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The soil is the soul of infinite life and Sadguru says that our body is essentially soil and water. The quality of our soil and water determines the quality of our food, our body, and our life. These two sayings show the importance of soils in our life, nature and environment. This book, “Soil: A Vulnerable Natural Resource” is the sequel of my more than 38 years of teaching, research and extension of knowledge of soil science. The course content of this book is based on the syllabi of courses, Fundamentals of soil science of B.Sc. (Agriculture) and B.Sc. (Horticulture) and course, Geology & Soil Science of B.Sc. (Forestry) according to the Dean’s Committee of ICAR, New Delhi. This book is also useful for the course, Principles of soil science of B.Tech. (Agriculture Engineering) besides PG students, NET, JRF, SRF, ARS etc. aspirants’ and extension personnel. Soils are used in buildings, roads, brick kilns, naturopathy etc. Soils are a basic requirement of agriculture and provide nutrients, water, air, heat and mechanical support to arable plants to produce the food, fodder, fibre, fuel wood and other plant products for humans and animals. Soils also naturally treat depression by stimulating serotonin production, which makes you relaxed and happier. The earthy fragrance, Petrichor and Geosmin, coming out from soils just after the first summer rain fascinates us. Now Soil Scent, Mitti attar, is also available in the market. Even use of Multani Matti (Fuller’s Earth) as soap, shampoo, and face pack as well as mud bath are common in rural folk to high end spa.

This chapter presents a birds’ eye view of the soil to develop the interest among the readers to know more about the fundamental concepts of soil. Soil is a major determinant of terrestrial ecosystems and helps in the distribution of land flora and fauna. Soils are sources, transformers and stores of plant nutrients. Soils are the recycling places of plant and animal residues and wastes. Soils are also the screen and filter of pollutants in many ways, forms and degrees. Soils are the main link and recharger of hydrological cycle. Soils influence radiant heat exchange, temperature change and land surface reflection characteristics. Soils are important sources and sinks of biogeochemical cycles of carbon dioxide, methane, nitrogen oxides and sulphur dioxide. Soil is used in buildings, roads, brick kiln, naturopathy etc. Soils are good record of past climatic conditions and human activities, as they have some stable features originated from the interactions of climate, organisms, relief, parent material and time. Soil provides nutrients, water, air, heat and mechanical support to arable plants to produce the food, fodder, fibre, fuel and other plant products for human and animals. Mainly the soil is studied as a natural body and as a medium for plant growth.

Genesis of Soil World’s geography is very widely diversified in relief showing various features like mountains and hills covered with snow and trees, glaciers, higher altitudes to plain to lowest valleys, forests to barren lands, fertile fields to waste lands, plateaus, deltas, swamps, lowlands, deserts etc. Temperature varies from arctic cold to scorching hot of equator, Rainfall from aridity to per humidity. All these situations and conditions under different sets of combinations generate and develop numerous types of soil from a single type of parent material. Therefore, many types of soils may develop at a smaller area. Physical, chemical and biological weathering processes disintegrate and decompose various rocks and minerals to make asymmetrical soil parent material. This parent material is converted in to the soil profile by soil forming processes in the presence of soil forming factors. Soil genesis is defined as mode of formation of the soil from the parent material due to the action of soil forming factors and processes. Parent material, Factors of soil formation and Processes of soil formation, are three main part of soil genesis. These are described here: 1. Parent Material, 2. Classification of parent material, 3. Factors of soil formation, 4. Processes of soil formation, 5. Types of soil forming processes.

Physical Properties of Soil Physical properties of soil have many important roles in the crop production. The basic requirements for germination, seedling emergence and root development are adequate moisture and aeration, optimum temperature and absence of mechanical hindrance. After germination the further development of plant is also governed by physical conditions of soil. Soil texture, soil structure, soil density, soil consistence, soil water, soil air, soil temperature and soil colour are main physical properties of soils also affecting mechanical behaviour of soils. These are described here. 1. Soil Texture The weathering divides larger particles of rocks and minerals in to the smaller ones. This process goes continuously. Thus, particles of different sizes ranging from large fragments of rocks to the very fine clay minerals are found in soil. However, for texture particles less than 2mm diameter is considered. The relative amount of these particles indicates the soil type also. Such as sandy soils contain more amounts of coarse particles i.e., sand and clayey soils are rich in fine particles. The rock and mineral particles having diameter less than 2.0 mm and come between specifies size are called as soil separates. International society of soil science (ISSS) and United States Department of Agriculture (USDA) systems are Generally, followed to classify the soil separates. This classification is given in table 3.1.

Vulnerability of Soils Soil vulnerability, Soil degradation, soil vulnerability index Water and wind erosion, depletion of soil organic matter, loss of plant nutrients, salinity, alkalinity, acidity, pollution and contamination, compaction, sealing, crusting, water-logging, aridity, lowering of water table, over grazing, deforestation, landslide, loss and change in soil biodiversity, Abandoned mines etc. Soil vulnerability, Soil Degradation, Soil Vulnerability Index The terms vulnerable and vulnerability are now bites of every one and used for everything. Vulnerable means to the possibility of attack or harm by any mean. Human beings are vulnerable to Covid-19, computers are vulnerable to virus, softwares are vulnerable to hackers and attackers to control system, environment is vulnerable to pollution. Vulnerabilities refer to the lack of ability to resist the effects of the aggressive environment. Soils are vulnerable to numerous threats like water and wind erosion, depletion of soil organic matter, loss of plant nutrients, salinity, alkalinity, acidity, pollution and contamination, compaction, sealing, crusting, water-logging, aridity, lowering of water table, over grazing, deforestation, landslide, loss and change in soil biodiversity etc. However, this book will describe some of the most pertinent vulnerabilities for soils.

In the earlier chapter the major soil vulnerability namely, water and wind erosion, depletion of soil organic matter, loss of plant nutrients, salinity, alkalinity, acidity, pollution and contamination, compaction, sealing, crusting, water-logging, aridity, landslide and abandoned mines were described. In this chapter two more parts, Importance of remote sensing (RS) and geographical information system (GIS) in soils and Watershed management are also included after seeing their importance in agriculture and soils. Restoration means that by various actions or processes to return something to its original owner, site, place, or condition. In this context our aim is to restore our mother soil from various vulnerabilities by different actions and processes to its natural and original condition up to the maximum possible extent. Management is defined as the scientific methods to attain targeted production through planning, organising, training and fixing targets for employees. Therefore, after the restoration, soils should be managed according to scientific method of action by scientifically selected and trained staff to perform the assigned responsibilities, effectively, efficiently and rapidly within stipulated period. On these guidelines restoration and management of vulnerabled soils is described here,