Two different shapes of knives (L and Y-shaped) for the rotary slasher with 300 knife cutting angle at three cutting speeds (1830, 2066 and 2044 rpm) were used to indicate their effects on the power consumption for pulverizing sweet potato vine which passed through the sieve (< 28 mm2). The results indicated that all the treatments were significant at p 0.01 significance level for the power consumption on sweet potato vine pulverizing. The best result was recorded from L-shaped knife with a power consumption of 52.12 Watts for sweet potato vine pulverization. Meanwhile, the best result was for the mower speed at 1830 rpm with the lowest power consumption of 61.23 Watts. The best performance for interaction between knife shapes and the cutting speeds was achieved by the L-shaped knife at 1830 rpm with lowest power consumption of 50.23 Watts at p 0.01.

A study was conducted to test the effects of three different speeds of 1830, 2066 and 2440 rpm of a mower knife with serrated edges and two different feeding angles of 45° and 90° on the pulverization of sweet potato vines. The results indicated that all the treatments were significant at 99% significance level for the pulverized percentage of sweet potato vines remaining on the sieve. The best result was for the 45° feeding angle with lowest vine pulverized percentage of 47.20%. The second speed of 2066 rpm had the finest vine pulverized percentage of 57.47%. The best performance for overlapping effect between feeding angle and speed of mower was achieved by the 45° feeding angle and a mower speed of 1830 rpm resulting in an average percentage of 44.45 % of pulverized vines.

The effects of a rotary slasher with two different shapes of knives (L and Y-shaped) at three cutting speeds (1830, 2066 and 2044 rpm) were studied on percentage of pulverization of sweet potato vine passing through the sieve (< 28 mm2). The results showed that all the treatments were significant at p 0.05 and p 0.01 significance level. The best result was by Y-shaped knife with highest vine pulverized percentage of 82.76 % and a mower speed of 2440 rpm had the finest vine pulverized percentage of 90.48 %. The best performance for interaction effects between knife shapes and speeds of mower was achieved by the Y-shaped knife and a mower speed of 2440 rpm resulting in an average percentage of 92.62 % of pulverized vine.

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