eChapters

The phenomena related to the retention and movement of water in soils, its uptake and translocation in plants and its loss to the atmosphere are all energy related. The more strongly water is held in the soil, the greater is its energy. It means that if water is to be removed from a moist soil, work has to be done against the adsorptive forces. The water movement is always from a zone where the free energy of water is high (standing water table) to one where the free energy is low (a dry soil). This is called soil water energy concept.

17.1. Soil Water Potential

The free energy of soil solids for water is influenced by:

i) Matric force: the attraction of the soil solids for water (adsorption) which markedly reduces the free energy (movement) of the adsorbed water molecules.

Water is the elixir of life. It is required for the evapo-transpiration of growing plants. Water acts as a solvent and, together with dissolved nutrients, makes up soil solution from which plant roots derive nutrients. Soil water content controls soil air and soil temperature.

16.1. Forces of Water Retention

The forces responsible for water retention in soils are adhesion and cohesion. Adhesion refers to the attraction of solid surfaces for water. Cohesion refers to the attraction of water molecules for each other.

The force with which the soil particles retain water is defined in terms of pF scale (Schofield, 1935). pF is defined as “the logarithm to the base 10 of the numerical value of the negative pressure of soil moisture expressed in centimetres of water.”

Water is absolute necessary constituents for the survival and growth of all the living substances on earth. It is the most essential ingredients for many of the physiological and metabolic process in plants, like photosynthesis to form sugars, translocation of cell constituents and maintenance of cell turgidity. Soil, being an adsorbent of water received from precipitation or rainfall acts as reservoir to meet requirement by plant during growing season. Water retained in the soil serves as solvent to dissolve salts and nutrients and as a carrier to translocate them for absorption by plants. It plays significant role in weathering reaction, soil forming processes and profile development. Water is also important for growth and activities of microorganisms influencing decomposition of organic matter, transformation of mineral nutrients and other physical, chemical and biological properties in soil. This chapter deals with the retention and movement of water in soils to obtain better understanding of soil-water-plant-atmosphere relationships.

The soil consists of many solid particles of different sizes and is capable of absorbing and retaining water in the soil within certain limits when water is received through either from precipitation or by irrigation. The water that is held in the soil is called soil water (Fig.4.1). It can exist also in the form of water vapour as well. The crop production depends upon the soil water. All the water that is present in the soil may not be available for plants.
The water availability to the plants from the soil depends upon some physical properties of the soil as well as on the physical processes that govern the existence of water in the soil. Therefore, it is necessary to understand about the relationships that govern the water availability in the soil as explained in the following text-
4.1. Energy Concept of Soil Water
Soil water energy concept is all about potential energy, gravitational potential, osmatic potential, pressure potential energies.
4.1.1. Soil Water Energy: The total energy state of soil water is defined by its
equivalent potential energy as determined by various forces acting on the water per unit quantity. Different energies are involved including kinetic and potential energy.

The soil is a heterogeneous, polyphasic viz., solid, liquid and gaseous, particulate, disperse and porous system (Fig. 3.1). The solid phase constitutes the soil matrix, the liquid phase consists of soil water, which always contains dissolved substances so that it should properly be called as soil solution and the gaseous phase is the soil atmosphere.

Increasing susceptibility of vegetables to various biotic and abiotic stresses and very high cost of hybrid seeds has warranted the attention of the vegetable growers to improve the nursery raising technology of vegetables. Now-a-days protected nursery raising of vegetables has become a full flagged industry in several developed countries like Israel, Japan, Spain, Netherlands, USA etc. In countries like Israel no vegetable grower is growing his own nursery, but they are getting the required kind of seedlings from an established nursery owner on pre- order basis. Similar system of nursery raising is also prevalent in several other advance countries. In those situations where vegetables are being grown under protected conditions it becomes pre-requisite to raise the required vegetable seedlings only under protected environment to get virus free healthy seedlings.

Raising nursery from seeds provide an easy and convenient way to nourish tender and young seedlings in a well managed, small and compact area for better germination of small and costly seed. In general, vegetables crops are divided into three groups according to their relative ease for transplanting. Beet root, broccoli, brussels sprouts, cabbage, cauliflower, tomato and lettuce are efficient in water absorption and rapidly form new roots after transplanting. Vegetables crops that are moderately easy for transplanting are brinjal, onion, sweet pepper, chilli and celery which do not absorb water as efficiently as crops that are easy to transplant, but they form new roots relatively quickly. The vegetable crops which are difficult to transplant are: all cucurbits and sweet corn which require special care during nursery raising and transplanting. Seedlings not only reduce the amount of time of the crop but it also increases the uniformity of the crop and harvesting as compared to direct sowing of the crops. Transplanting of seedlings also eliminates the need for thinning and provides very good opportunities for virus free, vigorous and even off-season seedlings if grown under protected conditions in soil-less media. So it becomes necessary to know the protected structures which can be efficiently used for successful raising of vegetable seedlings, suitable types of containers and growing media, method of seeding in containers in soil-less media, growing conditions and water and fertilizer requirement of seedlings along with hardening and transplanting to the field. Protected nursery raising technology is highly suitable and can be established as a small scale industry in major vegetable growing areas of our country by progressive farmers especially in peri-urban areas. By this way the vegetable growers will get virus-free healthy and off season nursery as per their requirement and it generate extra employment in rural areas.

Cation exchange: The ‘soil cations’ essential for plant growth include ammonium, calcium, magnesium, and potassium. There are three additional ‘soil cations,’ which are not essential plant elements but affect soil pH. The additional ‘soil cations’ include sodium, aluminum and hydrogen.

