-treated sludge; AcBc and AIBc: biochar-treated sludge; AcL and AIL: lined sludge; AcD and AID: air-dried sludge; AcIF and AIIF: N-P-K inorganic fertilization; AcC and AIC: control. Different letters, within each soil and property, indicate significant differences among means, using the LSD test, at \(p\leq 0.05\). treated or untreated sludge in comparison to the control (Table 4). Although in all cases B remained below or within the sufficiency range for most crops (0.5-2 mg kg\({}^{-1}\)) [34], the 1.5-3 times increase observed in certain treatments, and especially those with the air-dried sludge, is of concern since the range values of B deficiency-sufficiency-toxicity are too close to each other (0.5 mg kg\({}^{-1}\); 0.5-2 mg kg\({}^{-1}\); >2 mg kg\({}^{-1}\)) [43]. The same trends, observed for the soil-available metals and B of the initial treatments of both soils, were also observed, and after the pot experiment. It should be mentioned that the aforementioned increases in Zn and B persisted.