Application of Marine-derived Materials as Biofertilizers in Organic Farming

Significant volumes of materials from fish, seaweed and other marine organisms are poorly utilized and may be well suited for application as fertilizers and soil amendments. Brown seaweed contains significant amounts of potassium and calcium, and bone-rich residues from white fish are rich in nitrogen and phosphorus. Together, such materials are a good starting point for a well-balanced complete fertilizer, applicable for arable and feed crops. At NORSØK, several studies have been carried out in recent years with such materials as soil amendments. Whereas fish residues have a remarkably rapid and positive effect on crop growth, seaweed residues have a remarkable residual effect. Potentially toxic elements, especially arsenic and cadmium, need consideration when brown seaweeds are applied to soil, but we have not revealed increased uptake of these elements in crop plants grown in soil amended with seaweed.