chapter 7: Irrigation Flashcards
Historically, civilizations have been dependent on
development of irrigated agriculture
Historically, civilizations have been dependent on development of irrigated agriculture to provide
agrarian basis of a society & to augment the security of people.
Archaeological investigation has identified evidence of irrigation in Mesopotamia, Ancient Egypt & Ancient Persia as far back as the
6th millennium BCE (Before Christ Era).
In the Zana valley of the Andes Mountain in Peru, archaeologists found remains of three irrigation canals referred to the
4th millennium BC, the 3rd Millennium BC & the 9th century CE (Christ Era)
In the Zana valley of the Andes Mountain in Peru, archaeologists found remains of three irrigation canals referred to the 4th millennium BC, the 3rd Millennium BC & the 9th century CE (Christ Era). These canals are
the earliest record of irrigation in the new world.
The Indus valley civilization in Pakistan & North India (from
2600 BC)
The Indus valley civilization in Pakistan & North India (from 2600 BC) also had
an early canal irrigation system
The Indus valley civilization in Pakistan & North India (from 2600 BC) also had an early canal irrigation system. Large scale agriculture was used for the purpose of
irrigation
The Indus valley civilization in Pakistan & North India (from 2600 BC) also had an early canal irrigation system. Large scale agriculture was used for the purpose of irrigation. …………………….. and ……………………… were developed
Sophisticated irrigation & storage systems
The Indus valley civilization in Pakistan & North India (from 2600 BC) also had an early canal irrigation system. Large scale agriculture was used for the purpose of irrigation. Sophisticated irrigation & storage systems were developed, including
the reservoirs built at Girnar in 3000 BC.
There is evidence of ancient Egyptian Pharaoh Amenemhet-III (about ………………….)
1800 BC
There is evidence of ancient Egyptian Pharaoh Amenemhet-III (about 1800 BC) using
the natural lake of the Faiyum Oasis as a reservoir to store surpluses of water for use during the dry seasons.
The Qanats, developed in ancient Persia in about
800 BC
The Qanats, developed in ancient Persia in about 800 BC, are among the
oldest known irrigation methods still in use today
The Qanats, developed in ancient Persia in about 800 BC, are among the oldest known irrigation methods still in use today. The system comprises a network of
vertical wells & gently sloping tunnels driven into the sides of cliffs & steep hills to tap ground water
The irrigation works of ancient Sri Lanka, the earliest dating from about
300 BC
The irrigation works of ancient Sri Lanka, the earliest dating from about 300 BC, were one of the
most complex irrigation systems of the ancient world
The irrigation works of ancient Sri Lanka, the earliest dating from about 300 BC, were one of the most complex irrigation systems of the ancient world. In addition to
underground canals
The irrigation works of ancient Sri Lanka, the earliest dating from about 300 BC, were one of the most complex irrigation systems of the ancient world. In addition to underground canals, the Sinhalese were the first to build
completely artificial reservoirs to store water
The irrigation works of ancient Sri Lanka, the earliest dating from about 300 BC, were one of the most complex irrigation systems of the ancient world. In addition to underground canals, the Sinhalese were the first to build completely artificial reservoirs to store water. The system was extensively
restored & further extended later (1153-1186 CE).
In the Szechwan region ancient China the Dujiangyan Irrigation System was built in
250 BC
In the Szechwan region ancient China the Dujiangyan Irrigation System was built in 250 BC to
irrigate a large area & it still supplies water today
In Korea, the world‟s first water gauge was discovered in
1441 CE
In the Americas, extensive irrigation systems were created by
numerous groups in prehistoric times
In the Americas, extensive irrigation systems were created by numerous groups in prehistoric times. One example is seen near the Santa Cruz River in Tucson, Arizona. They have located a
a village site dating from 4000 years ago
In the Americas, extensive irrigation systems were created by numerous groups in prehistoric times. One example is seen near the Santa Cruz River in Tucson, Arizona. They have located a village site dating from 4000 years ago. The flood plain of the Santa Cruz River was
extensively farmed during the early agricultural period, circa 1200 BC to AD 150.
