Effect of pyrolysis temperature on eucalyptus wood residues biochar on availability and transport of hexazinone in soil

Pyrolysis Temperature vs. Application Rate of Biochar Amendments: Impacts on Soil Microbiota and Metribuzin Degradation

“…In contrast, the degradation of the non-ionizable herbicide oxyfluorfen applied in pre-emergence was faster (DT 50 of 2 days and 23 days) with the addition of rice husk biochar produced at 500 • C, at an application rate of 2%, than in unamended soil [15]. Different application rates of hardwood biochar showed positive effects on the mineralization of 14 C-atrazine in Brazilian soil, representing increases of 50% (0.1% w/w), 48% (1.0% w/w), and 46% (5.0% w/w) compared to unamended soil [16]. The high persistence of herbicides in soils amended with biochar, due to the unavailability of the molecules in the soil solution for microorganisms, can significantly alter biodegradation processes; however, degradation responses are dependent on the physicochemical characteristics of the herbicide, biochar production, and soil type [1,17].…”

“…Biochar-amended soils can directly influence the degradation half-life time (DT 50 ) of herbicide depending on the molecule, pyrolysis temperature, application rate, and feedstock used [ 1 ]. For example, the total amount of hexazinone (mineralized residue + non-extracted or bound residue) in soils amended with biochar from eucalyptus wood waste produced at pyrolysis temperatures of BC850 °C (46%) and BC950 °C (49%) was higher compared to biochar produced at BC650 °C (33%) and BC750 °C (42%) [ 14 ]. In contrast, the degradation of the non-ionizable herbicide oxyfluorfen applied in pre-emergence was faster (DT 50 of 2 days and 23 days) with the addition of rice husk biochar produced at 500 °C, at an application rate of 2%, than in unamended soil [ 15 ].…”

Degradation Process of Herbicides in Biochar-Amended Soils: Impact on Persistence and Remediation

“…These conflicting results could be due to the impact of ash on the alkalinity of the soil amended with biochar produced at 700°C (20.3% of ash), which increased the soil pH and improved the conditions for the degradation of metribuzin, and to the greater amount of dissolved OC from biochar produced at 350°C (3.78 mg g −1 ), which is more preferred by microorganisms as substrate, increasing the persistence of the herbicide. The variation in pyrolysis temperature of eucalyptus wood residue biochar affected the total hexazinone unavailable (mineralized + non-extractable residue) being higher for 850°C (46%) and 950°C (49%) compared to biochar pyrolised at 650°C (33%) and 750°C (42%) [71]. The addition of biochar did not alter the mineralization of hexazinone, but it did reduce the bioavailability of this herbicide in the soil due to the greater amount of nonextracted residue, reducing the risk of environmental contamination [71].…”

“…The variation in pyrolysis temperature of eucalyptus wood residue biochar affected the total hexazinone unavailable (mineralized + non-extractable residue) being higher for 850°C (46%) and 950°C (49%) compared to biochar pyrolised at 650°C (33%) and 750°C (42%) [71]. The addition of biochar did not alter the mineralization of hexazinone, but it did reduce the bioavailability of this herbicide in the soil due to the greater amount of nonextracted residue, reducing the risk of environmental contamination [71].…”