Studies on the Pulling Force of Root Vegetables (I)

Measuring Method of the Pulling Force

Abstract

Effective factors on the vertical force for pulling (pulling force), which is equivalent to the maximum available frictional resistance for pulling root vegetables, were investigated.
For measurements of the pulling sorce, a precise force gauge was developed (Fig. 1), From the results of measurements, some rules for the effects of the characteristics of root vegetables and the conditions of soils on the pulling force were clarified (Fig. 2, Table 1, 2, 4).
The pulling force (F) was closely related to the surface area of main roots in soil (S), and the relation between F and S was given approximatly by a linear formula F=aS+b.
The coefficient a=(dF/dS) in this formula was determined by the kind of root vegetables and the condition of soils. This coefficient a was varied from 0.015 to 0.038 (with correspond to those factors) in this experiment (Fig. 3, 4).
The effects of the number of lateral roots and the size of small root on the pulling force were negligible (Fig. 5, 6).