Soil Management Handbook - Ministry of Agriculture and Lands

high levels of organic matter promote workability and
tilth.
Many coarse and medium-textured soils are easy to
till over a fairly wide range of moisture conditions,
and maintaining suitable tilth is not difficult. Some
sandy soils, with very low clay and organic matter
content, will not form aggregates at all.
4.2.1 Tillage Implements
There are two main types of tillage implements:
plows and discs, which lift and invert the soil; and
cultivators and harrows, which lift and stir the soil
without inverting it. Some of the more common
implements and tillage practices, and their effects on
the soil, are explained in the following sections. For
more details on tillage implement operation and/or
use, a suggested reference is Fundamentals of
Machine Operation - Tillage, by John Deere.
4.2.2 Rotary Cultivators (Rototiller, Rotovator)
The action of rotary cultivators results in a complete
mixing and pulverizing of the plow layer. See Figure
14.
Because of this, the rotovator is popular as a means of
breaking up and completely incorporating sod, crop
residues, and soil amendments, while preparing a fine
seedbed at the same time. However, the implement
has some serious disadvantages. First, the plow layer
tends to be too pulverized and repeated use over time
Figure 14
Schematic drawing of the action of rotary cultivation
is detrimental to stable soil structure. Second, the
rotovator compacts the subsoil at the depth of
penetration. Avoid slow tractor speeds which result in
excessive pulverizing of the soil. Rotovating appears
to achieve good practical results, but when used
without deeper tillage to break up the tillage pan, the
rototiller can do more harm than good.
Rotovators are most useful for breaking up old sod
prior to plowing, or as a final tillage operation prior to
seeding on sandy or organic soils. Deep rotovating is
not recommended on medium and fine-textured soils
because of the damaging effect the implement has on
the structure of these soils. Following rototilling,
soils must be rolled to make a firm seedbed as poor
seed germination fields are the result of planting into
fluffy, rototilled seedbeds. Rotary cultivators do not
work very well in stony soils.
4.2.3 Spading or Digging Machines
Used as a primary tillage implement, the spading
machine operates on the same principle as a human
powered shovel. In most cases, the implements are
built with multiple bottoms or spades which are
attached to a PTO driven cam shaft. An example of
this type of implement is the "Tortella" which has 6
spades on a cam shaft that is driven by a PTO through
a variable speed gear box. The spade is driven
Soil Management Handbook – Okanagan-Similkameen Valleys 65