WATER ABSORPTION AND TRANSPORT
Plants absorb water from the soil through their root hairs.
The soil water may or may not be available to the plants. On the basis
of availability, can be classified into following types-
1. Holard: It is the total amount of water present in the soil.
2. Chesard: It is the water that is available to the plants.
3 Echard: It is the water that cannot be absorbed by the plants
as it is present in non-available form.
The soil water can be classified into following 5 types -
1. Gravitational Water. It is free water that moves downwards
through the soil due to the force of gravity and reaches at the soil
water table. it becomes beyond the reach of plant roots and is not
easily available to plants.
2. Capillary Water. It is the water that exists between the soil particles
in small capillary pores. It is the water that remains in the soil after the
gravitational water has drained. This water is retained on the soil
particles by the forces of surface tension.this is the main type of water
absorbed by the plants.
, 3. Hygroscopic or imbibed water- the water adsorbed on the
surface of soil particles. The magnitude of this water is also very small
and is available to the plants.
4 Runaway water- the rain water which flow on the surface of the soil
and is not available to the plants.
5. Chemically combined water-combined with the mineral present in
the soil and not available to the plants.
Drought is generally regarded as a dry spell of weather for a
sustained period of time.
Generally two types of drought are recognized-
1. Physical drought- Physical drought may again be divided into
soil drought and atmospheric or climatic drought. The soil
drought occurs when the vegetation absorbs water from the soil
and transpires it through the aerial parts, and if the soil moisture
is not replenished the plants wither away.
Atmospheric drought occurs during hot weather when the
atmospheric air is dry. This enhances the rate of transpiration
many folds than the water absorption through the roots. Of the
two types, soil drought adversely affects the growth of plants.
2. Physiological drought - In The physiological drought, the salt
concentration is increased in the soil water. Though enough
Plants absorb water from the soil through their root hairs.
The soil water may or may not be available to the plants. On the basis
of availability, can be classified into following types-
1. Holard: It is the total amount of water present in the soil.
2. Chesard: It is the water that is available to the plants.
3 Echard: It is the water that cannot be absorbed by the plants
as it is present in non-available form.
The soil water can be classified into following 5 types -
1. Gravitational Water. It is free water that moves downwards
through the soil due to the force of gravity and reaches at the soil
water table. it becomes beyond the reach of plant roots and is not
easily available to plants.
2. Capillary Water. It is the water that exists between the soil particles
in small capillary pores. It is the water that remains in the soil after the
gravitational water has drained. This water is retained on the soil
particles by the forces of surface tension.this is the main type of water
absorbed by the plants.
, 3. Hygroscopic or imbibed water- the water adsorbed on the
surface of soil particles. The magnitude of this water is also very small
and is available to the plants.
4 Runaway water- the rain water which flow on the surface of the soil
and is not available to the plants.
5. Chemically combined water-combined with the mineral present in
the soil and not available to the plants.
Drought is generally regarded as a dry spell of weather for a
sustained period of time.
Generally two types of drought are recognized-
1. Physical drought- Physical drought may again be divided into
soil drought and atmospheric or climatic drought. The soil
drought occurs when the vegetation absorbs water from the soil
and transpires it through the aerial parts, and if the soil moisture
is not replenished the plants wither away.
Atmospheric drought occurs during hot weather when the
atmospheric air is dry. This enhances the rate of transpiration
many folds than the water absorption through the roots. Of the
two types, soil drought adversely affects the growth of plants.
2. Physiological drought - In The physiological drought, the salt
concentration is increased in the soil water. Though enough
