The study looked at how different types of fertilizers affect carbon and nitrogen leaching in a paddy soil. They tested four types of fertilizers: no fertilizer, straw return, mineral fertilizers, and pig manure. The results showed that mineral fertilizers increased ammonium nitrogen in the soil, while pig manure increased dissolved organic carbon. Carbon and nitrogen leaching was higher during the vegetative growth stage of rice. Long-term use of mineral fertilizers and pig manure increased nitrogen and carbon content in the soil. The study found a positive correlation between dissolved organic carbon in soil leachate and soil organic carbon, as well as between ammonium nitrogen in soil leachate and total nitrogen in the soil.