The researchers studied how different fertilization methods affect greenhouse gas emissions in a paddy-cowpea rotation system in China. They tested five treatments and found that optimizing fertilization can significantly reduce nitrous oxide emissions by up to 86%. Methane emissions varied depending on the treatment, with some increasing and others decreasing compared to conventional farming methods. The best approach, called slow-controlled optimization fertilization (SCOPT), not only increased crop production but also lowered greenhouse gas emissions. Overall, SCOPT was the most effective in reducing the environmental impact of farming in the tropical region of China.