1. Match the terms with their definitions.

a) flood irrigation b) furrow irrigation c) sprinkler irrigation d) trickle irrigation	1) It covers a field with water. Dirt mounds called dikes hold the water on the field.
	2) It spreads water in the form of mist over a field. It has an engine and wheels and moves across the field under its own power.
	3) It provides water through plastic tubes. The water trickles out of tiny openings in the tubes into the soil.
	4) It uses narrow ditches to carry water between rows of crops. The water flows through a pipe, foreground, and pours out through openings into the furrows.

2. Find the translation of the following terms and memorize their meaning.

artificial	a well	to pump
a lateral	a water table	a ditch
a network	an aquifer	to penetrate
by gravity	cotton	crop
to lift	to receive	evaporation

3. Read the text to get the gist of it. Answer the following questions.

1. What are the main sources of fresh water?

2. May irrigation water be lost before it reaches the crop?

3. What is transpiration?

Text A

Irrigation is the watering of land by artificial methods. It provides water for plant growth in areas that have long periods of little or no rainfall. The water used for irrigation is taken from lakes, rivers, streams, and wells.

Irrigation is used chiefly in three types of climates: in desert regions (such as Egypt and the Southwestern United States), in regions with seasonal rainfall (such as California and Italy),and in moist regions (such as the Eastern United States and Western Europe). The amount of water needed for farming varies with the type of crop and the climate. For example, rice requires more water than does cotton. Any farmland must receive enough water to allow both for plant growth and for the evaporation of water from the soil.

In some countries, more water is used for irrigation than for any other purpose. For example, irrigation accounts for about 40 per cent of the water used in the United States.

Irrigation requires large supplies of fresh (unsalty) water. The two main sources of fresh water are surface water and ground water.

Irrigation requires a method of transporting water from the supply source to a farm. Most farms obtain surface water by means of a network of canals. A large canal carries the water from the supply source to smaller canals called laterals. The laterals are connected to ditches that take the water to the crops. If a farm lies at a lower elevation than the supply source, the water flows to the canals by gravity. If the farm lies at a higher elevation than the source, the water must be pumped up to the canals.

Ground water is pumped to the surface from wells dug below the water table, the top of an aquifer. If possible, an irrigation well is dug on or near the farm it serves. The pump in the well lifts the water into a ditch or pipe that carries it to the crops. If the well is far from the farm, a system of canals or pipes is needed to bring the water to the crops.

Irrigation water may be lost before it reaches crops. For example, reservoirs lose water through evaporation. The greater the surface area of the reservoir, the more water is lost. The amount of water lost through evaporation can be reduced by building deep reservoirs that have small surface areas.

In regions with porous soils, water may be lost through seepage. Seepage occurs when water leaks from the bottom or sides of reservoirs and irrigation channels. Seepage from reservoirs can be controlled by lining a reservoir with a layer of fine soil that water does not easily penetrate. Engineers try to build reservoirs in places where the soil does not allow much seepage. Seepage from irrigation channels can be prevented by lining the canals or streams with a watertight material, such as asphalt or concrete.

Evaporation of water through the leaves of plants is called transpiration. Plants absorb water through their roots and lose it through transpiration. The transpiration of weeds growing in or near irrigation channels may cause great loss of water. Some loss from transpiration can be avoided by lining the channels with a watertight material to prevent weed growth along the channels.