Method for improving river and lake dredged sediment into green planting soil

The invention discloses a method for improving river and lake dredged sediment into green planting soil, which comprises the following steps: mixing 18-22 parts by mass of raw pig manure, 4-7 parts by mass of sawdust and 1-2 parts by mass of calcium superphosphate to obtain a decomposed precursor; a decomposition microbial inoculum is evenly added into the decomposition precursor, then the decomposition precursor and the decomposition microbial inoculum are transferred into an aeration box or stacked into a windrow type pile for decomposition, decomposed pig manure is obtained, and 0.2-0.3 L of the decomposition microbial inoculum is added into each ton of the decomposition precursor; the river and lake dredged sediment is aired, the decomposed pig manure is added into the aired river and lake dredged sediment, and a first mixed soil body is obtained; and adding a microbial agent into the first mixed soil body to obtain the green planting soil. Various physicochemical indexes of the dredged sediment can be im