Earth needs to be nurtured with mother’s care because earth gives everything for sustaining life. Soils that form one of the most precious natural resources of earth. For sustainable agricultural production it is necessary to focus attention on the soil and climate resource base, current status of soil degradation and soil based agro technology for optimizing land use. India lives in villages and agriculture forms the back bone of the country’s economy. This book aims to provide a thorough understanding of the concepts in soil and resource inventory - Concepts - Standard soil survey - Scope and objectives - Soil systematic - Soil mapping units - Methods and types of soil survey - Soil maps. Soil Classification - Modern Soil Taxonomy - USDA System - Diagnostic horizons-Soil orders - Soils of India and Tamil Nadu. Soil survey reports-Soil Survey Interpretations - Land Capability Classification - Soil and Land Irrigability Classification Storie’s Index Rating - Fertility Capability Classification- Land suitability for field crops, horticultural crops and forest trees - Land Use Planning concepts and objectives. The book has been compiled in order to provide sound knowledge and to improve the technical competence of the Bachelor Degree of Agriculture students based on Undergraduate curriculum. The topics and contents have been presented to make it easy understanding for the students.

1.1. Soil Resource Evaluation Soil is the essence of life on the planet Earth. It has sustained humanity and human civilizations through five functions (Karlen et al. 1997) viz., i) sustaining biological activity, diversity and productivity; ii) regulating and partitioning water and solute flow; iii) filtering, buffering, degrading, immobilizing and detoxifying organic and inorganic materials, including industrial and municipal byproducts and atmospheric decomposition; iv) storing and cycling nutrients and other elements within the earth’s biosphere; and v) providing support to socioeconomic structures and protection for archaeological treasures associated with human habitation. Reeling under the pressure of increasing food, fodder, feed, fibre and fuel production, soil has been used as a medium of plant growth with considerable reliance on external supply of major nutrients, irrigation water, plant protection chemicals, etc. Although soil, a product of millions of years of weathering, has supported various forms of terrestrial life, its sustainable management holds the key for meeting the basic requirements of burgeoning population and development commitments. So intense has been the pressure of increasing food, fodder, feed, fibre and fuel production that the soil has been exploited often exceeding its carrying capacity. The soils are increasingly used for agricultural and non-agricultural uses, such as disposal of farm, urban and industrial wastes, ensuring environmental safety etc. This is possible by the judicious use of this resource. A clear and intimate knowledge of the kinds of soils and their extent of distribution are essential prerequisites in developing rational land use plans for agriculture, forestry, irrigation, drainage, etc. soil resource inventory or mapping provides an insight about their potentials and limitations. It is therefore imperative to prepare an inventory of this resource for developing optimum land use plan and conservation plans.

Soil survey is essentially a study and mapping of soils in their natural environment. It is the systematic examination, description, classification and mapping of soils of an area. 2.1. History of Soil Survey in India The original investigations on Indian soils were carried out by Voelcker dates back to 1893 and by Leather to 1898.They classified the soils of the country into four major groups, namely the Indo-Gangetic alluvium, the black cotton soil or regur, red soil and laterite soil. Schokalskaya (1932) has published a soil map of India based on the Russian concept which describes 16 soil groups such as climate,vegetation, soil-forming materials, salinity, alkalinity, swamps and peats (Bhattacharyya et al. 2013). In 1935,Wadia and his co-workers collected a soil map of India with significance on geological formations and classified the soils as red, black (regur), laterite and lateritic soils of Peninsular India and also Indo-Gangetic Plains (IGP) which includes delta, desert, bhabar, terai and alkali soils. Vishwanath and Ukil (1943) published a soil map of India by placing the soils in different climatic zones for the first time. This was prepared by Imperial Agricultural Research Institute, New Delhi, and published in the year 1943. There were 17 kinds of soils identified, viz., deep black soils, black clay soils, black loamy soils, black sandy soils, red sandy soils, brown sandy soils, red and yellow soils, dark reddish brown soils, mixed soils (white and yellow), alluvium (Indus, Gangetic, Brahmaputra), coarse alluvium, soils of swamp lands, calcareous soils, usar soils, kallar soils, coastal alluvium soils and soils of Great Himalayan Ranges. Soil survey works were started in 1954, in most of the states as a part of their agricultural development programme, and Bihar (Soil Survey and Land use Planning Scheme, Sabour) was pioneer. In 1954, the soil survey work was started under the leadership of Dr. P. P. Jha following the conventional procedures in Bihar (including Jharkhand) to delineate the soil associations based on geology, relief, physical and chemical characteristics of soils for the first time in India by the then Soil Survey Scheme at Sabour (Mishra et al. 2001; Mishra 2015, 2016). Meanwhile, the National Atlas Organization, Kolkata, prepared a soil map of India in 1957 classifying Indian soils into six major groups and 11 broad types. Murthy and Pandey (1983) applied the working principles of the USDA 7th Approximation in classifying the Indian soils with available data on soil classes and thus used the US system for the first time at great soil group level, which was transformed into a soil map of India on 1:6.3 million scale. Mishra et al. (1994) attempted to propose “Fluvisols” as the 13th Order in USDA Soil Taxonomy for active floodplain soils frequently occurring in different parts of India and elsewhere. Mishra (2015, 2016) proposed a framework of Indian system of soil classification mainly based on land use options.

