Preparation method and application method of cotton breeding substrate

The invention discloses a preparation method of cotton breeding substrate, comprising the steps of I, mixing wheat straw powder and boll hull powder, adding water to reach a water content of 55-60%, adding 1.5 parts of EM (effective microorganism) bacteria, mixing well, fermenting to obtain a first fermented material, adding dandelion powder into the first fermented material, and continuing to ferment to obtain a second fermented material; II, mixing 20 parts of pig down, 2 parts of earthworm powder, 3 parts of shrimp shell powder and 2 parts of ladybird powder, disinfecting, and fermenting toobtain a third fermented material; III, mixing well the second fermented material, the third fermented material, 20 parts of sand 200-300 in mesh, 0.08 part of celangulin, 5 parts of plant ash and 6parts of straws 0.5-0.7 in length. The invention also discloses an application method of the cotton breeding substrate. The preparation method and the application method of the cotton breeding substrate have the advantage that