Various types of blades are available for rotary tillers, but the L-shaped blade is the most common. These blades are usually superior to others in heavy trash. They are better for killing weeds and generally cause less soil pulverization.

Penetrating hard soil may be easier with C-shaped blades. They are curved more than L-shaped blades and are recommended for heavy, wet soil, because they have lesser tendency to clog the rotor (see Figures 1 and 2).

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When strip-tilling and planting in one operation, it is sometimes recommended that long blades be used in the row to prepare a seedbed. Shorter blades are used between the rows to kill weeds. The surface is mulched at the same time with less power requirements (see Figures 3 and 4).

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Rotary tillers are also designed for special applications, and they are equipped with various soil-engaging tools, such as chisel tines that penetrate the soil to fracture tractor tracks and to mix the soil into a uniform seedbed. The straight spike points are generally used in previously worked soil or for shallow weed control (see Figure 5).

During shallow weed control, the forward speed can be as high as 12 km/h.

Straight-knife type blades can be used to slice through the soil to aerate and loosen clay soils, eliminate surface compaction, and improve moisture penetration. The primary application for these blades is for lawns, parks, and golf courses.

When a rotary tiller is used for secondary tillage, like breaking clods and tearing weeds, the blades to be used will be thin, flat, straight, and with arrow points for flailing the soil (see Figure 6).

Next month we shall look at the location of the drive. We thank the ARC Agricultural Engineering in South Africa who made the information on rotary tillers available to the readers of ProAgri Zambia.