irrigation to produce more crops or to grow more profitable crops. In some cases, farmers
can choose to grow crops that match the amount of rain that falls in that region naturally.
Figure 21.3: Drip Irrigation uses a series of pipes and tubes to deliver water to the base
of each plant. Because little water is lost to evaporation and runoff, this method uses less
water than sprinklers and trenches. ( 2 )
Insteadofgivingupirrigation, farmerscanuselesswaterbychoosingmoreefficientirrigation
methods, suchasdripirrigation(Figure21.3). Thisirrigationsystemusespipesandtubes
to deliver small amounts of water directly to the soil at the roots of each plant or tree. It
wastes less water than sprinklers and trenches, because almost all of the water goes directly
to the soil and plant roots.
Youmightwonderwhyanyfarmerwouldnotswitchtoefficientirrigationmethods, sincethey
would save so much water. There are two reasons. First, drip irrigation and other efficient
irrigation methods cost more than trenches and sprinklers. Second, in some countries, such
as the United States, the government pays for much of the cost of the water that is used for
agriculture. Because, farmers do not have to pay the full price of the water they use, they
do not have any financial reason orincentiveto use less water.
Aquaculture
Aquaculture is the name for the type of farming you might do if you were raising fish,
shellfish, algae or aquatic plants (Figure21.4). This is a farming practice where plants and
animals that live in water are raised. As the supplies of fish from lakes, rivers, and the oceans
dwindle, people are getting more fish from aquaculture. Raising fish instead of hunting for
them is a different way of increasing our food resources. The next time you pass the fish
display in the grocery store, look for labels for “farm raised” fish. These fish would have
been raised in an aquaculture setting.