Preparation method of modified cotton stalk carbon-based urea fertilizer

The invention discloses a preparation method of a modified cotton stalk charcoal-based urea fertilizer, which comprises the following steps: crushing cotton stalks, sieving with a sieve, loading into a crucible, sealing, and pyrolyzing at constant temperature to obtain cotton stalk charcoal; wood vinegar is diluted, cotton stalk charcoal is added and stirred, the cotton stalk charcoal is fully soaked in the wood vinegar, the cotton stalk charcoal is filtered out and dried in a drying box, and modified charcoal is prepared; respectively putting the cotton stalk charcoal and the modified charcoal into different beakers, adding pure water, heating, boiling, filtering, and detecting the pH value of filtrate; crushing urea particles, fully and uniformly mixing the crushed urea particles with the modified carbon through a screen, adding a pre-gelatinized starch binder, and uniformly stirring to prepare a fertilizer mixture; and adding water into the fertilizer mixture, fully and uniformly stirring, pouring into a p