The study looked at how adding nitrogen affects enzymes in rice soil. They used special bags to separate soil near the roots (rhizosphere) from regular soil. They found that adding nitrogen increased one enzyme's activity in mature rice soil. Another enzyme's activity changed with the rice's growth stage. The type of soil enzyme activity was influenced by different factors like carbon and nitrogen levels in the soil. The effects of adding nitrogen on the soil's microbial community need to be considered along with plant and soil characteristics.