NOVELTY - Method for preparing flue-cured tobacco floating seedling substrate, involves (a) crushing wheat straw in flue-cured chamber, then uniformly mixing wheat straw, water, pig manure or chicken manure, and lime, covering with agricultural plastic film, and stacking for 30 days, (b) drying adhesive soil, sieving through 100 meshes sieve, adding water to the soil, kneading and spreading it on the ground, then evenly mixing the processed wheat straw and wet soil, and stacking for 60 days.    USE - The method is useful for preparing flue-cured tobacco floating seedling substrate (claimed).    ADVANTAGE - The flue-cured tobacco floating seedling substrate raw materials replaces non-renewable peat, prevents disease and pest spreading, is loose and porous, and is beneficial to the growth of root systems in tobacco seedlings, and is high in water and fertilizer keeping capacity.    DETAILED DESCRIPTION - Method for preparing flue-cured tobacco floating seedling substrate, involves (a) crushing wheat straw to less than 3 mm in flue-cured chamber, then uniformly mixing wheat straw powder, water, pig manure or chicken manure, and lime in a mass ratio of 100:60:25-30:1, covering the mixture with agricultural plastic film, stacking for 30 days, and turning the stack during seventh, fifteenth, twentieth, and twenty-fifth day of stacking to obtain processed wheat straw, (b) drying adhesive soil, sieving through 100 meshes sieve, adding water to the soil until the field water holding capacity reaches 65-70%, kneading and spreading it on the ground, then evenly mixing the processed wheat straw and wet soil in the ratio of 1:2.2-2.8, stacking in flue-cured chamber for 60 days, and turning the stack during fifteenth, thirtieth, and fortieth day of stacking to obtain seedling substrate. An INDEPENDENT CLAIM is included for method for preparing flue-cured tobacco floating nutrient liquid, which involves (a) adding and mixing 0.2 g ammonium nitrate, and 0.13 g monopotassium phosphate in one liter of water to prepare nutrient liquid A, (b) adding and mixing 2 g ammonium nitrate, 1.34 g monopotassium phosphate, 0.14 g potassium sulfate, and 0.5 ml of trace element solution in one liter of water to prepare nutrient liquid B, (c) adding and mixing 6 g ammonium nitrate, 4.02 g monopotassium phosphate, 0.42 g potassium sulfate, and 1.5 ml trace element solution in one liter of water to prepare nutrient liquid C, and (d) mixing nutrient liquids A, B, and C, and adding trace elements chosen from 0.5 g borax, 1 g zinc sulfate, 1.5 g ferrous sulfate and 0.25 g copper sulfate to prepare flue-cured tobacco floating seedling substrate.