The study looked at how different chemical fertilizers affected the growth of earthworms and the quality of their dung. They found that using 0.75 g·kg-1 of Ca(H2PO4)2, 0.75 g·kg-1 of K2SO4, and 0.50 g·kg-1 of KCl as additives had the best effects on earthworm growth. However, using too much of these additives can harm the earthworms. Over 2.0 g·kg-1 of Ca(H2PO4)2, 2.0 g·kg-1 of K2SO4, and 0.75 g·kg-1 of KCl can reduce the survival and breeding of earthworms. The dung of healthy earthworms can help spinach seeds germinate better and increase their germination rate.