Development of Marine Fertilizer Made from Ripened Chicken Manure Compost

In the Seto Inland Sea, oligotrophication due to the long-term reduction measures of nitrogen and phosphorus, which is evidenced by the discoloration of nori laver and a decrease in fishery production, is pointed out. In this study, we developed a fertilizer that can elute nutrients required for the growth of marine organisms. The main ingredient of this fertilizer is chicken manure, to which steel slag and hardener were added, followed by pressing to form a solid fertilizer. To establish the proper N/P/Fe elution ratio for the growth of microalgae, elution tests using 500 L flasks were carried out with fertilizer pieces of different ingredient mixed ratios. A long-term elution test was also performed using the actual size fertilizer (25 cm diameter and 23 cm height) in 100 L containers under flow-through seawater systems. Elution of nutrients continued for longer than 5 months. It is concluded that the fertilizer developed in this study is useful for enhancing the growth of marine organisms.