https://www.selleckchem.com/products/odq.html 84), organic N content (r2 = 0.82), the sum of Hedley's more easily dissolved SRP (soluble reactive P) and OP (r2 = 0.95), and the total P and SRP extracted by 16 h of shaking with the bicarbonate reagent (r2 ≥ 0.90). These findings indicate that if greater P availability is desired, the stabilization of biosolids and biowastes should be minimized. These insights into the relationships between OA characteristics and P solubility may benefit the use of OAs in agricultural systems and aid assessments of the environmental significance of their use.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, pot