Fertilizing method for saline-alkali soil dry farming biogas slurry encapsulated biochar

The invention discloses a fertilizing method of saline-alkali soil dry farming biogas slurry encapsulated biochar. Corn straw is prepared into biochar by adopting a pyrolysis method. The biogas slurry is formed by fermenting pig manure and straw, the biogas slurry is obtained through filtering, the biogas slurry is sprayed into biochar particles to be stirred into paste, then air drying treatment is conducted, and after the mass of the paste is constant, the paste is pressed into particles. The prepared biogas slurry encapsulated biochar particles are applied to farmland as a base fertilizer, and a compound fertilizer is applied as an additional fertilizer during crop growth. The method not only reduces the use amount of chemical fertilizer, but also solves the problems that the conventional biogas slurry returning use amount is difficult to determine, organic matters in the biogas slurry are easy to lose, agricultural non-point source pollution is caused and the like. Meanwhile, the biochar is used as a biog