Abstract:Incorporated wheat straw returning can change soil properties, which in turn affects soil erosion resistance. In order to clarify the response of soil erosion resistance after incorporated wheat straw returning to the field, this study took cinnamon soil in the earth-rocky mountain areas of northern China as research object. The orthogonal design table of L9 (34) was used to arrange the treatments with factors of straw length (2, 5, 8 cm), straw returning amount (2 000, 4 000, 8 000 kg/hm2), pure nitrogen application amount (100, 140, 180 kg/hm2), and pure polyphenol application amount (0, 40, 80 kg/hm2) at three gradients. Totally, the study had 10 treatments including a controlled trial. The soil erodibility and critical shear stress were measured by the JET equipment. The results showed that the soil critical shear stress of all returning treatments increased compared with the controlled trial, but the difference was not significant (P>0.05). The effect of nitrogen fertilizer on the soil critical shear stress was significant, and the critical shear stress firstly increased and then decreased with the increase of nitrogen fertilizer amount. The straw length, straw returning amount, nitrogen fertilizer, and polyphenol had significant influence on soil erodibility. The contribution rates of straw returning and polyphenol were 50.61% and 23.84%, with negative and positive effects, respectively. Under the condition of incorporated wheat straw returning to the field, the soil erodibility could be fitted linearly with soil saturated water content and >0.25 mm aggregate content (R2=0.81, P<0.01). The change of critical shear stress could be simulated with the content of water-stable aggregate of >0.25 mm and soil erodibility (R2=0.76, P<0.05). The results maybe helpful to understand the change and mechanism of soil erosion resistance after incorporated straw returning and provide data for soil erosion modeling.