The major distinguishing characteristic of cations is their positive charge. Just like a magnet, a positive charge is strongly attracted to a negative charge. When soil particles have a negative charge, the particles attract and retain cations. These soils are said the have a cation exchange capacity. Although most soils are negatively charged and attract cations.

The ‘soil cations’ are further divided into two categories. Ammonium, calcium, magnesium, potassium, and sodium are known as the ‘base cations,’ while aluminum and hydrogen are known ‘acid cations.’ Unlike the other base cations, sodium is not an essential element for all plants. Soils that contain high levels of sodium can develop salinity and sodicity problems.

The words ‘base’ and ‘acid’ refer to the particular cation’s influence on soil pH. As you might suspect, a soil with a lot of acid cations held by soil particles will have a low pH. In contrast, a highly alkaline soil predominately consists of base cations.

Cations in the soil compete with one another for a spot on the cation exchange capacity (Table 42 and Fig 18). However, some cations are attracted and held more strongly than other cations. In decreasing holding strength, the order with which cations are held by the soil particles follows: aluminum, hydrogen, calcium, potassium and nitrate, and sodium.

The soil–plant relationship is central to crop productivity because soil conditions directly influence root development, water uptake, nutrient availability and plant growth. This chapter focuses particularly on the problems associated with salt-affected soils, including saline, sodic and acid soils. It explains the formation, distribution and characteristics of saline soils and describes the production constraints created by salinity stress. The effects of salinity on plant growth, evaluation of saline soils, reclamation and leaching are discussed together with leaching requirements and crop salt tolerance. Water and nutrient management strategies for saline soils, including the use of biofertilizers, are considered. Sodic soils are examined through their formation, characteristics, exchangeable sodium percentage (ESP) and sodium adsorption ratio (SAR), followed by reclamation practices and amendment use, particularly gypsum. The chapter also addresses acid soils, their formation, chemical characteristics, nutrient availability, plant-growth constraints and amelioration through liming. Calcareous soils and their management are also included, providing a comprehensive treatment of problematic soils affecting soil–plant interactions

The soil-plant-water relationship is a critical aspect of agricultural science, encompassing the interactions between soil properties, plant health, and water dynamics. This article examines the intricate connections that influence plant growth and crop productivity, highlighting the roles of soil texture, structure, and organic matter in water retention and availability. It explores how plants uptake water through root systems and how transpiration affects water distribution within the soil. The study also addresses the impact of irrigation practices and soil management techniques on optimizing water use efficiency in agricultural systems. Understanding these relationships is essential for developing sustainable farming practices that enhance crop yield while conserving water resources.

Water is the most abundant compound on the earth but its sufficient availability is always a big constraint in crop production, particularly in arid and semi-arid areas since agriculture is the last priority for good quality water due to severe competition with public health and industrial demand, hence, the judicious and efficient use of water for irrigation in agriculture needs through knowledge of soil-plant-water relationship. The integrated approach for water management in rain fed areas or irrigated agriculture in soil-plant-atmosphere system helps in the selection of suitable crops and varieties and also helps in improving the crop yield and water use efficiency in relation to water supplying capacity of soil profile depending on its texture and rhizosphere depth. Similarly, atmospheric demand of evapotranspiration by various weather parameters via temperature, relative humidity, radiation, rainfall and wind speed is highly variable during the crop season depending on geographical location and is highly area specific. In irrigated area, the saving of irrigation water through improved management practices will further help in extending the irrigated areas with same amount of water, which will further boost agricultural production and sustainability.

Most of the earth’s total water is contained in oceans (96%), a small portion (2%) as snow and ice and the rest (2%) in the water bodies of the continents. Oceans, lakes, rivers and other water bodies of the earth are called hydrosphere. Continuous circulation of water between hydrosphere, atmosphere and lithosphere is known as hydrological cycle (Figure 12.1). Schematic diagram illustrating the earth’s water cycle– the hydrological cycle.

The soil–plant–water relationship integrates the major concepts of soil-water availability, root water uptake and plant transpiration into a unified system. Water movement through the soil and plant is governed by differences in water potential and by resistance within the water-conducting pathway. This chapter examines water uptake by roots and the process of transpiration, emphasizing the continuous movement of water from soil through the plant and ultimately to the atmosphere. Variations in water potential and water flux within the soil–plant system provide the basis for understanding how water is transported under different environmental and soil conditions. The resistance of the water-conducting system is considered as an important factor controlling water movement. The chapter separately discusses water movement through soil and within plants before connecting these processes with water movement from the leaf surface to the atmosphere. Control of transpiration is also examined, linking plant water relations with environmental conditions and crop water use. The chapter provides an integrated framework for understanding soil–plant–water interactions essential for efficient irrigation, crop productivity and sustainable management of water resources.

The plants collect water by its root system available in the soil medium. A soil rich in nutrients cannot ensure success of crops unless the presence of satisfactory state of water and air, mechanical attributes and thermal regime. The physical properties of soil and plants greatly influence the movement, retention and use of water. The soil should provide sufficient pore spaces and size distribution and decomposition of rocks and for the movement and retention of water for plant needs. Rainwater, irrigation, groundwater, seepage, etc. , contribute in replenishing the water in dried up soils. In all the cases thorough understanding of behavior of water is required to ensure the need of water to plants and optimize the use of irrigation water.

The plants collect water by its root system available in the soil medium. A soil rich in nutrients cannot ensure success of crops unless the presence of satisfactory state of water and air, mechanical attributes and thermal regime. The physical properties of soil and plants greatly influence the movement, retention and use of water. The soil should provide sufficient pore spaces and size distribution and decomposition of rocks and for the movement and retention of water for plant needs. Rainwater, irrigation, groundwater, seepage, etc., contribute in replenishing the water in dried up soils. In all the cases thorough understanding of behavior of water is required to ensure the need of water to plants and optimize the use of irrigation water.

