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

Biochar is a solid material derived from different feedstocks that is added to the soil for various agronomic and environmental purposes, such as nutrient sources and CO2 emission mitigators. In modern agriculture, the application of herbicides directly in the soil is common for pre-emergent weed control; however, biochars may interfere in the degradation processes of these agrochemicals, increasing or decreasing their persistence. Long persistence is desirable for some herbicides in determined cultivation systems, especially in monoculture, but persistence is undesirable in crop rotation and/or succession systems because the subsequent cropping can be sensitive to the herbicide, causing carryover problems. Therefore, knowing the interactions of biochar-herbicide is essential, since these interactions depend on feedstock, pyrolysis conditions (production temperature), application rate, biochar aging, among other factors; and the physical-chemical characteristics of the herbicide. This chapter shows that the addition of biochar in the soil interferes in the persistence or remediation processes of the herbicide, and taking advantage of the agricultural and environmental benefits of biochars without compromising weed control requires a broad knowledge of the characteristics of biochar, soil, and herbicide and their interactions.