A Critical Review on Advancement and Challengesof Biochar Application in Paddy Fields: Environmental and Life Cycle Cost Analysis

• Paddy fields emit considerable amounts of methane (CH4), which is a potent greenhousegas (GHG) and, thereby, causes significant environmental impacts, even as they generate wealth andjobs directly in the agricultural sector, and indirectly in the food-processing sector. Application ofbiochar in rice production systems will not just help to truncate their carbon footprints, but alsoadd to the bottom-line. In this work, the authors have reviewed the literature on climate change,human health, and economic impacts of using organic residues to make biochar for the additionto croplands especially to rice paddy fields. Biochar-bioenergy systems range in scale from smallhousehold cook-stoves to large industrial pyrolysis plants. Biochar can be purveyed in dierentforms—raw, mineral-enriched, or blended with compost. The review of published environmental lifecycle assessment (E-LCA) studies showed biochar has the potential to mitigate the carbon footprint offarming systems through a range of mechanisms. The most important factors are the stabilization ofthe carbon in the biochar and the generation of recoverable energy from pyrolysis gases produced asco-products with biochar as well as decreased fertiliser requirement and enhanced crop productivity.The quantitative review of E-LCA studies concluded that the carbon footprint of rice produced inbiochar-treated soil was estimated to range from -1.43 to 2.79 kg CO2-eq per kg rice grain, implying asignificant reduction relative to rice produced without a biochar soil amendment. The suppressionof soil-methane emission due to the biochar addition is the dominant process with a negativecontribution of 40–70% in the climate change mitigation of rice production. The review of the lifecycle cost studies on biochar use as an additive in farmlands demonstrated that biochar applicationcan be an economically-feasible approach in some conditions. Strategies like the subsidization ofthe initial biochar capital cost and assignment of a non-trivial price for carbon abatement in futurepricing mechanisms will enhance the economic benefits for the rice farmers.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Environmental Sciences (hsv//eng)

Nyckelord

rice cropping systems; biochar; pyrolysis gas; E-LCA; carbon abatement; human health; economic analysis

Kemi

Chemistry

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