The study looked at how rice roots and soil microbes interact to use nitrogen in the soil. They compared different forms of nitrogen, carbon levels, and gene abundance in the soil around rice roots versus non-rhizosphere soil. They found that the rhizosphere soil had higher dissolved organic carbon but lower nitrogen levels and microbial gene abundance. This suggests that competition for nitrogen in the rhizosphere soil is strong, affecting the growth of soil microbes. When nitrogen is limited, the growth of rhizosphere microbes depends on their ability to compete with rice roots for nitrogen.