# Agricultural Waste-Based Biochar for Agronomic Applications
## 3 Biochar as a Soil Amendment
### Impacts of Biochar on Heavy Metals and Chemicals Pollution Remediation 3.6.1. Heavy Metals
#### 3.6.2 Pesticide  
The ability of biochar to lower the bioavailability of pesticides in soils has been widely reported [29, 175]. [PERSON] et al. [176] showed that biochar application can significantly increase herbicide sorption but reduce herbicide efficacy. The adsorption of pesticide on biochar mainly depends on the properties of biochar used for remediation. Biochars prepared at higher temperatures present generally higher affinity to adsorb organic pesticide due to electrostatic attraction between organic pollutants and charged surfaces of \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Feedstock** & **Contaminants** & **Application Rate** & **Removal Efficiency (\%)** & **Ref.** \\ \hline \multirow{2}{*}{Sugarcane bagasse} & Cd, Cr & 15 g/kg (\(\omega\)/\(w\) basis) & Decrease in the availability of Cr- and Cd in soil by 85 and 63\% & [160] \\ \hline \multirow{2}{*}{Palm} & Cd, As & 0 and 1.5 t/ha/each & Decrease in Cd by 43–67\% and As by season & [161] \\ \hline \multirow{2}{*}{Wheat straw} & Cd, Pb & 0, 20, and 40 t/ha & Decrease in Cd by 6–14\% in years 1 and 3 & \\  & & & and Pb by 24–67\%, no significant reduction & [162] \\  & & & at higher biochar application rate & \\ \hline \multirow{2}{*}{Poplar woodchips} & Cd, Pb, Zn & 0, 1\% & Decrease in Cd by 75\%, Pb by 86\% and Zn by 92\% & [163] \\ \hline \multirow{2}{*}{Rape straw and rice straw} & \multirow{2}{*}{Pb, Cu} & \multirow{2}{*}{0, 2\% and 5\%} & Reduction in the mobility and & \\  & & & phyto-availability of Pb and Cu in two years & \\  & & & Decrease in the concentration of Pb by & \\  & & & 40.81\% and Cu by 56.14\% in plant tissues & \\ \hline \multirow{2}{*}{Rice straw} & Cd & 0, 10 t/ha and20 t/ha & Reduction in the Cd concentration by & \\  & & & 8.6–50.2\% & \\ \hline \multirow{2}{*}{Rice straw} & Cd, As & - & The maximum removal rate of Cd(II) was & \\  & & & 98\% and that of As(III) is 85\% & \\ \hline \multirow{2}{*}{Sugarcane bagasse} & Cd, Pb, Cu & 1.5, 2.25 and 3.0 t/ha & Decrease in Cd by 62–76\%, Pb by & \\  & & & 17.3–49.1\% and Cu by 15–38\% in shoot & \\ \hline \multirow{2}{*}{Wheat straw} & \multirow{2}{*}{Cd} & \multirow{2}{*}{0, 20 and 40 t/ha} & Reduction in rice grain Cd by 61, 86 and & \\  & & & 57\% over three seasons & \\  & & & Reduction in available soil Zn by 35–91\% & \\ \hline \multirow{2}{*}{Sewage sludge} & \multirow{2}{*}{As, Cd, Cu, Pb and Zn} & \multirow{2}{*}{5\%, 10\% (\(w\)/\(w\))} & In comparison to the control PTE: & \\  & & & Reduction in the accumulation in grain of & \\  & & & Asby 60.2–67.5\%, of Cd by 26.5–42.0\% of Cu & \\  & & & by 24.0–29.3\% of & \\  & & & Pb by 32.5–37.7\% and of Zn by 16.6–22.0\% & \\ \hline \multirow{2}{*}{Wheat straw} & Cd, Pb & 0, 10, 20, 40 t/ha & Reduction in Cd by7.5–23.3\% and in Pb by & \\  & & & 3.7–19.8\% & \\ \hline \multirow{2}{*}{Wheat straw} & \multirow{2}{*}{Cd} & \multirow{2}{*}{782 kg/ha} & Reduction in the exchangeable Cd by 28.6\% & \\  & & & in soil and decrease in the Cd & \\  & & & bioaccumulation factor from 0.36 to 0.32 & \\ \hline \multirow{2}{*}{Chicken manure, rape straw} & \multirow{2}{*}{Cd} & \multirow{2}{*}{1\%, 5\%, 10\%,15\% (\(w\)/\(w\))} & Reduction in Cd concentration in soil by & \\  & & & 11.64–16.3\% at an application rate of 15\% & \\  & & & Reduction in Cd uptake by maize shoots at & \\  & & & application rates of 1\% and 5\% & \\ \hline \multirow{2}{*}{Rice straw} & \multirow{2}{*}{Cd} & \multirow{2}{*}{0, 10, 20 t/ha} & Cd immobilization in soil increased with & \\  & & & increasing amounts of applied biochar & \\ \hline \multirow{2}{*}{Miscanthus} & \multirow{2}{*}{Ni} & \multirow{2}{*}{3, 4, 5\%} & Reduction in the concentrations of Ni in & \\  & & & spinach tissues and in soil with the increase & \\  & & & in biochar rate, however no significant & \\  & & & changes were observed below 3\% rate & \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Removal of heavy metals from soils at different rates of biochar application. biochars [29; 177; 178].