Abstract:The study took down slope ridge planting, flat planting, and cross ridge planting as the study object, studied the characteristics of surface runoff, interflow and nitrogen loss under natural rainfall conditions in the yellow soil area, and intended to provide the theoretical basis for predicting and preventing nitrogen loss. The results showed that:The average surface runoff at maize mature stages was 7.96 times and 8.22 times higher than the interflow in 0-20 cm and 20-40 cm soil depths under the conditions of natural rainfall. The surface runoff and nitrogen loss were significantly different under different tillage measures. The surface runoff and nitrogen loss were in order of down slope ridge planting > flat planting > cross ridge planting. The surface runoff of down slope ridge planting was 1.20 times and 2.07 times higher than that of flat and cross ridges planting respectively. Nitrogen loss in down slope ridge planting was 1.35 times and 2.06 times higher than that of flat and cross ridge planting. Under cross ridge planting, the interflow and nitrogen loss of the 0-20 cm and 20-40 cm soil depths were significantly higher, and nitrogen loss in 0-20 cm soil depths was 2.45 times and 1.90 times higher than that of down slope ridge and flat planting respectively, while nitrogen loss in the 20-40 cm soil depths was 2.34 times and 1.79 times higher than that of down slope ridge and flat planting respectively. Surface runoff was the main channel for nitrogen loss. The dissolved nitrogen accounted for 63.84%~72.61% of the total nitrogen loss, and was the main form of nitrogen loss. Nitrate nitrogen accounted for 16.47%~59.17% of the total nitrogen loss, and was the main form of inorganic nitrogen loss. There were significant linear positive correlations between nitrogen loss and runoff, rainfall. Cross ridge planting was an effective way to decrease nitrogen loss under the condition of natural rainfall and reasonable tillage measure can protect water and soil resources and prevent nitrogen loss in the study region.