What is "disc harrow"

n. a harrow with a series of disks set on edge at an angle [syn: disk harrow]

A disc harrow is a farm implement that is used to till the soil where crops are to be planted. It is also used to chop up unwanted weeds or crop remainders. It consists of many carbon steel and sometimes the longer lasting boron discs, which have many varying concavities and disc blade sizes and spacing (the choices of the later being determined by the final result required in a given soil type) and which are arranged into two sections ("offset disc harrow") or four sections ("tandem disc harrow"). When viewed from above, the four sections would appear to form an "X" which has been flattened to be wider than it is tall. The discs are also offset so that they are not parallel with the overall direction of the implement. This arrangement ensures that the discs will repeatedly slice any ground to which they are applied, in order to optimize the result. The concavity of the discs as well as their offset angle causes them to loosen and lift the soil that they cut.

A discer is an evolved form of a disc harrow, more suitable to Saskatchewan prairies, where it was developed in the 1940s. It does not leave ridging and it is lighter to pull, so it can be made bigger. After the 1980s their domination started to fade.