Assessing the Effects and Environmental Implications of Biochar Amendment in Agricultural Soils

Abstract

In recent years, the production and use of biochar have been increasing rapidly, and the biochar market is projected to continue growing between 2019 and 2025. Given that biochar has a long residence time in the environment (soil), a systematic review was conducted to assess the major environmental impacts of its application in agricultural soils. The results were largely consistent in indicating the positive effects of biochar on soil fertility, moisture content, and microbial communities. Moreover, biochar has been shown to improve soil physical properties and provide habitats for soil microorganisms. Biochar application in soil has the potential to mitigate climate change and reduce human health risks. However, the oxidation and ageing process of biochar has the potential to lead to the absorption, accumulation, and release of environmental pollutants such as heavy metals, polycyclic aromatic hydrocarbons (PAHs), dioxins, environmentally persistent free radicals (EPFRs), perfluorochemicals (PFCs), and volatile organic compounds (VOCs) depending on the type of biomass used. Therefore, when considering biochar application in soil for agricultural purposes, it is important to consider the biomass type and investigate the potential negative secondary environmental consequences.