Biochar-enhanced soilless farming: a sustainable solution for modern agriculture

Current agricultural practices face significant challenges, including depleting arable land, water scarcity, changing climatic conditions, and heavy use of chemical fertilizers and pesticides. Soilless farming (SLF), such as hydroponics, offers a sustainable alternative to conventional farming, by growing crops in nutrient solutions and soilless substrates, using up to 90% less water and land while reducing greenhouse gas emissions. However, SLF often relies on less sustainable substrates like peat, vermiculite, and rock wool; there is a need to introduce a more sustainable substrate that also fits into the circular economy. Biochar, produced through the high-temperature pyrolysis of waste biomass, presents a promising solution by enhancing water and nutrient retention, suppressing plant diseases, reducing GHG emissions, and providing a habitat for beneficial microbes. Despite initial high investment and energy consumption challenges, advancements in affordable kiln technology have made biochar production more cost-effective.

This review highlights the transformative potential of integrating biochar into SLF to create a resilient and sustainable agricultural system. It discusses the significance of SLF, the potential of biochar as a substrate, its interactions with microbes, its role in enhancing plant growth and reducing environmental carbon load. Additionally, the review covers the criteria for commercial biochar production, utilization, its economics and the associated challenges in biochar use.