The Great Dam of Ma’rib certainly dates back to about
the 8th century BC
The Great Dam of Ma’rib certainly dates back to about the 8th century BC and is considered
the oldest known dam in the world
The Great Dam of Ma’rib certainly dates back to about the 8th century BC and is considered the oldest known dam in the world, being counted as one of the most wonderful feats of
of engineering in the ancient world
The medieval Arab geographer Yaqut Al-Ḥamawi describes it thus
It is between
three mountains
The medieval Arab geographer Yaqut Al-Ḥamawi describes it thus:
It is between three mountains, and the flood waters all flow to
the one location
The medieval Arab geographer Yaqut Al-Ḥamawi describes it thus:
It is between three mountains, and the flood waters all flow to the one location, and because of that the water only discharges in
one direction
The medieval Arab geographer Yaqut Al-Ḥamawi describes it thus:
It is between three mountains, and the flood waters all flow to the one location, and because of that the water only discharges in one direction; and the ancients blocked that place with
hard rocks and lead
The medieval Arab geographer Yaqut Al-Ḥamawi describes it thus:
It is between three mountains, and the flood waters all flow to the one location, and because of that the water only discharges in one direction; and the ancients blocked that place with hard rocks and lead. The water from ……………….. gathers there as well as…………………
springs
floodwater
The medieval Arab geographer Yaqut Al-Ḥamawi describes it thus:
It is between three mountains, and the flood waters all flow to the one location, and because of that the water only discharges in one direction; and the ancients blocked that place with hard rocks and lead. The water from springs gathers there as well as floodwater, collecting behind
the dam like a sea
The medieval Arab geographer Yaqut Al-Ḥamawi describes it thus:
It is between three mountains, and the flood waters all flow to the one location, and because of that the water only discharges in one direction; and the ancients blocked that place with hard rocks and lead. The water from springs gathers there as well as floodwater, collecting behind the dam like a sea. Whenever they wanted to, they could…………………… from it
irrigate their crops
The medieval Arab geographer Yaqut Al-Ḥamawi describes it thus:
It is between three mountains, and the flood waters all flow to the one location, and because of that the water only discharges in one direction; and the ancients blocked that place with hard rocks and lead. The water from springs gathers there as well as floodwater, collecting behind the dam like a sea. Whenever they wanted to, they could irrigate their crops from it, by just letting out however much water they needed from
sluice gates
The medieval Arab geographer Yaqut Al-Ḥamawi describes it thus:
It is between three mountains, and the flood waters all flow to the one location, and because of that the water only discharges in one direction; and the ancients blocked that place with hard rocks and lead. The water from springs gathers there as well as floodwater, collecting behind the dam like a sea. Whenever they wanted to, they could irrigate their crops from it, by just letting out however much water they needed from sluice gates; once they had used enough they would
close the gates again as they pleased.
Irrigation is defined as
Artificially supplying & systematically dividing of water for agriculture in order to obtain higher or qualitatively better production
Successful farmers have used different methods to apply water to their crops. This artificial addition of water is
called irrigation
This artificial addition of water is called irrigation. Irrigation is essentially the
artificial application of water
This artificial addition of water is called irrigation. Irrigation is essentially the artificial application of water to overcome
deficiencies in rainfall for growing crops
In traditional agriculture, irrigation was recognized for its
protective role of insurance against the variations of rainfall
Importance of irrigation: in the next 35 to 45 years world food production will need to
double to meet the demands of increased population
Without irrigation, farming is
very limited
Without irrigation, farming is very limited & if the rainfall decreases to less than ………….. , agriculture becomes ……………………………
30cm, agriculture becomes impossible without irrigation
Benefits of irrigation:
- It increases crop yield. It protects from famine. Ultimately it helps in economic development.
- Irrigation water improves water conditions in the soil, increases the water content of plant fibers, dissolves nutrients & makes them available to plants.
- Irrigation affects temperature conditions by regulating the temperature of the surface layer of the soil & the ground layer of the air
- It controls growth & development of plants & improvement of the quality of the harvest.
Irrigation systems are often designed to
maximize efficiencies & minimize labour & capital requirements
There are three broad classes of irrigation system:
- Pressurized distribution. 2. Gravity flow distribution. 3. Drainage flow distribution.
- Pressurized distribution: The pressurized systems include
sprinkler, trickle, in which water is conveyed to & distributed over the fields through pressurized pipe networks.
- Gravity flow distribution:
This system conveys & distributes water at the field level by a free surface, overland flow regime
- Drainage flow distribution
Irrigation by control of the drainage system sub irrigation is not so common but is interesting.
- Drainage flow distribution: Irrigation by control of the drainage system sub irrigation is not so common but is interesting. Relatively large volumes of applied irrigation water percolate through
the root zone
- Drainage flow distribution: Irrigation by control of the drainage system sub irrigation is not so common but is interesting. Relatively large volumes of applied irrigation water percolate through the root zone & become
a drainage or ground water flow
- Drainage flow distribution: Irrigation by control of the drainage system sub irrigation is not so common but is interesting. Relatively large volumes of applied irrigation water percolate through the root zone & become a drainage or ground water flow. By controlling
the flow at critical points
- Drainage flow distribution: Irrigation by control of the drainage system sub irrigation is not so common but is interesting. Relatively large volumes of applied irrigation water percolate through the root zone & become a drainage or ground water flow. By controlling the flow at critical points, it is possible to raise the level of the ground water to
within reach of the crop roots
To supply water to the entire field uniformly so that each plant would get
sufficient amount of water
To supply water to the entire field uniformly so that each plant would get sufficient amount of water, there are various types of irrigation techniques that differ in
how the water obtained from the source is distributed within the field
To supply water to the entire field uniformly so that each plant would get sufficient amount of water, there are various types of irrigation techniques that differ in how the water obtained from the source is distributed within the field. These are:
- surface irrigation
- ditch irrigation
- localized irrigation
- overhead irrigation
- sub irrigation
- manual irrigation
. Surface Irrigation:
In this irrigation system water moves over & across the land by simple gravity flow in order to wet it & to infiltrate into the soil.
