This study provides an overview of soil mechanical conditioning and the development of a low-cost stone-clod separator for a new cultivation system (NCS) of potatoes in Hokkaido. Field tests showed that the soil-crushing performance and the working hours of the developed separator were the same as those of an expensive imported machine. The quantity of clods conveyed to the furrows and the working hours of the developed separator were 5.6 t / ha and 0.45 ha / h, respectively. The NCS had several advantages over the conventional cultivation system, such as significantly (p ≤ 0.01) fewer distorted potatoes and significantly (p ≤ 0.01) fewer stone-clods mixed with potatoes during machine harvesting. The NCS also reduced labor input for potato harvesting by approximately 28 %.