NOVELTY - Specialized calcium organic fertilizer comprises (in wt.%): pig manure (35-45), Casuarina equisetifolia (8-12), peanut shell (8-12), shell powder (10-14), calcium superphosphate (3-6), water (20-30) and endomycorrhizal fungi (EM) fungicide (20-30). The pig manure is subject to dry-wet separation process.    USE - The calcium organic fertilizer is useful for preventing and/or treating peanut blight in coastal regions.    ADVANTAGE - The fertilizer is cost-effective.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) method of preparing the above-mentioned fertilizer, involves (a) subjecting fresh pig manure to dry-wet separation process, drying peanut shell in air, shredding the peanut shell with a shredder, sieving the obtained shell using 0.5 cm sieve, sieving C.equisetifolia using 0.5 cm sieve, and sieving the shell using 1 mm sieve to produce shell powders, (b) mixing the pig manure, C.equisetifolia, peanut shell and shell powder, adding a EM fungicide solution formed by diluting EM fungicide in water to the obtained mixture, and uniformly stirring and mixing the mixture, (c) composting the mixture at 60-65 degrees C for 2-3 days, cooling the obtained compost, stirring the compost for three times by rotting and fermenting processes, and drying the obtained product in air after fermenting respectively for 3-5 days, 11-13 days, 18-20 days and 25-28 days, (d) composting the fermented mixture, controlling moisture of the fermented mixture as 50-60% at the initial stage (initial 18 days) of composting process, controlling moisture of the fermented mixture as not less than 40% after 12-14 days of the composting process, adjusting pH as not greater than 8 after 13-19 days of the composting process by adding calcium superphosphate to the mixture, and (e) performing the composting fermentation for 25-28 days, where the stacked fertilizer produces no unpleasant odor, carbon/nitrogen (C/N) ratio of 10-15 and sprouting index of 70% or more; and (2) method for using the above-mentioned fertilizer, involves uniformly dispersing the fertilizer (200 kg/mu) on surface of the field.