Soil Management Handbook - Ministry of Agriculture and Lands

Figure 19
Schematic drawing of the effect of plowing on soils
bottom. It is possible to hitch the plow so that the
tractor wheel remains on the unplowed land instead of
in the furrow. If soils are too dry, plowing may result
in the formation of larger clods which will take longer
to break down.
Repeated plowing to the same depth may form a
compacted layer (a plow-sole or plow-pan) which can
become a severe impediment to air and water
movement and root penetration. To minimize the
formation of a plow-pan, it is recommended that
plowing depth be varied. An existing plow-pan may
be broken up by deep tillage with a chisel plow or a
subsoiler.
4.2.8 Harrows
Harrows are either rigid or flexible tines which are
simply dragged across the soil surface, stirring it and
breaking down larger clods. Harrowing may be useful
in preparing a seedbed, or to incorporate certain
pesticides to a shallow depth, to break up straw and
spread it more evenly over the field, or to scarify
pastures and break up and spread manure on pastures.
Repeated harrowing has the effect of pulverizing the
surface and compacting the plow layer.
4.2.9 Aerator
Aerators have been commonly used in the turf
industry for many years, however, more recently they
have been used in the production of crops such as
forage grass. Aerators are designed to break through
surface crusts or layers of organic residue and provide
a channel to allow air exchange within the surface soil
layers. These aeration channels also provide inlets for
rainfall and nutrients. Aerators relieve surface
compaction and will improve the health of a forage
stand.
Turf type aerators come in many forms, the most
common being the hollow tine. Aerators with angled
rolling tines, such as the "Aer-way" may be most
appropriate for use in forage grass production. The
tines are ground driven and can be angled to provide
variable levels of surface disturbance. This type of
aerator can also be used on cultivated land to roughen
the surface and lightly incorporate crop residue or
manure.
4.2.10 Packers
On some soils, a fine seedbed cannot be achieved
conveniently with tillage implements, and it may be
useful to pack the soil after seeding. Packers are
useful for this purpose mainly on loose, sandy soils,
but may be useful on some medium-textured soils.
The "Cultipacker", and other dual-purpose
implements, combines some form of cultivator with
packing wheels. These are well-suited to some soils
and are useful as the final tillage operation prior to
seeding.
68 Soil Management Handbook – Okanagan-Similkameen Valleys