Agriculture is estimated to generate about 700 million tons of waste annually in the EU. Novel valorization technologies are developing continuously to recover and recycle valuable compounds and nutrients from waste materials. To close the nutrient loop, low-value agri-food wastes, co-products and by-products (AFWCBs) produced during the valorization process, need to be returned to the soil. However, knowledge on their reaction in soils that is needed to allow efficient and environmentally sound recycling is largely lacking. To this end, we set up a series of laboratory incubation experiments using 10 AFWCBs including insect frass residues made from three different feedstocks, anaerobic digestates from two feedstocks, potato-pulp, rice bran compost, duckweed and two reference crop residues (wheat straw and sugar beet) and measured net N release, C mineralization, dehydrogenase activity (DHA), microbial biomass C (MBC) and community structure. The suppressing potential of frasses and digestates against Rhizoctonia solani was determined using bean. The digestates released the highest net mineral N (50–70%) followed by rice bran compost (55%) and duckweed (30%), while frass made from general food waste and potato-pulp immobilized N like the reference straw for 91 days after incubation. All AFWCBs except digestates significantly increased MBC compared to the control while frasses, potato-pulp and duckweed increased DHA. Frasses and digestates significantly suppressed the development of Rhizoctonia solani in bean plants. AFWCBs from emerging valorizing technologies have the potential to improve microbial activities, C sequestration and may play a significant role in closing the nutrient loop.

据估计，农业每年在欧盟产生约7亿吨废物。不断开发新的增值技术，以从废料中回收和再循环有价值的化合物和营养。为了封闭养分循环，需要将在增值过程中产生的低价值农业食品废物，副产品和副产品（AFWCB）返回土壤。但是，对于有效地和无害环境的回收所必需的关于它们在土壤中反应的知识非常缺乏。为此，我们使用10种AFWCB建立了一系列实验室孵化实验，包括从三种不同原料制得的昆虫残渣，两种原料的厌氧消化物，马铃薯浆，米糠堆肥，浮萍和两种参考农作物残渣（小麦秸秆和甜菜）和测得的净氮释放量，C矿化，脱氢酶活性（DHA），微生物生物量C（MBC）和群落结构。抑制和解冻食物的潜力用豆测定茄根霉。消化液释放出最高的净矿质氮（50-70％），其次是米糠堆肥（55％）和浮萍（30％），而普通食物废料和马铃薯纸浆固定的氮像参考秸秆一样持续了91天孵育后。与对照相比，除消化物外，所有AFWCBs的MBC均显着增加，而薯条，马铃薯纸浆和浮萍的DHA则增加。分解和消化显着抑制了豆科植物茄状枯萎病的发生。来自新兴的增值技术的AFWCB具有改善微生物活动和固碳的潜力，并可能在封闭营养循环中发挥重要作用。