Transcript affected soils - Sindh Chamber of Agriculture

An agricultural definition of soil is "a
dynamic natural body on the surface
of the earth in which plants grow,
composed of mineral and organic
materials and living forms"
Types of soil
Salt- Affected soils
• The soils contain
excessive amounts of
either soluble salts or
exchangeable sodium
or both.
Nature of salt- affected soils
Saline soils:
Soils containing sufficient
amount of soluble salts to
interfere with germination
and growth of most crop
plants are classified as
saline.
Sodic soils
• Soils containing
sufficient
exchangeable
sodium to
adversely affect
their properties
and plant growth.
Saline- sodic soils
Soils containing
both soluble salts
and exchangeable
sodium
Soil Properties
1. Saline (non sodic) soils
• EC > 4 ds/m
• SAR < 15
• pH < 8.5
• "neutral" salts
• often calcareous (limecontaining)
• pH = 8.2 - 8.5
• "white alkali" soils
= white surface crust
2. Saline-Sodic soils
• EC > 4 ds/m
• ESP (SAR) > 15
• pH < 8.5
• controlled by salts and lime
• pH> 8.5
• also called "white alkali“
3. Sodic (non-saline) soils
• EC < 4 ds/m
• ESP (SAR) > 15
• poor physical condition
• pH > 8.5
• high pH disperses organic
matter Þ dark color
• = "black alkali"
• worst soil of the salt-affected
• high dispersion = water-logging
• can result from leaching salinesodic soil
Comparisons of Salt-affected Soils
Parent Material
Irrigation water
Ground water
Flood water
Sea water
Salt loving vegetation
Industrial wastage / sewage water
Overuse of chemical Fertilizer
Effects on plant growth
Sub-soiling
 Deep ploughing
 Sanding
 Horizon mixing
 Profile inversion
Reclamation of saline soil is done by
applying excess water to the soil surface.
The removal of salts may be accomplished
either by continuous ponding of water on
soil surface or by intermittent leaching.
Some kind of vegetation should be grown during
reclamation, as they help reclamation and also
provide some income to farmers. As,
Rice
Sesbania
Sorghum
Bermuda Grass
Kallar Grass
Salt Tolerance of crops
Tolerant
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Barley
Cotton
Sugar beet
Kallar Grass
Wheat Grass (Tall)
Date palm
Asparagus
Moderately Tolerant
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Wheat
Sorghum
Soybean
Saf flower
Oats
Sweet Clover
Rhodes Grass
Sudan Grass
Beet
Fig
Jujube
Olive
Papaya
Pine apple
Pomegranate
Moderately sensitive
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Maize
Millet
Groundnut
Rice
Sugarcane
Sunflower
Barseem
Sesbania
Cabbage
Cauliflower
Corn
Cucumber
Egg plant
Lettuce
Muskmelon
Potato
Pumpkin
Radish
Spinach
Sweet potato
Tomato
Turnip
Water melon
Grape
Sensitive
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Bean
Sesame
Carrot
okra
Onion
Apple
Apricot
Grapefruit
Lemon
Lime
Mango
Orange
Peach
Pear
Plum
Strawberry
• Reclamation of sodic and saline-sodic soil is more difficult, time
consuming and expensive.
• It involves not only leaching a soluble salts but also the
replacement of exchangeable sodium with calcium and the
improvement of physical properties of soil.
• The two most difficult aspects of the reclamation process are
- Provision of source for replacement of sodium with calcium
- Water for leaching