Technological watch

Intensification of production across agriculture, horticulture, forestry, biodiversity restoration and other plant-related industries is urgently needed to meet expanding demand for food and materials, sustainability and climate change targets and to remain profitable under harsh post-pandemic conditions. This review appraises biochar, a charcoal-like material consisting largely of recalcitrant carbon, as a vehicle to assist such industries in meeting productivity, sustainability and economic goals. Biochar is inherently complex and there remains uncertainty surrounding its commercial viability. Hence the review unravels scientific and techno-economic understanding of barriers to biochar use and steps to address shortcomings. Raw biochar is demonstrated as a poor investment because it unpredictably accumulates compounds that have positive, negative or neutral influences on plants and microbes depending on chemical ratios formed and phyla-specific sensitivity to such chemistry, while soil incorporation of raw biochar has unrealistic payback times (15–125 years), even with crop yield increases. The good news is that momentum is building to overcome the most pressing issues. Biochar standardisation is imperative and technologies to remove or prevent the formation of contaminants are already in development. Bioengineering biochar into upscaled profitable commodities (such as compound fertilizers) is already minimising payback times and simultaneously promoting plant, microbe, soil and environmental benefits. Closing the circular economy by reusing waste, cleverly managing nutrients, co-producing energy and using parallel technologies (such as anaerobic digestion) has already enhanced system efficiency and profitability. Thus, this review focuses industry, research and policy makers towards strategic opportunities that will maximise biochar benefits and profitability across industry sectors.