Effect of spade angle and spading frequency of spading machine on specific soil resistance and pulverization

Abstract

The effect of spade angle and spading frequency on various dependent variables, i.e. specific soil resistance encountered, energy consumed per unit volume of soil moved, weighted mean clod size, soil bulk density, soil cone index and cone index ratio were studied.  The experiments were conducted in soil having 15.7% clay, 53.6% silt, and 30.7% sand.  During experimentation, moisture content of soil was maintained between 13% and 14%.  The spade angles used were A1 (0°), A2 (15°) and A3 (30°).  Four levels of bite lengths viz. 4, 6, 8 and 10 cmat travel speed of 18.47 cms^-1 were selected for the study.  These corresponded to four levels of spading frequencies namely F1 (1.85 cycles s^-1), F2 (2.31 cycles s^-1), F3 (3.08 cycles s^-1) and F4 (4.62 cycles s^-1).  The spading frequency was determined by dividing the travel speed by the bite length.  The dependent variables decreased with increase in spade angle and spading frequency.  However, the cone index ratio increased with increase in spade angle and spading frequency.  Therefore, for maximum pulverization and optimal specific soil resistance and energy consumption, larger spade angle and higher spading frequency were considered to be desirable.