Crop residue biochar’s role in healthy soil and food production: the potential tool to assist organic farming

Biochar’s multifaceted benefits for soil quality have been well acknowledged whilst its particular effects on plant health have not yet been thoroughly understood. Plant health is conceived as the plant capacity of resource efficient production, of tolerance to abrupt stresses by extreme weather events, of bio-control or bio-defense of soil-borne pathogens and of safe synthesis of functional compounds for food quality and human nutrition. Biochar soil amendment provided quick restoration of soil organic matter, soil structure build-up and stabilization of toxic metals and organic pollutants in soil, benefiting safe growth of crops.  Utilization of biochar for blending mineral nutrients creates slow releasing fertilizers so as to increase nutrient use efficiency and reduce the fertilizer dosage while supplement OC and minor elements to soil. Moreover, use of biochar for co-composting animal wastes to produce novel biochar-based composts is shown an useful application of biochar in organic agriculture. In addition, biochar use in anerobic digestion and as sorbent in waste water and waste slurry is being explored in rural sector. As a particular case for rice crop production, biochar from rice residue to healthy paddy and rice can be managed into a closed loop: rice straw feeding cows and the manure into biochar-compost for soil amendment (reducing methane emission from residue incorporation), rice husk gasification for bioenergy for energy displacement and biochar for blending chemical fertilizers (reducing nutrient release to waters and nitrous oxide emission) for rice production, all these promoting healthy rice production.  improvement). It could be a biochar-centralized bioeconomy in agriculture could become a global solution for reverse soil degradation, environment pollution and soil C loss while significantly mitigating the climate change. The scope and standardization of biochar for crop production should be a research priority for biochar science and technology in agriculture.