Physicochemical Properties of Organic Liquid Fertilizer with Oil Cake and Rice Bran as Affected by Microorganism and the Ratio of Molasses

The study was conducted to investigate changes in the characteristics of inorganic components during fermenting process of organic liquid fertilizers according to the type and ratio of microorganism and the amount of molasses when producing organic liquid fertilizers using sesame oil cake and rice bran. To select appropriate microorganisms, liquid fertilizers were produced through a 90-day fermentation process by adding mag-ggeo-li, yogurt, dried yeast, and leaf mold. The pH in liquid fertilizer was decreased, and then increased in all microorganism samples except the mag-ggeo-li sample. The EC was rapidly increased in all samples until the 10th days after production, and showed no changes after the 60 th days in dried yeast and after the 30 th days in the other samples. The concentration of NH₄-N was generally increased with time. The concentration of P₂O? was rapidly increased until the 10 th days after production and was maintained at about 1% regardless of the type of microorganism. In terms of the characteristics of liquid fertilizers according to the ratio of selected dried yeast, the pH was decreased until the 30 th days after producing the liquid fertilizers, and then was increased regardless of the ratio of dried yeast. The EC was increased with time and showed no differences depending on the amount of dried yeast. The concentration of NH₄-N was increased with time and in proportion to the amount of dried yeast. In terms of the characteristics of liquid fertilizers according to the ratio of molasses, the pH was decreased with increasing the molasses. The EC and concentration of P₂O? were no differences according to the amount of molasses. When 3% molasses was added, the content of NH₄-N was 2.6 mg L -1 at the beginning and was at 3,025 mg L -1 on the 90th days.