生物质炭服务农田生态系统“碳中和”的机制和潜力研究进展
Mechanisms and Potential of Biochar to Serve ‘Carbon Neutrality’ in an Agroecosystem: A Review
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摘要: 废弃植物生物质热解制备为生物质炭是碳源整合再利用的有效手段之一,既能减少生物质自然分解过程中CO2排放,同时,生物质炭还田还可通过调控微生物活动和碳源利用效率减少土壤本底有机碳矿化. 此外,生物质炭对土壤通气性的改善有利于CH4氧化;其多孔结构、高比表面积等性能有利于CO2及可溶性有机碳等易损耗碳源的吸附固定,促进土壤有机碳的固持,增加土壤碳库容量和质量. 在农田生态系统中合理施加生物质炭有利于提高植物光合固碳能力、增加植物生物量和作物产量,具有环境和经济双重效益. 因此,生物质炭可借助土壤和植物两条途径助力农田生态系统中的碳减排增汇. 然而,生物质炭的内源性污染物、异质性和持久性等导致其很可能具有长期的生态环境风险,仍需深入而广泛的研究. 环境友好型生物质炭的制备、生物质炭的因地制宜策略等仍然是亟待解决的难题. 未来研究建议在生物质炭促生增碳的相关机理、生物质炭的长期生态效应、生物质炭基“智慧土壤”的研发以及生物质炭制备工艺标准化和生产规模化等方面加强,实现生物质资源的高效整合与绿色应用,以期助力生物质炭还田技术的推广,更好地服务“碳中和”战略.Abstract: Pyrolysis of waste biomass to produce biochar is one of the critical technologies for recycling and reuse of biomass carbon, which benefits carbon neutrality. Pyrolysis of waste plant biomass into biochar reduces CO2 emissions derived from the natural decomposition of biomasses. In addition, a rational application of biochar can mediate microbial activities and benefit the carbon utilization efficiency of microorganisms, reducing the mineralization of soil organic carbon and the resultant CO2 emissions. Moreover, biochar application can improve soil aeration, which is conducive to increasing the biological oxidation of CH4. Since biochar has a porous structure, high specific surface area, and abundant functional groups, it can adsorb and fix carbon resources that are easily lost such as CO2-carbon and dissolved organic carbon in soils, increasing soil carbon pool and quality. Furthermore, a rational application of biochar also benefits photosynthesis and regulating genes involved in plant metabolism and growth, which contributes to increasing plant biomass and crop yields. Therefore, biochar application has both environmental and economic benefits. To sum up, biochar shows great potential to serve “carbon neutrality” in an agroecosystem with the two brushes of “aboveground growth promotion” and “underground carbon-pool promotion”. However, the endogenous pollutants, heterogeneity, and persistence of biochar suggest that biochar is likely to have long-term ecological and environmental risks. How to produce environment-friendly biochar, how to select the appropriate type and application dosage of biochar, and how to apply biochar adapting to local soil conditions are still important challenges to date. In future research, the mechanisms of biochar increasing soil carbon sequestration and the resultant long-term ecological effects should be further investigated. In addition, since biochar shows excellent effects on plant growth and soil improvement, kinds of “functional soil” based on biochar are suggested to be developed. A standardized and large-scale biochar production should be expanded to achieve efficient integration of waste biomass resources and the green production of biochar. A criterion for rational application of biochar will guarantee the sustainable service of biochar for “carbon neutrality”.
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Key words:
- Soils /
- Carbon neutrality /
- Biochar /
- Crops /
- Waste biomass
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