It is important for the agricultural administration of Kyushu, a region characterized by high temperature and precipitation, to promote the production of summer and autumn vegetables to achieve regional self-sufficiency. Therefore, fields for the production of summer-autumn cabbage and summer radish in cool areas such as Kuju, Handa and Aso have been developed on sloping lad reclaimed from native grassland. However, since cultivations is performed during the rainy season, soil is markedly eroded, resulting in the gradual degradation of the reclaimed fields. In this study, the onset mechanism of soil erosion in cabbage fields reclaimed from native grasslands was analyzed to develop methods of control. Based on the preventive effect of wild grass residues on soil erosion, the effect of the introduction of a second crop whose residues would be plowed-in was analyzed. It was observed that the use of rye as second crop, to plow stubbles 25 cm in length into soil, along with up-and-down high ridge culture of cabbage, resulted in a 40% reduction of soil loss and increase of yield compared with the conventional method.