Land is a limited resource in all countries. With time, the situation will worsen as soil degradation reduces the productivity of the soil. Those countries which have adopted large-scale irrigation programs generally risk salinization or alkalization, which slowly but surely develops when arid and semi-arid environments are irrigated. There are many stresses experienced by a land resource system and its soils. However, there are frequently one or two major stresses that prevent the use of the land for most agricultural purposes. Causes of stressed systems are numerous. They include removal of nutrients, development of acidity, salinization, alkalization, destruction of soil structure and loss of organic matter. In some regions of the world, a combination of these results in such degradation that the term "desertification" is popularly used. In the semi-arid and arid parts of the region, there are expanses of saline and alkaline soils. However, salinity induced by irrigation is also consuming large areas of land in the semi-arid regions. In addition to availability of moisture, salinity is a major problem of the semi-arid tropics. Pakistan spreads over an area of 79.61 million hectares (M ha), however, only about one-fourth of this area supports the population of 221 million that is equivalent to 2.83% of the total world population. Land is the major non-renewable resource and faces the biggest threat of degradation. Land resources of the country are degrading at an alarming rate and causing environmental problems. Almost 70 % of the total area of the country falls under arid and semi-arid regions while in irrigated belt salinity is threatening the normal agriculture. Keeping in view above problem, this course has been designed with following aims and objectives: Aims of the course: This course will create awareness among the students about the problems, reclamation and management of salt-affected soils. This course also aims at understanding the problems of irrigation waters and strategic treatment/management options about the sustainable and safe use of such low-quality waters in agriculture. In addition, the students will be equipped with pre-requisite knowledge and skills necessary to become a good researcher. This will in turn help develop research aptitude among the graduates which will go long way in their practical carrier. Objectives of the course: Implications of excess salts and water in soil and their mitigation options will be studied in this course. After studying this course, a student should be able to understand: 1. Issues related to salt-affected soils and low-quality waters. 2. Mathematical relationships to calculate SAR of soil solution from SAR of irrigation water 3. Calculate average root zone salinity and salt balance. 4. Strategies for the reclamation and management of salt-affected soils. 5. Management of reclaimed soils. 6. Irrigation water quality and guidelines/options for brackish water use on sustainable basis. 7. Selection of salt tolerant crops for profitable crop production.

Objective and Learning Outcome

Sources, processes, accumulation and implications of excess salts and water in soil and their mitigation options are discussed in this course. The students should be able to identify sources and diagnose causes of excess salts and water, effectiveness of reclamation options and preventive measures, and select salt tolerant crops for profitable crop production. 

Course Contents

1. Salt-affected and waterlogged soils in Pakistan and global perspective
2. Genesis of saline and sodic soils
3. Classification systems of salt-affected soils
4. Effects of salinity and sodicity on soil characteristics
5. Derivation and applications of Gapon equation
6. Plant responses to saline and sodic conditions
7. Amelioration strategies and economic feasibility for salt-affected soils
8. Water requirements for reclamation
9. Concept of leaching fraction and its applications
10. Soil waterlogging
    1. Causes
    2. Soil and plant responses
    3. Amelioration strategies
11. Environmental and economic impacts of salinity and waterlogging

Books Recommended

1. Ghafoor, A., M. Qadir and G. Murtaza. 2004. Salt-Affected Soils: Principles of Management. Allied Book Centre, Urdu Bazar, Lahore, Pakistan.
2. Maliwal, G.L. and L.L. Somani. 2010. Nature, Properties and Management of Saline and Alkali Soils. Agrotech Publishing Academy, Udaipur, India.
3. Pessarakli, M. (ed.). 2010. Hand Book of Plant and Crop Stress. 3rd Ed. Marcel & Dekker Inc., NY, USA.
4. Pierzynski, G.M., J.T. Sims and G.F. Vance. 2000. Soils and Environmental Quality. CRC Press. Boca Raton, FL, USA.
5. Schjonning, P., S. Elmholt and B.T. Christensen. 2004. Managing Soil Quality Challenges in Modern Agriculture. CABI Publisher Cambridge, MA, USA.
6. Singh, N.T. 2005. Irrigation and Soil Salinity in the Indian Subcontinent: Past and Present. Lehigh University Press, Bethlehem, Israel.