Agriculture Reference
In-Depth Information
Figure
5.7.
Potato planter pulled by a tractor. (Courtesy of Kitty O'Neil.)
containing what are referred to as eyes. The eyes are growing points that are visible on
the surface of the tuber. A section of the tuber, of approximately 55 g, containing the
eye shown in Figure 5.5 is treated to prevent fungus infections and then stored for a
week to allow the cut side to form a hardened, protective layer.
A mechanical potato planter, shown in Figure 5.7, plants these seed pieces, which
are placed in the hopper, the upper part of the planter. The lower part of the planter
opens a furrow, allows the seed pieces to drop into the furrow, which is then
covered with soil and packed. During planting, the seed pieces may also be sprayed
to prevent insect damage.
Plants may also be propagated from the tops or vines, and this is a particularly preva-
lent method of reproduction of sweet potatoes, yam, and boniato in tropical countries.
Reproduction using vines is done in two ways. A portion of a vine can be buried in
the soil, and the buried portion will develop roots that subsequently produce tubers. Alter-
nately cuttings of the vines may be taken and planted in a new seedbed.
Root crops are susceptible to infection by numerous disease organisms including
viruses. Planting materials, both seed potatoes and vines, may harbor these organisms.
Thus, a number of methods are used to control diseases in potatoes. The most important
is to use disease-free planting materials, which can be obtained from commercial seed
produces. Unfortunately, much of the world lacks the development of a seed industry,
which means that farmers do not have access to disease-free planting materials. This in
turn results in decreased yields worldwide.
Other methods of disease control are crop rotation, between potatoes and other
crops, and soil fumigation. In addition control of pests and insects that transmit
disease organisms is also important.
All root crops grow best in soil that farmers describe as being light. That is, it is
easy to work and does not have high clay content. These soils would have a sandy or