The climate crisis and years of unsustainable agricultural practices have reduced soil fertility and crop yield. In addition, agricultural lands contribute more than 10% of greenhouse gases (GHGs). These concerns can be addressed by using biochar for carbon neutralization, environmental restoration, and agricultural management. Biochar has a role in nitrous oxide and methane gas emission mitigation from agricultural soil. New methods are needed to link belowground processes to functioning in multi-species and multi-cultivar agroecosystems. The intricate relationship between biochar and the composition of soil microbial communities, along with its impacts on functions within the rhizosphere, constitutes a highly perplexing and elusive subject within microbial genomics. The present review discusses how biochar can mitigate climate change, enhance carbon sequestration, and support crop productivity. Biochar could be a potential solution to mitigate soil microplastics and heavy metal contamination. Applying a biochar-based microbiome reduces polycyclic aromatic hydrocarbons (PAHs) in soil. The current knowledge and perspectives on biochar–plant–microbial interactions for sustainable agriculture and ameliorating the adverse effects of climate change are highlighted. In this review, a holistic approach was used to emphasize the utility of biochar for multiple applications with positive and negative effects and its role in promoting a functional circular economy.

Arsenic contamination in soil and water is a major problem worldwide. Inorganic arsenic is widely present as arsenate and arsenite. Arsenic is transferred to crops through the soil and irrigation water. It is reported to reduce crop production in plants and can cause a wide array of diseases in humans, including different types of cancers, premature delivery, stillbirth, and spontaneous abortion. Arsenic methyltransferase (AS3MT) in the human body converts inorganic arsenic into monomethylarsonic acid and dimethylarsinic acid, which are later excreted from the body. Arsenic transfer from the soil to grains of rice involves different transporters such as Lsi1, Lsi2, and Lsi6. These transporters are also required for the transfer of silicate, which makes them important for the plant. Different mitigation strategies have been used to mitigate arsenic from crops, such as plant growth-promoting bacteria, fungi, and nanoparticles, as well as using different plant genotypes and plant extracts. Different factors such as nitric oxide, Fe, and jasmonate also affect the response of a plant to the oxidative stress caused by arsenic. This review highlights the various effects of arsenic on plants with respect to their biochemical, molecular, and physiological aspects and the employment of classical and innovative methods for their mitigation. The current review is expected to initiate further research to improve As remediation to mitigate the effect of heavy metal pollution on the environment.