The invention relates to a soil improvement technology and an environment protection technology and particularly discloses a
biochar mixing type protected horticultural vegetable
field soil heavy
metal passivant and a preparation method thereof. The soil heavy
metal passivant comprises the following components in percentage by weight: 50 to 60 percent of
biochar, 5 to 10 percent of medical stone
powder, 5 to 10 percent of diatomite
powder, 10 to 20 percent of lignite and 10 to 20 percent of
coal ash. The preparation method for the soil heavy
metal passivant comprises the following steps of: mixing the medical stone
powder which is screened by an 80-mesh
sieve, the diatomite powder which is screened by an 80-mesh
sieve, the lignite, and the
coal ash which is screened by an 80-mesh
sieve, uniformly stirring, mixing with
biochar which is screened by a 20-mesh sieve, fully stirring, and mixing uniformly to prepare the soil heavy metal passivant. The soil heavy metal passivant is easy to prepare; and the effects of passivating the protected horticultural vegetable
field soil heavy metal, and reducing the content of recyclable heavy metal of
plant in soil can be achieved under the synergistic effects of all components.