Chapter 19 Agricultural and Related Technology
421
Cultivators are used to remove weeds
and open the soil for water. These machines
are a series of hoe-shaped blades pulled
through the ground. See Figure 19-13.
The blades break the crust and allow rain
and irrigation water to enter the soil. They
also cut off and pull out weeds. (A weed is
any out-of-place plant.)
Sprays can be applied to control weeds
and insects. Those controlling weeds are
called herbicides. Insect sprays are called
pesticides. Ground equipment or airplanes
can apply both of these materials. The
equipment has a tank, a pump, and spray
nozzles on a boom. As the plane or ground
applicator crosses the field, a mist of pest
control is applied. See Figure 19-14.
Irrigation Equipment
In parts of the world, rainfall is suffi-
cient to raise crops. Many places, however,
are too dry for successful farming. In some
of these areas, irrigation is used. This is
artificial watering to maintain plant growth.
Irrigation systems can be traced back
to 2100 BC. The Egyptians developed
systems using the water from the Nile to irri-
gate crops. Their systems, similar to all irri-
gation systems, contained these elements:
• A reliable source of water.
• Canals, ditches, or channels to move
the water.
• A way to control and distribute the water.
Figure 19-13. This farmer is cultivating a
row crop (corn). Notice the tank in the front of
the tractor. Fertilizer and an herbicide are being
applied as the plants are being cultivated.
(U.S. Department of Agriculture)
Figure 19-14. A field is being sprayed from the air with chemicals protecting it from weeds and insects.