Traditionally, overturning soil by tillage tools is popularly used to improve the crop yield of degenerated grassland in Northern China. This method can effectively change soil physical and chemical properties; but, it dramatically increases the risks of wind and water erosion. Field tests were conducted to evaluate the effectiveness of a root-cutting mechanism which was previously designed for the purposes of cutting the grass (Leymus-chinensis) roots and gashing the soil. This mechanism can penetrate into soil to a depth of 200 mm. Measured parameters included soil moisture content, bulk density, porosity, pH value, organic carbon, total nitrogen and crop yield. Test results also indicated that this mechanism could gash soil and break tangled roots with minimum soil disturbance. The results showed that the soil bulk density was reduced, and the soil porosity increased after the field plots were treated with this mechanism. Comparison of measured results from test and control plots indicated that soil moisture contents, soil bulk densities, and soil porosity were numerically increased, but not statistically significant. Soil organic matter and total nitrogen were significantly increased. Soil pH value was reduced to the level the grass growth needed. Crop yield was increased by 110.52%.