NOVELTY - Microbial organic fertilizer comprises Sargassum thunbergii, kelp, Asterionella glacialis, marine fish leftovers, chicken manure, cocklebur fruit cake, vermiculite powder, zinc sulfate, Streptomyces griseus, Sporotrichum thermophile, Acetobacter diazotrophicus, Nocardia atlantica, Bacillus thuringiensis, and Phanerochaete chrysosporium.    USE - The microbial organic fertilizer is useful for lettuce.    ADVANTAGE - The microbial organic fertilizer is rich in nutrients, provides long-lasting fertilization effect, improves disease resistance of seedlings, soil characteristics and quality of lettuce, increases yield of lettuce, and significantly reduces incidence of downy mildew disease in lettuce.    DETAILED DESCRIPTION - Microbial organic fertilizer comprises 49-55 pts. wt. Sargassum thunbergii, 75-81 pts. wt. kelp, 16-19 pts. wt. Asterionella glacialis, 21-25 pts. wt. marine fish leftovers, 28-35 pts. wt. chicken manure, 8-10 pts. wt. cocklebur fruit cake, 23-30 pts. wt. vermiculite powder, 10-13 pts. wt. zinc sulfate, 2-2.5 pts. wt. Streptomyces griseus, 1.2-1.5 pts. wt. Sporotrichum thermophile, 1-1.2 pts. wt. Acetobacter diazotrophicus, 1.5-1.8 pts. wt. Nocardia atlantica, 0.8-1 pt. wt. Bacillus thuringiensis, and 1.2-1.5 pts. wt. Phanerochaete chrysosporium. An INDEPENDENT CLAIM is included for preparation method of the above-mentioned microbial organic fertilizer, which involves (a) mixing the S.thunbergii, kelp, A.glacialis and marine fish leftovers in the above-mentioned weight proportions, crushing obtained mixture, and heating crushed product to 100-105 degrees C under constant stirring condition for 1-2 hours, (b) mixing the S.griseus, S.thermophile and vermiculite powder in the above-mentioned weight proportions, adding obtained mixture to product obtained in the step (a), stirring mixture uniformly, and reacting the mixture at 62-72 degrees C for 20-25 days, (c) mixing the A.diazotrophicus, N.atlantica, B.thuringiensis and P.chrysosporium in the above-mentioned weight proportions, diluting obtained mixture with water in a weight ratio of 1:10, stirring the mixture uniformly, adding chicken manure and cocklebur fruit cake in the above-mentioned weight proportions to stirred mixture, and reacting mixture at 30-35 degrees C for 15-20 days, (d) adding product obtained in the step (b) to the product obtained in the step (c), and reacting obtained mixed material at 30-35 degrees C for 10-15 days, and (e) adding zinc sulfate in the above-mentioned weight proportion to product obtained in the step (d), stirring mixture uniformly, and granulating the mixture.