6.1 Soils

Soil is initially formed by the disintegration and decomposition of rocks and minerals and accumulation of biological residues. Usually the outer layer of the land surface is referred

Different kinds of soil water and soil water movement; Water in relation to plant growth and crop production; Soil texture, structure, infiltration and permeability; Bulk density and particle density of the soil; Concept and theories of water retention in soils; Consumptive use and ET; Soil moisture characteristics curves; Different losses of water (seepage and run off) and Soil moisture measurement, stress and plant growth
Soil-Water-Plant Relationships and Irrigation Scheduling Concepts
A good understanding of soil-water-plant relationships is the foundation for understanding irrigation concepts.
Water reaches the soil through irrigation, precipitation, or from groundwater drawn up into the root zone through “capillary action”. To be available to plants, it must be held by the soil strongly enough so it is not lost to gravity before the plant gets it, but not so strongly that the plant cannot extract it from the soil. At the same time, the roots must have sufficient aeration to function properly.
Roots are responsible for obtaining almost all of the plant’s water and nutrients. These substances move through the soil during and after irrigation/fertigation and rainfall. In addition, root systems are continually growing and branching to seek out water and nutrients. Root hairs are very fine structures that extend at right angles to the roots. Water and nutrients predominantly enter the root system via specialized cells near the tips of root hairs.
The xylem is the cellular pathway through the plant that transports water from the roots to the leaves for use in photosynthesis and to cool the plant by evaporation. The process by which water vapour is released to the atmosphere by the leaves and other parts of a living plant, resulting in evaporative cooling, is called transpiration. The xylem also transports water and nutrients to other parts of the plant. In a living plant, the xylem is completely filled with water, just as the veins and arteries of the human circulatory system are filled with blood. The plant needs a continual replacement of water lost through transpiration to keep the xylem full of water, and of course, this has to be accomplished without an organ analogous to a human heart. Tomato plants

14.1. Introduction

Environmental pollution primarily deals with five types of pollution: soil pollution, water pollution, air pollution, sound pollution and light pollution. However, soil, water and air pollutions are considered very important as the pollutants from the environmental compartments may be cycled within themselves, enter the food web and interfere the biological processes adversely of any living species. Soil supplies nutrients and water to plants which, in turn, act as the nutrient supplier to animals and humans. Thus, maintenance of soil quality is considered prerequisite for growth of plants, animals and humans. If soil, water and air are polluted through various mechanisms, living components in the environment are suffered adversely. Soil, water and air pollutions are associated with the build-up of soil contaminants such as toxic organic and inorganic compounds, petroleum hydrocarbons, radioactive materials, salts, disease causing agents etc. above the permissible limit, so that their presence will cast adverse effects on physicochemical and biological properties of soil which in turn exert negative impact on crop growth and on any non-targeted organisms. Common soil contaminants include heavy metals, pesticides, petroleum hydrocarbons, fertilizers if used in excessive amount, and many others. Contamination of the soil, air and water results from intensification of farming activities. Primarily nutrients (particularly nitrogen and phosphorus), sediment, wastes, pesticides and salts are regarded as agricultural nonpoint source pollutant. Realistically, most of the pollutants originate from anthropogenic activities, although there exists many naturally occurring mineral components that may exhibit toxicity towards living system at higher concentration. Land disposal of municipal and industrial wastes, automobile emissions, mining activity, and application of fertilizers and pesticides to agricultural field cause a continuous accumulation of heavy metals and other pollutant components in soils. These pose threats of environmental degradation via soil erosion, loss of biodiversity, climate change etc.

Soil and growing media provide the physical, chemical, and biological foundation for successful horticultural production. This chapter explains soil properties, soil fertility, soil health, growing media, nutrient availability, and principles of plant nutrition. Emphasis is placed on soil testing, pH, electrical conductivity, organic matter, nutrient balance, and crop-specific fertilizer management. The chapter also introduces soilless media used in nurseries and protected cultivation. Understanding root-zone conditions is essential because horticultural crops are highly sensitive to water, aeration, salinity, and nutrient imbalance. Sustainable approaches such as composting, mulching, biofertilizers, and integrated nutrient management are discussed to maintain productivity while improving soil health and resource-use efficiency.

The word soil is derived from the Latin word ‘Solum’ means soil. In general the top 15-20 cm cultivated layer is referred as soil. It is a loose and unconsolidated outer layer of the earth crust that is crumbly and powdery in nature. Soil below the plough layer is called subsoil.

Soil is formed by weathering of rocks. Weathering may be physical or chemical or both. Factors of soil formation are parent material, climate, living things-plants, animals and microorganisms, topography and time. Soil formation is a function of parent material (P), climate (C), topography (T_o), life (L) and time (T) which is represented by f(P C To L T).

Soil  and its Components
Soil
Soil is a three dimensional, transferable natural material which is found on the earth crust and provides natural medium to plant growth. OR
Soil is the upper most loose layer of the earth, suitable for plant growth. 
Different scientists defined ‘SOIL’ in different ways:
Buckman and  Brady defined soil as  “A dynamic natural body on the surface of the earth in which plants grow, composed of mineral and organic materials and living forms”.

