NOVELTY - Fertilizer comprises 61-96.4 pts. wt. inorganic salt, 5-12 pts. wt. wine dregs, 3-8 pts. wt. rape seed cake, 1.5-5 pts. wt. sodium polyacrylate, 0.5-1.5 pts. wt. EDTA and 0.03-0.12 pts. wt. amine hexanoate. The carbon/nitrogen ratio of wine dregs is adjusted to 25:1, based on ratio of the original wine dregs. The wine dregs is grape wine dregs. The carbon/nitrogen ratio of the rape seed cake is adjusted to 25:1, based on ratio of the original rape seed cake. The rape seed cake is obtained by extracting rape seed oil.    USE - The fertilizer is useful in potato field (claimed).    ADVANTAGE - The fertilizer is resistant to drought (claimed), and environmental friendly; has balanced nutrition; supplies sufficient nutrients to potato field; produces good quality, and high yield products, and smooth texture, and good taste potatoes; increase cold- and disease-resistance capacity in potatoes; solves the problem of weak soil texture in potato field, and difference in water-retention capacity, and weak nutrition supply in potato field, and facilitates coordination of soil nutrient balance. The method utilizes easily available raw materials, has simple operation procedure, produces product with stable quality, produces product whose nutrient elements are completely absorbed by potatoes, and increases the potato production rate reaching up to 20.26-40.12%.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing the fertilizer, comprising (i) mixing 1000 kg original wine dregs with 3.47 kg urea, and adjusting carbon/nitrogen ratio to 25:1, to obtain the wine dregs; (ii) adding urea into wine dregs in 1/3rd the amount, mixing by adding water, until the moisture content reaches 55-60%, uniformly mixing, and filling the materials into a pre-dug pit, and stacking, sealing with soil, fermenting for 130-150 days, taking out, placing in a shady place, and carrying out air-drying by placing in a cool dry place for 30-45 days, until the water content is less than 5%, and sieving through 5 mesh sieve to obtain fermented grape wine; (iii) adding 1000 kg crude oil of rape seed cake with 3.47 kg urea, mixing, and adjusting carbon/nitrogen ratio to 25:1, to obtain the rapeseed cake; (iv) adding rape seed cake and urea in 2/3rd the amount, and mixing by adding water, until the water content reaches 55-60%, uniformly mixing, filling the materials into pre-dug pit, and stacking, sealing with soil, fermenting for 130-150 days, taking out, placing in shady place, drying at 30-45 days, until the water content is less than 5%, and sieving through 5 mm mesh sieve, to obtain fermented rapeseed cake; (v) weighing many other raw materials, and adding fermented wine dregs, fermented rape seed cake and other raw materials, and crushing into powder of particle size 0.10-0.50 mm; (vi) mixing the powder by conveying into a mixer, and uniformly mixing for 25-30 minutes, to obtain a mixture; and (vii) granulating the obtained mixture by conveying into a pelletizer, and performing drying treatment, and cooling to room temperature, to obtain mixture particles, and finally obtaining the product.