Table 1: Total and mineral nitrogen contents of fishery waste-derived fertilising products selected for soil incubation
Nitrogen (N) use efficiency and the ability of bio-based fertilisers (BBFs) to substitute mineral fertilisers is dependent on the N speciation of applied N to the soil. Moreover, the environmental safety of N fertilisers depends on their risks towards losses either by leaching or volatilizing. To assess mineralisation patterns, N release dynamics of selected fishery waste-derived BBFs were assessed and compared with mineral fertilisers in soil incubation assays under controlled conditions for 120 days. The NH4+-N added via the BBF products was completely nitrified as was observed by the negligible concentrations of NH4+-N and a strong increase in the levels of NO3–N.
All tested fishery waste-derived fertilising products had lower mineral N content compared to that of synthetic fertiliser (Calcium Ammonium Nitrate) and liquid pig manure (Man). BBF products ‘NPK’, ‘PH’, ‘FSP’, ‘FMP’ and ‘PF’ had comparatively higher net N-release and N-mineralisation at the end of the incubation period. The presence of amino acids and/or other protein fractions in these fertilising products led to a higher N-release and N-mineralisation rate in the incubation tests.
Figure 1: Net N-release at 20th day and 120th day
Figure 2: Net N-mineralization at 20th day and 120th day
Further information: Zhang et al., 2023. Quality and safety assessment of fertilising products derived from fishery waste and by-products. Wageningen Soil Conference – Book of Abstracts, p93-94. https://wageningensoilconference.eu/2023/wp-content/uploads/2023/08/Book-of-abstracts-WSC2023