The document discusses aridity, drought, and drought classification. It provides definitions of aridity as a long-term lack of water or moisture caused by wind systems, rain patterns, and temperature. There are three arid zones delineated based on an index: hyper-arid, arid, and semi-arid zones. The arid zone has little farming without irrigation due to lack of available water. The hyper-arid zone has few scattered shrubs and very low rainfall. The semi-arid zone can support rain-fed agriculture. Drought is defined as a prolonged dry period resulting from lack of precipitation. There are three types of drought: hydrological, meteorological, and agricultural droughts which

2.  Name : Muhammad Bilal
 Presentation topic: aridity, Drought and
classification of drought
 Course Title : Agri tunnel farming
 Submitted to : sir Muhammad Saleem Chang
 Institute : Sindh Agriculture university Sub
campus umerkot ( Department of Agronomy)

3. Aridity
• A long term Lake of water , rainfall or
moisture
• Aridity is basically a comparison between
water supply and water need.
• Water supply in general is the amount of
water received from precipitation, while
water need is measured in terms of
evapotranspiration.

5. Causes of aridity
 Wind system
 Rain
 Temperature

6. Three arid zones can be delineated by
this index: namely, Hyper-arid zone Arid
zoneSemi-Arid zone
 Of the total land area of the world, the
hyper-arid zone covers 4.2 percent.
 The arid zone 14.6 percent,
 The semiarid zone 12.2 percent.

7. Arid zone
 is characterized by pastoralism and no farming
except with irrigation.
 Lake of Available water To extent Hindering and
preventing The growth and development of plant
life and animal life
 The native vegetation is low, being comprised of
annual and perennial grasses and other
herbaceous vegetation.

8. Hyper arid zone
 Comprises dryland areas without vegetation,
with the exception of a few scattered shrubs.
 Annual rainfall is low, rarely exceeding 100
millimeters.
 The rains are infrequent and irregular,
sometimes with no rain during long periods of
several years.

9. Semiarid zone
 The semi-arid zone
 can support rain-fed agriculture with more or less
sustained levels of production.
 Native vegetation is represented by a variety of
species, such as grasses and grass-like plants,
half-shrubs, shrubs and trees.
 Annual precipitation varies from 300-600 to 700-
800 millimeters, with summer rains, and from
200-250 to 450-500 millimeters with winter rains.

10. Drought
 Drought is a prolonged dry period in the natural
climate cycle that can occur anywhere in the
world. It is a slow-onset disaster characterized by
the lack of precipitation, resulting in a water
shortage. Drought can have a serious impact on
health, agriculture, economies, energy and the
environment.

11. Classification of drought
Hydrological Drought
 Hydrological drought is associated with the effect
of low rain falls on water level in reservoirs,
rivers and lakes .
 This type of drought are noticed some times after
a metrology drought
 A hydrological drought change in water level
effects ecosystem.

12. Metrological drought
 Is generally defined by comparing the rainfall in a
particular place and at a particular time .
 This happnes when the actual rain fall in an area
is significantly less than the climatological mean
of that area .
 Metrological drought leads to soil moisture and
this always has an effect on crops production

13. Agricultural drought
 Agricultural drought occurs when there is not
enough water for a crop to grow at the particular
time.
 This type of drought does not depend only in the
amount of rainfalls where water is used carelessly
for irrigation and other purpose