Question

Organic wastes and earthworm are added to basic salts

Answer 1

because they are acidic to neutralize the salt

Answer 2

Vermicomposting is the method used to prepare organic compost with the help of earthworms and organic waste. Earthworm's excreta is also helpful in formation of the compost and using Earthworms in the compost helps to speed up the process. But the thing here is that both Earthworms and organic waste makes the compost slightly acidic that is why basic salt is added to that compost in order to make it neutral or less acidic.