Abstract
A radish and sweet potato double cropping system is an effective method for reducing growth injury caused by continuous cropping. In addition, this method enables farmers to reduce working hours and production expenses. By using the ridge continuously for radishes in the winter and sweet potato in the summer, farmers can reduce plowing and ridging work before planting sweet potatoes. This paper evaluates economic effects on an upland farm obtained by introducing this cultivation method using a business analysis of a family-run farm in Southern Kyusyu. The results are as follows: (1) Working hours are reduced by 3.3 hours per 10 a compared with the conventional cultivation method. (2) The costs of radish and sweet potato production are reduced by 19,500 yen per 10 a compared with the conventional cultivation method. (3) Farming income increases by 15%.
