NOVELTY - Additive is prepared using 20-25 pts. wt. straw, 14-16 pts. wt. zeolite powder, 1-2 pts. wt. clay, 1-2 pts. wt. amidinothiourea, 1-2 pts. wt. betaine, 1-4 pts. wt. soluble chitosan, 1.4-2.8 pts. wt. fulvic acid, 20-30 pts. wt. pig manure, 4-8 pts. wt. rapeseed cake powder, 1-2 pts. wt. corn flour, 1-2 pts. wt. polyacrylamide, 0.5-1 pt. wt. rhizoma arisaematis, 1-2 pts. wt. radix sophorae flavescentis, 1-2 pts. wt. Perilla stem and 1-2 pts. wt. castor root.    USE - Additive used in sustained-release Eucalyptus fertilizer (claimed).    ADVANTAGE - The additive eliminates heavy metals and cyanides and replaces with beneficial metal ions.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for method for preparing additive which involves (a) sun drying straw and reducing moisture content to less than 20%, charring sun dried straw by carrying out pyrolysis process at 400-500 degrees C, cooling down, grinding and sieving over 1 mm sieve to obtain less than 1 mm biocharcoal, (b) mixing obtained biocharcoal with zeolite powder under stirring condition, washing the obtained mixture with water to remove surface impurities, adding hydrochloric acid solution at a concentration of 5-8%, where the mixture and hydrochloric acid solution are added in the mass ratio of 1:2-3, soaking the mixture at room temperature for 15-18 hours, carrying out solid-liquid separation, drying, sterilizing obtained powder under UV radiation for 10-12 hours to obtain modified material, (c) dissolving betaine in suitable quantity of water, spraying obtained betaine solution over modified materials obtained in step (b) and drying to obtain mixed material, (d) mixing and extracting rhizoma arisaematis, radix sophorae flavescentis, Perilla stem and castor root to obtain medicinal filtrate and storing medicinal residue, mixing chitosan with suitable quantity of water to obtain chitosan solution, combining obtained chitosan solution with medicinal filtrate and polyacrylamide to obtain mixed solution, centrifuging mixed solution at 100-200 revolutions/minute for 10-20 minutes to obtain sterilizing solution, and (e) mixing medicinal residues obtained in step (d) with fulvic acid, rapeseed cake powder, corn flour and pig manure, drying to obtain manure powder, mixing obtained manure powder with modified material obtained in step (b), sterilizing solution obtained in step (d) and remaining raw materials.