## 6 Conclusions  
The major effects of biochar application on soil physical, chemical, and biological characteristics are summarized in Table 5. Regarding the objective of the present review, we have highlighted the benefits and some drawbacks of biochar application. Most of the literature shows that biochar generally contributes to improvement of physicochemical properties in soils, such as their water balance, clay, organic matter content, pH buffering, and the amounts of macro-, meso-, and several microelements, due to its porous structure, aeration, oxygen content, and relative quantity. The available literature indicates, therefore, a wide range of uses of biochar for the development and enhancement of beneficial soil \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Soil Characteristics** & **Advantages of BC** & **Disadvantages of BC** & **Suggestions to Treat** \\ \hline \multicolumn{4}{c}{**Soil physical conditions**} \\ \hline \multirow{3}{*}{Texture, porosity} & - BC can be used to improve soil quality [21, 86] & - Soil type is crucial in positive effect [29, 30, 31, 32] & - Soil type is crucial in positive effect [29, 30, 31, 32] & - Previous selection and study needed to avoid improper use \\ \hline \multirow{3}{*}{Surface area, plant-nutrition} & - Adsorption and fixing of elements or leachable materials (e.g., nitrate) [37] & - Plant nutrition might be limited (e.g., in drought conditions) [38, 39] & - Consider the stressed environmental condition (watering, soil inoculation) \\ \hline \multirow{3}{*}{Aeration, better oxygenation} & - Supports aerobic processes, protects soil biota [2, 3] & - Potential of reduced SOM and humans content [42] & - Use soil-dependent treatments, add organic materials \\ \hline \multicolumn{4}{c}{**Soil chemistry**} \\ \hline \multirow{3}{*}{pH} & - Near-neutral conditions, better for the soil life [100] & - Some nutritive elements become less available [36] & - Consider current soil characteristics and act accordingly \\ \hline \multirow{3}{*}{SOM, humus, carbon} & - Sequesters carbon [4, 5] & - Indirect effect on soil biota might reduce SOM [63, 64] & - Proper use might be required \\ \hline \multirow{3}{*}{Toxic materials, heavy metals} & - Improved decontamination [16, 81, 89] & - Propured decontamination - Retault accumulation of toxic compounds [5] & - Inoculation by adapted microbes might improve remediation \\ \hline \multicolumn{4}{c}{**Soil biology**} \\ \hline \multirow{3}{*}{Survival of soil biota} & - Large surfaces can provide niche [65, 66, 67] & - Dependence on microbial physiological groups [98] & - Focus on soil-borne plant pathogens might be helpful \\ \cline{1-1}  & - Drought protection and improved stress tolerance [70, 84, 88] & - Limitation in microbial distribution [12] & - Proper C:N ratio to avoid penthozan effect \\ \hline \multirow{3}{*}{Activity of soil biota} & - Enhanced plant nutrition & - Competition with plants for nutrients [43] & - Optimization for specific soil–plant systems \\ \cline{1-1}  & & & \\ \end{tabular}
\end{table} 
Table 5: Summary of possible advantages and disadvantages of biochar application in various soil–plant systems with suggested solutions. plant-microbial interactions. Improvements in plant nutrition may occur via several direct and indirect effects in soils. We have to mention, however, that intensification of soil biological activity is frequently a drawback of biochar application in some soils that are relatively low in soil organic matter and high in aeration, such as the aerosols. In arid environmental conditions, it is the limited water availability that is able to diminish known beneficial effects and reduce the potential nutrient uptake by crops. Integration of biochar into crop production technologies therefore requires preliminary experiments, particularly in considering the effects of symbiotic beneficial bacteria and fungi.