eChapters

Leaf Relative Water Content (RWC) is a key indicator of plant water status and is used to assess water stress, physiological health, and the efficiency of water use in plants. It reflects the amount of water in the leaf relative to its maximum water capacity and is a useful measure in plant physiology and stress studies.

Materials and Equipment

• Fresh leaf samples

• Analytical balance

• Oven or drying equipment

• Desiccator

• Caliper or ruler

• Distilled water

• Petri dishes or similar containers

• Weighing boats or paper

Introduction

Carotenoids are pigments found in plants that contribute to photosynthesis and provide various health benefits. Measuring carotenoid content in leaves can help assess plant health, productivity, and the effects of environmental conditions. The determination of carotenoids typically involves extraction followed by spectrophotometric analysis.

Materials and Equipments

• Fresh leaf samples

• Acetone, hexane, or a mixture of acetone and hexane (for extraction)

• Mortar and pestle or homogenizer

• Centrifuge and centrifuge tubes

• Spectrophotometer • Volumetric flasks and pipettes • Analytical balance

Chlorophyll content serves as a vital indicator of plant health and photosynthetic efficiency, with higher levels reflecting robust photosynthesis and overall plant vigor, while lower levels may signal nutrient deficiencies, diseases, or environmental stresses. Assessing chlorophyll content helps evaluate plant productivity, as chlorophyll is essential for absorbing light and converting solar energy into chemical energy. Additionally, the chlorophyll-a to chlorophyll-b ratio provides insights into how plants adapt to various light conditions, revealing their light absorption efficiency and ability to cope with environmental changes. Measuring chlorophyll on a fresh weight, dry weight, and leaf area basis allows researchers and agronomists to gauge the effectiveness of agricultural practices such as fertilization, irrigation, and crop management strategies. It also aids in monitoring the impact of stress factors like drought, salinity, pollution, or pest attacks, which is crucial for developing strategies to enhance crop resilience.

Reagents: 80% acetone: - 80 ml acetone + 20 ml water = 100 ml

Procedure for Chlorophyll Extraction from Leaves

1. Sample Collection: Collect fresh, healthy leaves from the plant to be analyzed. Ensure that the leaves are free from dust, pests, and diseases.

2. Preparation of Leaf Samples: Rinse the leaves thoroughly with distilled water to remove any surface contaminants. Pat them dry with a clean paper towel. Weigh an exact amount (usually around 0.1-0.5 grams) of fresh leaf tissue using an analytical balance. Record the fresh weight accurately.

The Walkley-Black method is a widely used chemical procedure to estimate soil organic carbon (SOC). It involves the oxidation of organic carbon by potassium dichromate in the presence of sulfuric acid, followed by titration to determine the amount of unreacted dichromate. Here is a detailed step-by-step guide:

Materials Required

• Soil sample (air-dried and sieved through a 2 mm sieve)

• Potassium dichromate solution (1 N)

• Concentrated sulfuric acid (H2 SO4 )

• Ferrous ammonium sulfate solution (0.5 N)

• Orthophosphoric acid (H3 PO4 ) (optional)

• Diphenylamine indicator or N-phenylanthranilic acid (indicator)

• Distilled water

• Burette, pipette, and conical flasks

• Heating mantle or hot plate

Objective

To determine the pH of a soil sample, which provides insight into the soil’s acidity or alkalinity, influencing nutrient availability, microbial activity, and plant growth.

Materials Required

• Soil sample

• Distilled water

• pH meter or pH paper

• Beakers (100 mL)

• Measuring cylinder (50 mL)

• Stirring rod

• Filter paper and funnel (if needed) • Mortar and pestle (for soil grinding, if necessary)

Objective

To determine the electrical conductivity (EC) of soil, which is an indicator of the soil’s salinity and its ability to conduct electricity. This provides valuable information about the nutrient availability and potential toxicity to plants.