Soil Classification Soil classification deals with the systematic categorization of soils based on distinguishing characteristics as well as criteria that dictate choices in use. Soil classification is grouping of objects in orderly and logical manner into classes based on the properties of soils (differentiating characters) for the purpose of studying and identifying them. The soil individuals are grouped into classes of the lower category (soil series) which are grouped into classes of higher categories (soil orders). The lower categories are defined by large number of differentiating characters and higher category by a few differentiating characteristics. For soil resources, experience has shown that a natural system approach to classification, i.e. grouping soils by their intrinsic property (soil morphology), behaviour, or genesis, results in classes that can be interpreted for many diverse uses. Differing concepts of pedogenesis and differences in the significance of morphological features to various land uses can affect the classification approach. Despite these differences, in a well-constructed system, classification criteria group similar concepts so that interpretations do not vary widely. This is in contrast to a technical system approach to soil classification, where soils are grouped according to their fitness for a specific use and their edaphic characteristics.

In recent times, the interpretations cover a wide spectrum of soil uses, both for agricultural and non agricultural (sewage and human waste disposal, high way construction, water and gas supply, recreation, wild life, urban and industrial structures) and many specialized uses. Soil survey if correctly carried out according to scientific principles, can provide the data base for various interpretations. This is because the same soil properties determine the behaviour of a soil for a variety of different uses. For instance, the content of clay, silt and sand, the shrink and swell behaviour, the permeability of soil to water and air, content of calcium carbonate, salts, organic matter, gypsum, soil depth, depth of ground water, hard pan formation, co-efficient of linear extensibility, water holding capacity etc. are examples of such properties that are important to plant growth and these properties also strongly influence non farm uses. Some examples in support are A hard or petrocalcic horizon or other slowly permeable layer (clay-pan) in a soil restricts the movement of air and water, thus adversely affecting the plant root growth. Such a layer limits the soils suitability for septic tanks and other onsite waste disposal. It also makes a poor sub grade for high way construction. A soil high in soluble salts is a poor medium for plant growth; it is also corrosive to iron and steel structures, such as pipelines and fences, causing high maintenance and repair costs. High organic matter content is generally favourable to plant growth, but it is a limitation for road construction. The strongly gypsiferous soils (gypsum content >10%) are considered unsuitable for arable crop cultivation because of its dissolution under irrigated or even moderate rainfall and making the surfaces uneven through the developments of sink holes. Such soils are unsuitable for irrigation and drainage canal networks and also for construction of roads, bridges etc. The shrink- swell soils of India (vertisols) because of summer monsoon rains are suitable for growing a “kharif” crop but are very dangerous for construction of roads, air strips, buildings, laying gas, water pipelines which get distorted, develop cracks and lead to sunken floors etc.

Land is merely an area of the earth’s surface comprising all physical, chemical and biological environments that influence the land use (FAO ,1976). Land refers not only to soil but also to climate, landforms, hydrology, geology, natural vegetation including fauna and flora. The land use simply means management of a land for specific uses to meet the human needs in all rural, urban and industrial context, whereas the land use plan refers to a coherent set of decisions about the ways to achieve the desired level preferably on economic background. Thus, the land use planning is the systematic evaluation and assessment of a land and associated attributes for the purpose of identifying the best land use options beneficial to landowners or users without degrading the land resources or environment. It includes not only the landowner or users, but also the policy or decision makers as well as economic experts for financial measures from planning stage or logistic planning to execution. Land cover Relates to the type of feature present on the surface of the earth e.g., Fields, trees, concrete high ways. Land use Relates to the human activity associated with a specific piece of land. The same land would have a land cover consisting of roofs, pavements, grass and trees. The land use in an area is really an intervention by the people over the existing natural eco-environment for satisfying their needs. Land cover is distinct from land use despite the two terms often being used interchangeably. Land use is a description of how people utilize the land and socio-economic activity - urban and agricultural land uses are two of the most commonly recognised high-level classes of use. At any one point or place, there may be multiple and alternate land uses, the specification of which may have a political dimension.