The researchers studied how nitrogen application and herbicide use affect weed management in rice fields. They found that puddled transplanting reduced weed density and improved weed control efficiency compared to unpuddled transplanting. Using butachlor followed by cono-weeding resulted in higher plant growth, tillers per hill, and grain yield compared to other herbicide combinations. Applying nitrogen in specific amounts at different growth stages also increased rice grain yield. Overall, the study showed that proper nitrogen application and herbicide use can significantly improve weed management and rice yield in the field.