IN THE NAME OF ALLAH, THE COMPASSIONATE, THE MERCIFUL

Reclamation of Salt Affected Soils

by

Rizwan Zahoor

2004-ag-1537

B.Sc. (Hons) Agri.

Agronomy 7th

Objectives of Reclamation:

1. To increase crop yield per unit area

2. To increase WUE

3. To improve farmers’ living standard

Methods of Land Reclamation:

1: Physical Methods

– Sub soiling– Deep ploughing– Sanding– Horizon mixing– Profile inversion

2: Biological Methods

Growing of crops on problem soils and/or their

incorporation at the stage of maximum biomass

productivity.

3:Chemical Methods

It includes the application of

– Gypsum

– Sulphur

– Sulphuric acid

– Hydrochloric acid etc

Prerequisites for Land Reclamation:

• Good surface drainage

• Leveled soils

• Availability good quality water

• Chemical amendments

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.

Reclamation Requirement:

It is amount of water required for reclamation, usually

depends upon

– Salts concentration

– Soil texture

– Soil structure

– Trenching

Reclamation of sodic and saline-sodic soil:

Reclamation of sodic and saline-sodic soil is more difficult,

time consuming and expensive than that of saline soil. 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

Sources of calcium for replacing exchangeable sodium:

– Irrigation water

– Gypsum and lime present in soil

– Chemical and biological amendments

– High-salt water

Replacing exchangeable sodium:

CaCO3 is insoluble in water. However, the presence of lime

is important in sodic and saline-sodic soil, if it is treated with

acids or sulphur, it provides calcium.

when vegetation is established, CO2 released and converts

the CaCO3 into relatively soluble Ca(HCO3)2.

Crop During Reclamation:

Some kind of vegetation should be grown during

reclamation, as they help reclamation and also provide

some income to farmers.

Growth of crop helps reclamation in two ways

• The development of roots improve the permeability and

infiltration capacity of soil.

• CO2 released into the soil by roots increase solubility of

CaCO3.