The study looked at different levels of fertilizer use in rice-wheat rotation in Chengdu Plain to see how much nitrogen and phosphorus were lost through surface runoff. They found that the loss of nitrogen and phosphorus varied depending on the type of fertilization used. In conventional treatment, nitrogen loss was 0.047% and phosphorus loss was 0.018%. Optimize fertilization treatment had nitrogen loss of 0.042% and phosphorus loss of 0.021%. Nitrogen increasing treatment had nitrogen loss of 0.034% and phosphorus loss of 0.026%. Phosphorus increasing treatment had nitrogen loss of 0.015% and phosphorus loss of 0.040%. Conservation tillage had nitrogen loss of 0.018% and phosphorus loss of 0.017%.