1. In some soil types it is desirable to develop a ‘hard pan’ or impermeable layer to stop deep percolation of water below the root zone of the crop.
2. This hard layer is best achieved by using an implement that actually smears the soil during its normal mode of action.
3. The rotovator is the best implement for this operation.
4. High levels of wheelslip from tractors fitted with cage wheels will also give a similar effect.
5. Similarly disc ploughs, offset or tandem discs working in very wet soils can attain a similar effect.