Bærekraftig gjødsel

Summary

This lecture explains some basic characteristics of the elements nitrogen (N), phosphorus (P) and potassium (K), and their important role as macronutrients for crop plants. Further, the significant contribution of current agricultural systems to overload the planetary boundaries for biochemical flows of N and P are discussed. The lecture then presents fertilisers derived from marine residual materials which are currently poorly utilised (bone-rich material from fish; seaweed residues). Raw materials are discussed, along with results of pot and field trials carried out with marine materials. Fish residues were applied as NPCa-fertilisers around 1910, with significant export of fish-based "guano" from Norway.