Soil is the most fundamental resource to fulfill basic requirements of food, fiber and shelter of human race. Soil forms basis for all terrestrial life. Soil provides a wide range of ecosystem services that make humankind to survive and progress. Soils are complex mixtures of minerals, water, air, organic matter, and countless organisms that are the decaying remains of once-living things. It forms at the surface of land and is the “skin of the earth”. Soil is capable of supporting plant life and is vital to life on earth.

Soil is the most fundamental resource to fulfill basic requirements of food, fiber and shelter of human race. Although soil is perceived as something of insignificant value and it is considered as dirt but humans cannot survive without soil. Soil forms basis for all terrestrial life. Soil provides a wide range of ecosystem services (Table 1) that make humankind to survive and progress.

Soil genesis, or pedogenesis, is the combined effect of physical, chemical, biological and anthropogenic processes working on soil parent material (rocks & minerals). Soil is said to be formed when organic matter has accumulated and colloids are washed downward, leaving deposits of clay, humus, iron oxide, carbonate, and gypsum, producing a distinct layers. These constituents are moved from one level to another by water and animal activity.

Soil physics is the study of soil’s physical properties and processes. Soil physics deals with the dynamics of physical soil components and their phases as solid, liquids, and gases. Physical properties of soil include texture, structure, density, porosity, consistency, temperature, colour and water content. The physical properties depend on the amount, size, shape and arrangement and mineral composition of its particles , kind and amount of organic matter and the volume and form of its pores and the way they are occupied by water, air at a particular time.

Soil Chemistry is the study of chemical composition of soil in relation to crop needs. It deals with the chemical constitution of the soil, the chemical properties and the chemical reactions in soils. Traditional soil chemistry focuses on chemical and biochemical reactions in soils that influence nutrient availability for plant growth, and potential environmental consequences associated with inorganic and organic fertilization. Soil chemistry has increasingly focused on soil genesis and the environment over the past few decades.

Soil minerals are naturally formed inorganic compounds with definite chemical composition and characteristic geometric (crystalline) form. They are classified as primary and secondary minerals, silicates and non-silicates minerals, and crystalline and non-crystalline minerals. Primary minerals have not been significantly altered chemically since deposition or crystallization from molten magma and are usually found in the sand and coarse silt fractions. Secondary minerals form as a result of the alteration of primary minerals by weathering and are found in the clay and fine silt fractions.

Soil organic matter is any material produced originally by living organisms (plant or animal) that is returned to the soil and goes through the decomposition process. At any given time, it consists of a range of materials from the intact original tissues of plants and animals to the substantially decomposed mixture of materials known as humus. Soil organic matter (SOM) is the organic component of soil, consisting of three primary parts including plant residues and living soil organisms, decomposing (active) organic matter, and stable organic matter (humus). Most soil organic matter originates from plant tissue.

Study of living organisms in soil is referred to as soil biology (Greek word bios= life, logos = study). The soil is teeming with millions of living organisms which make it a living and a dynamic system.

Soil degradation is defined as a decrement in the soil health status resulting in a diminished capacity of the ecosystem to provide goods and services for its beneficiaries. Degraded soils have a deteriorated health status such, that they do not provide the normal goods and services of the particular soil in its ecosystem. Soil degradation is the physical, chemical and biological decline in soil quality.

The soils which owe characteristics that they cannot be economically used for the cultivation of crops without adopting proper reclamation measures are known as problematic soils. Different kinds of problematic soils viz., Physical, chemical and biological problematic soils exists and pose problems of crop production.

Soil fertility is defined as the quality that enables the soil to provide proper nutrient compounds in proper amounts and in proper balance for the growth of specified plants. Soil fertility is also defined as the ability of soil to supply adequately the nutrients normally taken from the soil by plants.

The word “Manure” is originated from the French word “Manoeuvrer” which refers to “work with soil”. The word Manure is also originate from Latin word “Manu” (hand) and operate (to work). Manures are the substances which are organic in nature, capable of supplying plant nutrients in available form, bulky in nature having low analytical value and having no definite composition and most of them are obtained from animal and plant waste products. Formerly, the word in use was “Dung ”in English (at present fertilizer).

Soil is a dynamic, vital living natural resource. Soil health is the condition of the soil and its potential to sustain biological functions, maintain environmental quality, and promote plant and animal health. It is qualitative trait of soil. Healthy soil is the foundation for profitable, productive, and environment friendly agricultural systems.

Soil pollution is defined as presence of xenobiotics (e.g. chemical compounds, radioactive elements) that alters the soil properties viz., both chemical, physical and biological properties of soil. Soil pollution, including heavy metals, may be of natural origin, like volcanic eruptions, atmospheric lightning, animal excrements or ore leaching. Nevertheless, human activity and mostly chemical industry, mining and metallurgy, as well as municipal waste management and traffic emissions are the main source of environmental pollution.

Geographic location of India is in Northern hemisphers and located between 80 4' & 370 6' N latitude and 640 7' & 970 25' E longitude. Extent of area is 329 M Ha or 329 x 104 Sq.Km or 3.29 MSq.Km. The physiography of India can be broadly grouped into triangular plateau, mountains, Indo-gangetic plains and islands. India is divided into twenty agro ecological regions and sixty five agro ecological sub regions as per NBSS and LUP. Agro ecological regions( AER) is referred to identification and demarcation of land units having comparable landform, soils, bioclimatic conditions and the length of growing period (LGP).

Water required for irrigation of cropped land is being degraded in terms of quantity and quality due to fast increasing demand for its use. Furthermore, the soil quality and crop productivity is linked to the quality of the water available for irrigation. In general, evaluation of irrigation water quality should focus on salt content, sodium concentration, the occurrence of nutrients and trace elements, alkalinity, acidity, and hardness of the water.

Abrol, I.P., Yadav J.S.P. and Massoud, F.I. 1988. Salt-affected soils and their management. FAO Soils Bulletin No. 39, Food and Agriculture Organization of the United Nations, Rome.