Introduction Soil, often referred to as the “skin of the earth,” is a critical component of our planet’s ecosystem, serving as the foundation for all terrestrial life. This chapter explores the science of soil, delving into its formation, classification, and the complex properties that define its role in agriculture and environmental sustainability. Understanding soil is fundamental to addressing global challenges such as food security, climate change, and sustainable land management. The chapter begins with an examination of soil formation and classification, providing insights into the diverse types of soils that exist across different landscapes. It then discusses the physical and chemical properties of soil, including their impact on soil health and fertility. The role of soil microbiology is highlighted, emphasizing the importance of microorganisms in maintaining soil health and promoting plant growth. As we progress through the chapter, we explore modern concepts in soil science, including sustainable soil management practices and their significance in mitigating the effects of global warming. The chapter also addresses the crucial role of soil in food security, demonstrating how effective soil management can enhance agricultural productivity and resilience in the face of climate change. Finally, the chapter touches upon the threats to soil health and the importance of sustainable soil management in ensuring a prosperous future for all. Soil science is a vital discipline within agriculture that focuses on the study of soils and their properties. This chapter delves into various aspects of soil science, including soil formation and classification, soil physical and chemical properties, soil fertility and nutrient cycling, soil conservation and erosion control, and soil microbiology and soil health. Soil is the foundation of agriculture, providing the medium for plant growth and supporting the intricate web of life that sustains our ecosystems. Understanding the science of soil is essential for optimizing crop production, protecting natural resources, and ensuring sustainable land management practices. In this chapter, we will explore the fascinating world of soil science, delving into its various aspects to gain insights into soil formation, composition, fertility, and conservation. By understanding the principles and processes underlying soil science, we can make informed decisions to enhance soil health, maximize nutrient availability, mitigate erosion, and promote sustainable agricultural practices.

Water is one of the most important resources governing crop production in irrigated agriculture, and its behaviour within soil determines the availability of water to plants. This chapter presents the fundamental relationship between soil and water, beginning with the importance of soil water in crop production and the classification of soil water. Soil moisture constants and methods for measuring soil moisture content are discussed to explain the different forms and availability of water in the soil profile. The chapter introduces the potential concept of soil water and the components contributing to total soil water potential, including potential energy. Available water capacity is examined in relation to plant water supply, while capillarity and water retention explain how soil texture and pore characteristics influence water storage. The soil-water characteristic curve provides a basis for understanding changes in water content with soil-water potential. Soil-water hysteresis is also discussed to explain differences in wetting and drying behaviour. These concepts provide an essential foundation for efficient irrigation, crop water management and sustainable use of soil water resources

oilless culture is a method of growing plants without soil. It is an artificial means of providing plants with support and a reservoir for nutrients and water. The simplest and oldest method for soilless culture is water culture or solution culture, where inorganic chemicals are dissolved in a vessel containing water to supply all the nutrients to plants. This method was originally termed hydroponics (water working) by W.F. Gericke in the 1930s. Over the years, hydroponics has been used sporadically throughout the world as a commercial means of growing both food and ornamental plants. Today, it is used widely in research facilities as a technique for studying plant nutrition.

Gravel or sand is sometimes used in soilless systems to provide plant support, and retain some nutrients and water. The retention of nutrients and water can be further improved through the use of sphagnum peat, vermiculite, or bark chips. These are the most commonly used materials, but other material such as rice hulls, bagasse (sugarcane refuse), sedge peat, and sawdust are used sometimes as constituents in soilless mixes.

1.1 THE IMPORTANCE OF SOILS

Soils are the medium in which crops grow, and so they are essential to the provision of the food and fibre to sustain mankind. But besides the immense importance of this role they are an essential component to life as we know it because of their action as a buffer to control the flow of water between sky, land and sea. They are also a sink, and usually a safe sink, for many of the chemicals that might otherwise make life difficult or unpleasant.

As with other natural resources, it is important that soils are used conservatively, so that the advantages we enjoy from them now can continue to be enjoyed in the future. To do this we need to understand them, to understand the flow of nutrients from soil to plants, and back to the soil or the sea in food chains and water flow. We need to understand the processes by which rocks alter to form soils, and how fast or how slowly the process occurs in different conditions. We need to understand the decay of plant materials in the soil, and how the products of decay help to make the soil a better place for plants to grow.

The chemistry of the constituents of soils, and of the processes by which changes occur, is not simple. Nevertheless we have learnt much about it, and can apply that knowledge to ensure that soils continue their important functions, and are not exploited so that they become infertile, nor used in such a way that the fertile topsoil is lost by erosion by wind or water.

Soils play a vital role in the health of ecosystems in the world. Soils connect with air, water, rocks and organisms and are responsible for a multitude of functions in the global ecosystem services. These functions include providing habitat for most living things, air composition and quality, temperature regulation, carbon and nutrient cycling, water cycling and quality, and natural waste recycling. Mankind cannot survive without these soil functions.

30.1. Habitat

Soils are the environment in which plants grow. They provide heat, nutrients and water to nurture plants to maturity. These plants, together with other plants and organisms, create ecosystems. These plants then provide valuable habitat and food sources for animals, bacteria and other things. Ecosystems depend on the soil and soils determine the nature and kind of ecosystems.

LAND VERSUS SOIL

Land is a part of Earth’s surface that is not covered by water. It is used for agriculture, building houses, of?ce buildings, schools, hospitals, roads, railroads and even water canals. Land is measured by area [length (l) × width (w)] and the units are square meters (m²), square centimeters (cm²) etc. On the other hand, soil is Earth’s crust, which could vary from a few centimeters to a few meters in thickness (depth), needs a measure of volume [length (l) × width (w) × depth (d)] and the units are cubic meters (m³), cubic centimeters (cm³) etc. Soil is thus a three-dimensional natural body on Earth’s surface that provides anchorage to growing plants/ trees and shelter to soil biota and is responsible for the storage of water and plant nutrients, which are essential for crop production. In addition, it helps in the biodegradation of soil pollutants and puri?cation of ground water, the major source of drinking water in the world. Soil feeds all living beings on Earth and its degradation is one of the reasons for inadequate human nutrition

The arid region in India is spread over in 38.7 million hectare land. Out of the total 31.7 m hectare lies in hot arid region and remaining 7 m hectare comes under cold arid region. The hot arid region occupies major part of northwestern India (28.7 m ha) and a small pocket (3.13 mha) in southern India. The north western arid region occurs between 22°30’ and 32°05’ N latitude and 68°05’ to 75°45’ E, covering western part of Rajasthan, north western Gujarat and south western parts of Haryana and Punjab. About 62% area of arid region falls in western Rajasthan and 20% in Gujarat. Haryana and Punjab together constitute 7% area of arid region. The state wise distribution of arid region is shown in Table 3.1. Further our discussion is based on the majority area of arid region, belonging to Rajasthan, Gujarat, Punjab and Haryana.

