The study looked at how different fertilizers affect the way soil microbes use carbon in rice fields in southern China. They used a special method to measure this. Results showed that soils with organic and rice straw fertilizers had more active microbes than those without. Microbes in the roots of rice plants used carbon differently than those in other parts of the soil. Soils with organic fertilizers had better ability to use external carbon sources. Microbes preferred carboxylic acids over amino acids and carbohydrates. Overall, organic fertilizers improved soil microbial activity and carbon use in rice fields.