Nitrogen Availability in Organic Fertilizers from Tannery and Slaughterhouse By-Products

Agriculture can play a primary role in the context of nutrients recovery by promoting use organic fertilizers (OFs). In order to them efficiently, it is necessary predict nitrogen (N) bioavailability, which challenging matter due different physical-chemical characteristics commercially available OFs. This study aims evaluate hot-water extractable N as rapid and cheap chemical indicator bioavailable N. The trial was conducted on nine animal-based OFs obtained from raw materials treatment processes. They were fully characterized determined 7-week soil incubation experiment. results showed that underestimated case leather meal based OFs; however, significant linear regression fitting achieved (R2 = 0.53). C:N ratio also assessed, negative correlation (−0.87) better 0.76) with N, but manifested some limitations prediction products. experiment both provide useful information for farmers managing this class