Soils of India vary widely among different regions. The first soil map of India was prepared and classified on the basis of existing knowledge of Russian pedological principles. Govind Rajan (1971) and Govind Rajan and Rao Gopal (1978) have discussed in detail the later developments on the preparation of soil map of India and giving the equivalents of different soil groups in US Comprehensive System of Soil Classification. Soil resource mapping was initiated in 1986 and in a span of 10 years (1986-1996), a detailed database in terms of soils, their area and extent, characteristics and grouping following soil taxonomy (Soil Survey Staff, 1999) was created. The present chapter on “soils of India-nutrient status and management concerns” takes into account the following aspects:

India is endowed with varied types of soils and this could be attributed varied relief features, landforms, climatic realms and vegetation types in the subcontinent. In ancient times, soils used to be classified in India into fertile and sterile soils. Later, the inherent characteristics and external features of soils such as texture and colour, were used to classify the soils. Based on texture, soil types were identified as sandy, clayey, loam, etc. In terms of colour, they were red, yellow, black, etc.

Scientific surveys of soils in India have been conducted by various agencies since independence. All India Soil Survey Organization, established in 1956, carried out detailed soil surveys in the catchment areas of major river valley projects like the Damodar Valley. Later, the National Bureau of Soil Survey and the Land Use Planning (NBSSLUP) ofthe Indian Council of Agricultural Research, established in 1976, made extensive studies on Indian soils and classified them as per the USDA SoilTaxonomy

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).

Soil is generally defined as the upper layer of earth in which plants grow. It is regarded as a source of nourishment to all animals, moving or static. From agriculture or crop production point of view, soil is loose earth surface that supports vegetation, its quality, type and density. It is generally treated as a dynamic living entity and its physic-biochemical properties are responsible for its nutritional index. Precision production technology with suitable management is the key factors for its longer sustainability.

1.1. Definition

Soil: Thin layer of earth’s crust made up of disintegrated and decomposed rocks, complex mineral compound, organic matter, water/air and living organism like bacteria, fungi, insects and worms and serves as the natural medium of growth of plants.

Provides nutrients, moisture, anchorage (support) and air to plants.

Parent materials are igneous rocks, sedimentary rocks and metamorphic rocks.

Soil Science: Science dealing with soil (Natural resource) on the surface of the earth, including pedology (Soil genesis, classification and mapping), physical, chemical, biological and fertility properties and their relation to management for crop production.

Soil is defined as the thin layer of earth’s crust made up of disintegrated and decomposed rocks, complex mineral compound, organic matter, water/air and living organism like bacteria, fungi, insects and worms and serves as the natural medium of growth of plants.

• It provides nutrients, moisture, anchorage (support) and provides air to root system.
• There are different soil groups found in varied regions of India.
• Each group differs from other in physical and chemical properties.
• The variation in behaviour is mainly due to the nature of the parent material from which the soils are formed.
• Parent materials are Igneous rocks, sedimentary rocks and metamorphic rocks.
• Physical properties like structure, texture, colour, water holding capacity, depth etc. are to be noted. Chemical properties like the presence of various plant elements, pH, EC, CEC, acidic or alkaline, etc. are considered.

A family of about 90 genera and 3,000 species distributed in both tropical and temperate regions. Central and South America are the chief centres of distribution where over 40 genera are found. About 15 genera and over 90
species have been reported from India. Some of the larger genera along with their approximately world over reported species (Hickey and King, 1988) are Solanum (1700), Cestrum (150), Physalis (100), Lycium (80-90), Nicotiana (66), Capsicum (50), Petunia (40), Hyoscyamus (20) and Datura (10). Solanum tuberosum (potato) and Nicotiana tabacum (tobacco) are the two most utilized plants of Solanaceae.
Petunias, popular bedding plants, with variety of forms, sizes and shapes are employed for landscape planning, garden designs and container gardening. The numerous phenotypes viz., Grandifloras, Multifloras, Millifloras, Waves, Hedgifloras, etc. are complex hybrids. The outstanding marketable series of P. x hybrida have been developed for upright, spreading and semi-trailing to trailing habits.
Selected Indian Genera
Atropa, Capsicum, Cestrum, Datura, Nicotiana, Petunia, Physalis, Solanum, Withania.

Tomato

Genetic Resources

Tomato, a warm season crop, sensitive to frost, is usually cultivated in sub-tropical and mild cold climates. The National Bureau of Plant Genetic Resources (NBPGR), New Delhi, is the main centre for maintenance of tomato germplasms in India. The Bureau has systematically assembled more than 2,900 germplasms. Some of the promising germplasms identified for different traits on the basis of their morphological variations (Fig.1; see Plate-1) are given in Table1.

The family Solanaceae consists of 85 genera, which include both tuberiferous and non-tuberiferous ones.  Brinjal (Solanum sp.), chilli (Capsicum sp.) and tomato (Lycopersicon sp.) are the major fruit vegetables under the family.  In all genera, fruit is an indehiscent berry.
 
