SOIL PREPARATION

Originally, the finger plough contained three blades (Figure 7.7). Practical experience has, however, shown that the middle blade is unnecessary, and even detrimental in some cases. Three blades on a finger plough result in too small a gap between the blades and consequently large clods are pushed to the surface during ploughing. This plough was consequently adapted to contain only two blades (Figure 7.8). On a two-blade finger plough the space between blades should be at least 40 cm to allow the loosened soil to tumble through the gap between the fingers (Saayman, 2018). A slightly wider gap (55 cm) is preferred by Nolte (2019).

FIGURE 7.8: The adapted finger plough equipped with only two fingers that are slightly wider spaced than on the original plough. (Photo: J.E. Hoffman, Stellenbosch University).

An implement that deserves mentioning, although it did not withstand the test of time, is the soil mixer (Figure 7.9). The soil mix implement was specifically developed to work between vine rows in existing vineyards, but it was also used for soil preparation before planting. A rotating cylinder of 800 mm diameter equipped with tungsten tines that give it extra reach, creates the loosening action of the implement. Bringing poor subsoil to the soil surface and destroying soil structure were the main problems of the soil mixer (Figures 7.10 and & 7.11).

116 | CHOICE OF IMPLEMENT FOR SOIL PREPARATION