Surface Irrigation: In this irrigation system water moves over & across the land by simple gravity flow in order to wet it & to infiltrate into the soil. It is often called
flood irrigation
Surface Irrigation: In this irrigation system water moves over & across the land by simple gravity flow in order to wet it & to infiltrate into the soil. It is often called flood irrigation when the irrigation results in
flooding or near flooding of the cultivated land.
- Ditch Irrigation:
This is the simplest & oldest irrigation system & still common in many parts of the world
Ditch Irrigation: This is the simplest & oldest irrigation system & still common in many parts of the world. The only technology essential is the manpower or machines to
dig ditches
Ditch Irrigation: This is the simplest & oldest irrigation system & still common in many parts of the world. The only technology essential is the manpower or machines to dig ditches or
furrows between the rows of plants
Ditch Irrigation: This is the simplest & oldest irrigation system & still common in many parts of the world. The only technology essential is the manpower or machines to dig ditches or furrows between the rows of plants. Water is added to the ditches by means of
gravity flow, pumps & siphons
. Localized Irrigation
It is a system where water is distributed under low pressure through a piped network, in a pre-determined pattern, & applied as a small discharge.
Drip Irrigation: this is also known as
as trickle irrigation
Drip Irrigation: This is also known as trickle irrigation.
Water is delivered at or near the root zone of plants; drop by drop. This method can be the most water efficient method of irrigation.
Overhead Irrigation:
This is the artificial application of water to crops from above.
Overhead Irrigation: This is the artificial application of water to crops from above. Central pivot systems, which are in wide use in areas of
flat terrain
Overhead Irrigation: This is the artificial application of water to crops from above. Central pivot systems, which are in wide use in areas of flat terrain, have sprinklers spaced along very long
aluminum or steel pipes
Overhead Irrigation: This is the artificial application of water to crops from above. Central pivot systems, which are in wide use in areas of flat terrain, have sprinklers spaced along very long aluminum or steel pipes that extend in ………… directions from …………………………
two directions from a central supply point
Overhead Irrigation: This is the artificial application of water to crops from above. Central pivot systems, which are in wide use in areas of flat terrain, have sprinklers spaced along very long aluminum or steel pipes that extend in two directions from a central supply point. ………………………. are another very common overhead irrigation system.
Sprinkler systems
Overhead Irrigation: This is the artificial application of water to crops from above. Central pivot systems, which are in wide use in areas of flat terrain, have sprinklers spaced along very long aluminum or steel pipes that extend in two directions from a central supply point. Sprinkler systems are another very common overhead irrigation system. In these systems,
water is piped to a point within the area to be irrigated.
Sub-Irrigation: This is also called as
seepage irrigation
Sub-Irrigation: This is also called as seepage irrigation used for
many years
Sub-Irrigation: This is also called as seepage irrigation used for many years in the fields
where water table is high
Sub-Irrigation: This is also called as seepage irrigation used for many years in the fields where water table is high. This method artificially ………………the water table by
raises
allowing the soil to be moistened from below the plants‟ root zone
Manual Irrigation
This system has low requirements for infrastructure & technical equipment but needs high labour inputs by using buckets or watering cans.
According to the different sources of irrigation there are two major divisions found. These are:
- flow irrigation
- lift irrigation
Flow Irrigation:
The water of a reservoir or tank usually remains at a higher level & when a channel is connected to it, water automatically flows down the channel which fulfills the purpose of a canal for irrigation.
Flow Irrigation: The water of a reservoir or tank usually remains at a higher level & when a channel is connected to it, water automatically flows down the channel which fulfills the purpose of a canal for irrigation. In this case water level remains
higher than the fields
Flow Irrigation: The water of a reservoir or tank usually remains at a higher level & when a channel is connected to it, water automatically flows down the channel which fulfills the purpose of a canal for irrigation. In this case water level remains higher than the fields. Such irrigation is known as
as the flow irrigation
Lift Irrigation
Where the fields lie at a higher level & the canals or tanks lie at a lower level, it becomes essential to lift the water by pump etc. to irrigate land.
Lift Irrigation: Where the fields lie at a higher level & the canals or tanks lie at a lower level, it becomes essential to lift the water by pump etc. to irrigate land. Water is lifted from
tanks, wells & tube wells
Lift Irrigation: Where the fields lie at a higher level & the canals or tanks lie at a lower level, it becomes essential to lift the water by pump etc. to irrigate land. Water is lifted from tanks, wells & tube wells by ……….. for ………….. through
pumps for irrigation through channels
Where the fields lie at a higher level & the canals or tanks lie at a lower level, it becomes essential to lift the water by pump etc. to irrigate land. Water is lifted from tanks, wells & tube wells by pumps for irrigation through channels. This method of irrigation is known as the
lift irrigation.