A key for the identification of the above  three genera are furnished below:
    A.    Anthers connivant in a cone, longer than filaments
    B.    Anthers dehisce by apical pores or short slits, leaves entire, lobed or pinnatifid : Solanum
    BB.    Anthers dehisce introsely by longitudinal slits, the tips empty, leaves pinnatiset : Lycopersicon
    AA.    Anthers not connivant in a cone, not larger than the filaments, dehisce by lateral slits : Capsicum

The family Solanaceae consists of 85 genera, which include both tuberiferous and non-tuberiferous ones. Brinjal (Solanum sp.), chilli (Capsicum sp.) and tomato (Lycopersicon sp.) are the major fruit vegetables under the family. In all genera, fruit is an indehiscent berry.

A key for the identification of the above three genera are furnished below:

A. Anthers connivant in a cone, longer than filaments

B. Anthers dehisce by apical pores or short slits, leaves entire, lobed or pinnatifid - Solanum

BB. Anthers dehisce introsely by longitudinal slits, the tips empty, leaves pinnatiset - Lycopersicon

AA. Anthers not connivant in a cone, not larger than the filaments, dehisce by lateral slits - Capsicum

In Solanaceae family there are 85 genera, which includes both tuberiferous and non-tuberiferous plants. Among the non-tuberiferous, tomato, brinjal and chilli are the important fruit vegetables.

4.1. Tomato (Lycopersicon esculentum Mill.)

Tomato has originated in Peru and Mexican region of South America. It got its name form the azetc work “Tomatl”. In India tomato is the second largest cultivated vegetable after potato. Though it is produced in almost entire country, the major producer states are Andhra Pradesh, Karnataka, Orissa, West Bengal, Bihar, Gujarat, Madhya Pradesh and Maharashtra.

Cultivar/Varieties: A large number of varieties/hybrids of tomatoes are under cultivation. The most popular among them are Arka Rakshak, Arka Samrat, Arka Saurabh, Arka Vikash, ARTH 3, ARTH 4, Avinash 2, BSS 90, CO3, HS 101, HS 102, HS 110. Hisar Anmol, Hisar Arun, Hisar Lalima, Hisar Lalit, Krishna, KS 2, Matri, MTH 6, NA 601, Naveen, Pusa 120, Punjab Chhuhara, Pant Bahar, Pusa Divya, Pusa Early Dwarf, Pusa Hybrid 1, Pusa Hybrid 2, Pusa Hybrid 4, Pusa Ruby, Pusa Sheetal, Pusa Uphar, Rajni, Rashmi, Ratna and Rupali.

Uses

Tomato adds richness to any dish it is added. Besides using for culinary purpose tomato is also used as salad and dressings and also as adjuvant in several locally available fresh snacks. It is used for thickening of gravies in many Indian curries. As a processed product tomato sauce and ketchup are on top of favourites. It is not only delicious in taste but also rich in its medicinal value. The pulp and juice are mild aperient, a promoter of gastric secretion and blood purifier. It is also considered to be intestinal antiseptic. It is said to be useful in sour mouth, canker of mouth and chronic dyspepsia.

Solanaceae is a plant family that comprising of 2300 species and 85 genera of which, nearly one half of the species belongs to the genus Solanum. The genus Solanum includes both tuber bearing and tuber nonbearing forms. Among the tuber nonbearing forms, the major fruit vegetables growing throughout the world are tomato, brinjal and chilli. They prefer warm humid tropical climate for growth and development. Hence, the agroclimatic regions where this type of climate prevails is suitable for seed production of these vegetables. In addition to this, hybrid vigour has been widely commercially exploited in these crops because of easiness in emasculation and pollination and availability of large number of hybrid seeds per fruit.

Tomato (Solanum esculentum L.)

Tomato is the most important warm season vegetable growing throughout the world. The fruit is valued as salad vegetable and for cooking purpose. It is one of the vegetables from which, a wide variety of processed products are made. The crop is grown throughout the year in one part or other part of the country and it has become one of the indispensable fruit vegetables in our diet. It is rich in vitamin A, vitamin C, niacin, and minerals like calcium, phosphorus etc and it is rich in antioxidant, lycopene which is the carotenoid responsible for the red colour of tomato. Tomato is of recent origin, and it is the native of Peru in South America from where it spread to the entire part of the world.

It is believed that efforts to combat poverty and advance sustainable development must include both the development of livestock and energy-related activities The relationship between energy and livestock in alleviating poverty is less clear and has just recently grown increasingly significant, despite the fact that each of these issues has been identified separately(Steinfeld et al., 2006).

Introduction

Cooking accounts for a major share of energy consumption in developing countries. Fifty per cent of the total energy consumed in India is for cooking (Fritz 1981). Most of the cooking energy requirement is met by non-commercial fuels such as firewood (75%), agricultural waste and cow dung cake (25%) in rural areas. The fuel wood requirement is 0.4 tons per person per year in India. In rural areas firewood crisis is far graver than that caused by a rise in oil prices. Marginal villagers have to forage 8 to 10 hours a day in search of firewood as compared to 1 to 2 hours ten years ago. One third of India’s fertilizer consumption can be met if cow dung is not burnt for cooking and instead is used as manure. The cutting of firewood causes deforestation that leads to desertification. Fortunately, India is blessed with abundant solar radiation (IMD, 1985). The arid parts of India receive maximum radiation i.e. 7600-8000 MJ m^-2 per annum, followed by semi-arid parts, 7200-7600 MJm^-2, per annum and least on hilly areas where solar radiation is still appreciable i.e. 6000 MJm^-2 per annum. Therefore, solar cookers seem to be a good substitute for cooking with firewood.

