On the Field Capacity of Flat Plowing by the Two-way Plow of Tiller-type Tractor. M. IImoto. Faculty of Horticulture, Chiba University, Matsudo, Japan. Tech. Bull. Hort. Chiba Univ., No.14, 107〜110, 1966. The use of a tiller-type tractor in a small area of agricultural field is considered to be important, because of its high manoeuvability and field efficiency. In order to study the methods of flat plowing, a two-way plow of tiller-type tractor was used in the field, 483 square meters in area. Four kinds of plowing method, such as the starting from back furrow of field, from boundaries of field, from neighbouring furrow of field and from rounded corners of field were used to compare their field efficiency which is expressed by the ratio of effective field capacity measured in the field to calculated theoretical field capacity. The results are obtained as follows: Among the four kinds of plowing method used in this study, plowing method of the starting from neighbouring furrow of field showed the highest efficiency from view points of travel distance and effective field capacity in the field. It may be said that when the plowing method of the starting from back furrow of field or from boundaries of field is employed, the travel distance will be decreased with plowing by dividing the whole area into small parts.