Soil Management Handbook - Ministry of Agriculture and Lands

Figure 17
Schematic drawing comparing the effect of shovel and chisel cultivation on soils
It is important to adjust the angle at which the disc
moves against the soil; too small an angle will tend to
pack rather than loosen the soil.
4.2.7 Plows
The mouldboard plow is designed to lift the soil mass
and throw it sideways so that most of the original
surface soil is inverted and buried under soil from the
bottom of the plow layer. See Figure 19.
Plowing is an effective method of restoring good tilth
to a soil in which the surface structure has broken
Figure 18
Schematic drawing of the action of disc implements
down, while the soil below the surface has developed
a granular structure through the action of plant roots.
The plow is quite useful for burying sod or a heavy
growth of weeds or crop residues.
Plowing when soils are at the right moisture content is
most important. If soils are too wet, the plow will turn
over a solid mass of soil which has been compressed
and compacted by shearing forces of the plow itself.
In addition to this, the bottom of the furrow will also
be compressed and the pores sealed off by the
smearing action of the tractor wheel and the plow
Soil Management Handbook – Okanagan-Similkameen Valleys 67