Principle of cooking

The different methods of cooking of food are boiling, frying, roasting, and baking. For boiling of rice, lentils etc. the temperature of food being cooked is about 100° C while for other methods, high temperatures are required. Heat is supplied at the bottom of the vessel for frying and boiling purposes in conventional cooking. Roasting and baking is generally performed on open fire or in ovens, wherein food is surrounded by hot surfaces and heat is transferred to the food by radiation and convection.

A solar cooker or solar oven is a device which uses the energy of sunlight to heat food or to cook it or sterilize it by means of reflective panels that concentrate the light on to a dark coloured pot in an insulated box.

Introduction

Considering the accountable post-harvest losses which is approximately 30-35 percent, food processing becomes an extremely important sector for preventing the losses and feeding the growing population. The Indian food industry is poised for huge growth, as currently valued at US$ 1.3 billion with compound annual growth rate of 20 per cent per year, increasing its contribution to world food trade every year. In India, the food sector has emerged as a high-growth and high-profit sector due to its immense potential for value addition, particularly within the food processing industry. Increasing population of the country and high cost of fuels have also created a demand for new alternate sources of energies for post-harvest processing of foods. Solar food processing technologies may become a viable option that provides good quality foods at low or no additional fuel costs. The energy policy of the developing countries now focuses on the clean renewable energy to create a further reduction of the petroleum import and to alter the utilization of petroleum energy toward the utilization of solar energy. It is an interesting fact that most of the developing countries fall in the climatic zone where the insolation is considerably higher than the world average of 3.82 kWh m-2 (Majumdar 2015). The daily horizontal insolation of India is approximately 5.80 kWh m-2 (Visavale 2009, Visavale et al. 2011). Solar dyers are an alternative to traditional drying technique and a contribution towards the solution of the problems of the open sun drying from perspective of renewable and clean energy. The International Energy Agency (IEA) declared in its 2011 solar energy perspectives executive summary (SEP 2011): “Solar energy offers a clean, climate-friendly, very abundant and inexhaustible energy resource to mankind, relatively wellspread over the globe. Its availability is greater in warm and sunny countries that will experience most of the world’s population and economic growth over the next decades.

Abstract

Recently, the reduction of post harvest food losses around the globe is a critical issue for ensuring future food security. Drying techniques is important option to prevent losses and preserve food for long time. The solar thermal energy required to remove moisture from the food during the drying process can be optimized by designing suitable solar dryers. Moreover, the application of solar energy in drying of agricultural products has tremendous potential, since it can easily provide the low temperature heating required for drying and helps in reduction of CO2 emissions. Hence, the present chapter deals with descriptions of different types of solar dryers used to dry various types of agricultural food products and design of solar dryers. Also, the heat and mass transfer parameters with respect to various process variables to estimate the performance of the food dryer system were analyzed. The advantages of solar dryers in terms of net CO2 emissions mitigation potential and the quality attributes of dried food products are also discussed. It is suggested that properly designed solar dryers having low operational cost compared to electrically heated dryers may prove to be an energy saving device for drying of agricultural products. However, the techno-economical and environmental aspects of various efficient solar dryers are needed to be further studied for applications in various irregular shaped food products.

6.1. Introduction

Solar crop drying has been demonstrated to be cost effective and an effective alternative to traditional and mechanical drying systems, especially in location with god sunshine during the harvest season. Considerable energy savings can be made with open sun drying since the source of energy is free and sustainable. However, this method of drying is extremely weather dependent and has the problems of contamination, infestation, microbial attacks, etc., thus affecting the product quality. Additionally, the drying time required for a given commodity can be quite long and results in post-harvest losses. Solar drying of agricultural products in enclosed structures by natural convection is an attractive way of reducing post harvest losses and low quality of dried products associated with traditional sun-drying methods. The crop is vulnerable to damage due to hostile weather conditions. The crop is also susceptible to re-absorption of moisture, if it is kept on the ground during periods of no sun, which reduces its quality. This type of problem can be solved by solar dryer. Many dryers have been developed and used to dry agricultural product in order to improve shelf life .Most of these either use expensive sources of energy such as electricity or combination of solar energy and some other form of energy which is not cost effective and dependent on regular supply of fuel.

Principally, drying requires temperature for removing moisture from product, air flow rate to remove moisture from drying chamber and optimum relative humidity within the drying chamber to allow fast drying. These all three requirements for drying can easily be achieved from solar energy. Solar drying is one of the direct applications of solar heat, which involves removal of moisture from the products through the application of solar energy. The removal of moisture requires only low temperature heating, which can be met easily by absorbing solar energy by the surface. This increases the temperature of the air inside the dryer. The moisture produced from the drying product is usually carried out along with the exhaust air. The characteristic of solar energy is good for the drying at low temperature i.e. high flow rates with low temperature rise. The intermittent nature of solar radiation can not affect the drying performance at low temperature. Further, solar energy is available at the site of use and saves transportation cost.

Solar energy is the energy emitted by the sun in the form of electromagnetic radiation. It is the most abundant, renewable, and sustainable energy resource available on Earth. Every hour, the Earth receives more energy from the sun than the entire human population consumes in a year. This makes solar energy a key candidate for solving the world’s growing energy needs while addressing environmental concerns. The solar energy reaching Earth can be harnessed and converted into useful forms of energy
Solar Photovoltaic Fencing
Solar photovoltaic fencing utilizes solar energy to provide an effective security solution, using high-voltage electric pulses to deter intruders or animals. The system operates by converting solar energy into electricity, which is then stored in a battery for later use. The battery powers an energizer that sends high-voltage pulses along the fence, creating an electric shock when an intruder touches the live wire.
System Components and Working
1. Solar Module: Converts sunlight into direct current (DC) electricity, which charges the battery.
2. Battery: Stores the energy generated by the solar panel. The 12V/100AH battery allows the system to operate even at night or during cloudy days.
3. Energizer: The energizer is the heart of the system, generating high-voltage pulses. It works by sending electrical pulses at regular intervals (usually one pulse per second) through the fence. The energizer is powered by the battery.

