These tillage tools are used in the final seedbed preparation. They are also used for post-planting operations to breakup soil crust and remove weeds. In a spike-tooth harrow, the spikes are rigidly mounted on a frame. However, the mounting bars may be spring-loaded (Figure 8.13). The angle of the spikes may be altered to change the aggressiveness, with vertical orientation being the most aggressive. Tine-tooth harrows, as shown in Figure 8.14, use spring tines that create additional action for soil breakup. The tines are closely spaced, about 3.8 to 5 cm apart, compared to spikes in spiketooth harrows. Spring-tooth harrows (Figure 8.15) use round wire teeth made of spring steel. Due to the spring action, these harrows are more suited for stony ground. However, their lack of depth penetration limits their use to less than hard soils. All of these harrows may be used as attachments to other tillage tools such as moldboard plows and disk harrows because of their low draft requirements. Some units may be up to 16 m wide with fold-up frames for road transport.
Figure 8.13 – Different sections used in spike-tooth harrows.
Figure 8.14 – A tine-tooth harrow.
Figure 8.15 – A spring-tooth harrow section.
