Mediterranean ecosystems are threatened by water and nutrient scarcity and continuous loss of soil organic carbon. Urban agglomerations and rural ecosystems in the Mediterranean region and globally are interlinked through the flows of resources/nutrients and wastes. Contributing to balancing these cycles, the present study advocates standardized biochar as a soil amendment, produced from Mediterranean suitable biowaste, for closing the nutrient loop in agriculture, with parallel greenhouse gas reduction, enhancing air quality in urban agglomerations, mitigating climate change. The study’s scope is the contextualization of pyrolytic conditions and biowaste type effects on the yield and properties of biochar and to shed light on biochar’s role in soil fertility and climate change mitigation. Mediterranean-type suitable feedstocks (biowaste) to produce biochar, in accordance with biomass feedstocks approved for use in producing biochar by the European Biochar Certificate, are screened. Data form large-scale and long-period field experiments are considered. The findings advocate the following: (a) pyrolytic biochar application in soils contributes to the retention of important nutrients for agricultural production, thereby reducing the use of fertilizers; (b) pyrolysis does not release carbon dioxide to the atmosphere, contributing positively to the balance of carbon dioxide emissions to the atmosphere, with carbon uptake by plant photosynthesis; (c) biochar stores carbon in soils, counterbalancing the effect of climate change by sequestering carbon; (d) there is an imperative need to identify the suitable feedstock for the production of sustainable and safe biochar from a range of biowaste, according to the European Biochar Certificate, for safe crop production.

中文翻译：

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平衡城市群和农村生态系统之间的废物和营养流：生物炭，用于改善地中海地区的作物生长和城市空气质量

地中海生态系统受到水和养分稀缺以及土壤有机碳持续流失的威胁。地中海地区乃至全球的城市群和农村生态系统通过资源/养分和废物的流动相互联系。为了平衡这些循环，本研究提倡使用标准化的生物炭作为土壤改良剂，由地中海适宜的生物废料生产，用于封闭农业中的营养循环，同时减少温室气体排放，提高城市群的空气质量，缓解气候变化。这项研究的范围是热解条件和生物废料类型对生物炭产量和特性的影响，并阐明生物炭在土壤肥力和减缓气候变化中的作用。根据通过欧洲生物炭证书批准用于生产生物炭的生物质原料，筛选了用于生产生物炭的地中海型合适原料（生物废料）。考虑了大规模和长期现场实验的数据。研究结果主张以下几点：（a）在土壤中热解生物炭的使用有助于保留农业生产中的重要营养素，从而减少了肥料的使用；（b）热解不会将二氧化碳释放到大气中，有利于平衡向大气排放的二氧化碳，并通过植物的光合作用吸收碳；（c）生物炭将碳储存在土壤中，通过隔离碳来平衡气候变化的影响；