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Transcript of An agricultural definition of soil is "a dynamic natural body on the surface of the earth in which...
Reclamation of salt- affected soils
Munwar Sultana SolangiLady Instructor
Agriculture Training InstituteSakrand
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"
Soil
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 (lime- containing)• 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 saline-
sodic soil
Comparisons of Salt-affected Soils
Parent MaterialIrrigation waterGround waterFlood waterSea waterSalt loving vegetationIndustrial wastage / sewage waterOveruse of chemical Fertilizer
Sources contributi ng salinity
Effects on plant growth
Physical MethodsSub-soiling Deep ploughing Sanding Horizon mixing Profile inversion
Reclamation of Salt- affected soils
Biological methods
- Flooding - Growing of crops - Incorporation of organic matter
Chemical Methods
Gypsum (sodic & saline- sodic)SulfurSulfuric acid Hydrochloric acid
Reclamation of Saline Soils
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.
Crop during Reclamation
Some kind of vegetation should be grown during reclamation, as they help reclamation and also provide some income to farmers. As,RiceSesbaniaSorghumBermuda GrassKallar Grass
Salt Tolerance of cropsTolerant
• Barley• Cotton • Sugar beet• Kallar Grass• Wheat Grass (Tall)• Date palm• Asparagus
Moderately Tolerant
• Wheat • Sorghum• Soybean• Saf flower• Oats• Sweet Clover• Rhodes Grass• Sudan Grass• Beet• Fig• Jujube• Olive• Papaya• Pine apple• Pomegranate
Moderately sensitive• 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• Bean• Sesame• Carrot• okra• Onion• Apple• Apricot• Grapefruit• Lemon• Lime• Mango• Orange• Peach• Pear• Plum• Strawberry
Reclamation of sodic and saline-sodic soil
• 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
Management of salt affected soils
CROP SELECTION
VARIETY SELECTION
IRRIGATION PRACTICES
RIDGE SOWING
PROPER FERTILIZER AND FERTILIZER USE
GREEN MANURING
ORGANIC MANURES ON SODIC-SOILS
SUB-SOILING AND DEEP TILLAGE
MULCHING