Reclamation of salt- affected soils

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 contributing 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