Energy is vital for the whole universe. Since the formation of the universe, energy acts a specific role. Steven Hawkins, George Ellis and Roger explained “The Theory of Relativity “Time and space had a finite beginning than corresponded to the origin of matter and energy from the time of BIG BANG.”. Before invention of fire, energy hovers everywhere but people did not have any knowledge about that. Living being requires energy for every day work which cells of the body provide them. Energy is also a basic requirement for the existence and development of human life. Energy plays an important role in the entire process of evolution, growth and survival of all living being and also in the social –economic development and human welfare of country. Energy is defined as the ability to work. Then we run or walk or do any type of work, we burn the energy in our body produced in cells by transforming food. Cars,planes,trolleys,ships, aeroplanes etc and all kind of machineries require energy to run. There are many sources to get energy as coal, natural oil, natural gas, wind, water, wave, sun and nuclear etc. The commercial sources of energy as fossil fuels (coal, oil, and natural gas) hydro-power and then nuclear power provide the need of energy now of the world. The demand of energy is growing an alarming rate. As for example, according to International Energy Agency the Global consumption of energy has increased from 4606 Mtoe (Million Ton Oil equivalent) in 1973 to 7287 Mtoe in 2003.

Introduction

Humans primarily get their nourishment from agriculture. According to the most recent UN estimates, the population of the globe could increase to over 9.7 billion in 2050, and to fulfill the demands of an expanding population and a rising need for food, the energy demand in the agricultural sector has dramatically expanded. However, a farm that produces food needs a steady supply of energy to run the machinery, irrigation pumps, and other devices that are often powered by fossil fuels. Because of the ongoing demand for energy, there is growing concern that these fossil fuels will also run out soon (Aroonsrimorakotet al., 2020). Additionally, other global issues like climate change, water shortage, and energy security are just a few variables affecting agricultural production that require more environmentally friendly and sustainable farming methods As a result, it is crucial to maximize land usage and increase agricultural production through the deployment of cutting-edge farming techniques and new technology for both economic effectiveness and the best possible use of the limited resources available in the form of land. There are many distinct uses for renewable energy in agricultural systems. Renewable energy sources can also be used to generate electricity for a range of agricultural tasks (Torshizi and Mighani, 2017). Renewable energy can come from a variety of sources, but solar energy is the ideal option because it can be installed practically anywhere on the field, is pollution-free, and is also the most economical. Unlike the usage of fossil fuels, using solar energy doesn’t release greenhouse gases. For remote locations with erratic access to electricity, it is the best renewable energy choice. Applications for space and water heating, greenhouse heating, solar photovoltaic systems, and water pumps for irrigation using various forms of solar energy technology (Mekhilefet al., 2013). There are numerous benefits of using solar energy technologies, such as solar panel water pumping systems, aside from being free of fuel costs, solar panels also have lower maintenance costs and require fewer replacement components than generators powered by diesel engines. In order to meet the growing demand for agricultural products from the expanding population, agriculture is a sector that aspires to accept the usage of solar energy and reaps enormous benefits from it. Therefore, solar energy technology has emerged as a solution in order to boost economic benefits to farmers and improve the environment by reducing CO2 emissions into the atmosphere, thereby addressing the issues caused by a growing population and a shrinking amount of available resources (Aroonsrimorakot and Laiphrakpam, 2019). The potential for farmers to move from using fossil fuels to using renewable alternative energy, which might lead to produce superior in both quantity and quality of food produced in various kinds of agricultural farms (Bardi et al., 2013). The issue will get worse unless the farmers change their perception about the adoption of solar energy technologies. Therefore, it is advised for farmers to employ energy-saving tools for producing crops and to maximize land by installing solar energy systems because they are practical, affordable, and useful for a variety of tasks (Duprazet al., 2011). Since many people still solely rely on fossil fuels for energy and lack access to modern energy sources, in light of this, the current study was done to assess the level of awareness and adoption of solar energy in agricultural operations.

3.1 Introduction

The sun emits electromagnetic radiation, which is referred to as solar radiation. Every location on the Earth’s surface receives some sunlight during the course of the year, but the amount of solar radiation varies. On a daily basis, we see much less energy from the sun than it emits and incident upon the earth. In an hour and a half, the amount of sunlight that reaches the surface of the earth is enough to provide enough energy for an entire year. 

7.1 Introduction

A greenhouse is quasi-permanent structure, covered with a transparent or translucent material, ranging from simple homemade designs to sophisticated pre-g\fabricated structures, wherein the environment could be modified suitable for propagation or growing of plants. Materials used to construct a greenhouse frame may be wood, bamboo and steel or even aluminum. Covering can be glass or various rigid or flexible plastic materials. Depending on the covering material, different terminology have been used in the context of greenhouse structures as mentioned below:

Glasshouse: A greenhouse with glass as the covering material is called glasshouse

Polyhouse: It is a greenhouse with polyethylene as the covering material.

Solar heat plays a pivotal role in the functioning of greenhouses, serving as a primary energy source that influences the internal climate crucial for plant growth. The absorption of solar radiation by the greenhouse covering material initiates a complex process of heat transfer, involving conduction, convection, and radiation. This solar energy, once absorbed, contributes to elevating the temperature within the greenhouse, creating a favorable environment for plants. A fundamental understanding of solar heat dynamics is essential for optimizing greenhouse design and operational efficiency.