The number of certified producers in Japan is stagnant. Compared to European countries, the organic products and food markets are supported only by the demand of some consumers, and it is thought that there are many situations in which trust promoted by close mutual relation works effectively. However, when organic farming takes a leap forward, it is necessary to merge the historical identity of organic farming and certification system. Looking at the experience in France, the fusion of the two can be summarized as follows. First, the prototype of the certification system was established through the activities and practices of organic farmers. It was created as a grassroots innovation, not only by an official and top-down decision making. Secondly, it was found that the certification system for organic agriculture is integrated in a portion of food quality policy that includes geographical indications. Third, even in the case of a participatory guarantee system, which emphasizes the principle of organic agriculture, ensuring the maximum transparency and confirming implementation to eliminate the asymmetry of information is the primary characteristic of the mechanism. Therefore, coexistence of both historical identity of organic farming and certification system are made up of the continuous efforts and trial and error.

In this study, the amounts of SO₄-S released from various organic fertilizers, which are commonly utilized for organic farming in Japan, were determined via an incubation method. The total S content of 25 varieties of fertilizers, including plant matter, animal matter, livestock manure compost, poultry manure compost, and garbage compost, was measured. The fertilizers with excessively low S contents were excluded from the subsequent analysis. The remaining 17 varieties of fertilizers were subjected to incubation. Initially, they were coarsely crushed to particle sizes of 2mm or lower. Thereafter, an amount of fertilizer corresponding to a total S content of 1mg was mixed with 20g of air-dried soil (light-colored Andosol). Subsequently, water was added up to 60% of the maximum water holding capacity of the soil. The soil-fertilizer mixtures in 100mL glass bottles were incubated for 0, 4, 8, and 12 weeks at 30°C. The release patterns of SO₄-S over time were complicated and nonuniform; furthermore, they differed depending on the variety of fertilizer. Nine varieties of fertilizers released the highest amounts of SO₄-S at 4 weeks of incubation. The amounts of released SO₄-S from 14 varieties of fertilizers increased with an increase in the incubation time from 0 to 4 weeks. Substantial amounts of SO₄-S (3.00gkg^－1 FW or more) were released from rapeseed oil cake, fishmeal, and fermented chicken manure at 4 weeks of incubation. Multiple regression analysis was performed with the measured amount of released SO₄-S as the dependent variable and the contents of SO₄-S and non-SO₄-S (total S minus SO₄-S) as the independent variables. The results revealed that R² was 0.85 or higher at 4, 8, and 12 weeks of incubation.