Materials Required

• Soil sample

• Distilled water

• Electrical conductivity meter (EC meter)

• Beakers (100 mL)

• Measuring cylinder (50 mL)

• Stirring rod

• Filter paper and funnel

• Mortar and pestle (for soil grinding, if necessary)

Sample Digestion

Dry ashing and wet oxidation are the two widely adopted methods for the release of mineral elements from plant tissues. Dry ashing is carried out usually at an ignition of 550 to 600 °C leads to loss of P and K by volatilization. Dry ashing being comparatively more time taking and also has a few drawbacks (such as S and Cl is lost by volatilization during ignition which can be prevented by adding Na2 CO3 ; a part of P and micronutrients also get occluded) is hence occasionally adopted. On the other hand, wet oxidation employs oxidizing acids like HNO3-HClO4 di-acid or HNO3-H2 SO4-HClO4 tri-acid mixture. The volatilization loss of K is prevented by the use of HClO4 and provides a clear solution while H2 SO4 helps completing oxidation. On heating HClO4 dissociates into nascent chlorine and oxygen, increasing the oxidation efficiency at high temperature. Explosion and fire may occur if there is direct contact of HClO4 with plant sample; hence the pre-digestion of samples is preferred. Digestion with HNO3-HClO4 instead of tri-acid mixture is also adopted specially when S is also to be determined in the same digest. The wet oxidation method being less time-consuming, easier and convenient is given below:

Sample Digestion

Dry ashing and wet oxidation are two widely adopted methods for releasing mineral elements from plant tissues. Dry ashing, typically conducted at temperatures between 550 and 600 °C, can lead to the loss of phosphorus (P) and potassium (K) through volatilization. This method is more time consuming and has several drawbacks, such as the volatilization of sulfur (S) and chlorine (Cl), which can be mitigated by adding sodium carbonate (Na2 CO3 ). Additionally, some phosphorus and micronutrients may become occluded during the process, making dry ashing less commonly used.

In contrast, wet oxidation employs oxidizing acids, such as a mixture of nitric acid and perchloric acid (HNO3-HClO4 ) or a tri-acid mixture of nitric acid, sulfuric acid, and perchloric acid (HNO3-H2 SO4-HClO4 ). The use of perchloric acid (HClO4 ) prevents the volatilization loss of potassium (K) and provides a clear solution, while sulfuric acid (H2 SO4 ) aids in completing the oxidation. Upon heating, perchloric acid dissociates into nascent chlorine and oxygen, enhancing the oxidation efficiency at high temperatures. However, direct contact between perchloric acid and plant samples can lead to explosions and f ires; thus, pre-digestion of samples is preferred.

Nitrogen, a key component of organic materials like proteins, is analyzed using the Kjeldahl method, which is the global standard for determining protein content in various substances, including human and animal foods, fertilizers, wastewater, and fossil fuels. The Kjeldahl method involves three main steps:

A. Digestion

B. Distillation

C. Titration

Nitrogen, making up 1-4% of a plant’s dry weight, is vital for synthesizing chlorophyll, proteins, and other key compounds. Plants with high nitrogen levels turn dark green due to increased chlorophyll. Understanding nitrogen content in plant tissues is crucial for diagnosing deficiencies or toxicity and for effective nutrient management to improve crop production.

Determining the nitrogen content in plants is crucial for understanding plant nutrition, assessing the efficiency of fertilizer use, and making informed decisions in agricultural practices. Various methods can be used to determine nitrogen in plant tissues, with the most common ones being the Kjeldahl method, the Dumas method, and near-infrared reflectance spectroscopy (NIRS).

The Dumas combustion method, named after the renowned French chemist Jean-Baptiste Dumas, is a widely recognized analytical technique employed in the determination of the elemental composition of organic compounds. This method involves the complete combustion of a sample in an oxygen rich environment, followed by the separation and subsequent analysis of the resulting combustion products.

Principle

The Dumas combustion method involves the complete combustion of a sample in the presence of excess oxygen. The nitrogen present in the organic compound is converted into nitrogen gas (N2 ), which is then measured quantitatively. The process can be summarized as follows:

i. Combustion: The sample is combusted at high temperatures (typically around 900-1000°C) in the presence of oxygen. This results in the conversion of all organic material into carbon dioxide (CO2 ), water (H2 O), and nitrogen gas (N2 ).

ii. Removal of Interfering Gases: The combustion products are passed through various reagents to remove interfering gases such as CO2 and H2 O.

iii. Detection of Nitrogen: The nitrogen gas is then measured, often using a thermal conductivity detector (TCD) or another suitable detection method.

Assessment of a soil’s fertility status involves an estimation of its available nutrient status i.e., the portion or amount of nutrient directly available in soil for subsequent uptake by crop plant. This exercise commonly referred to as soil testing and is used to arrive at optimum fertilizer application ratio. The need for estimation of available nutrient arises because only a small fraction of what the soil contains is the total nutrient content of the soil. Soil test is calibrated by correlating them with crop response and the result from the basis for making fertilizer recommendations.

Estimation of nutrient contents and forms in materials that are involved in nutrient supply and dynamics is a conical step towards planning scientific nutrient management. In this content, both soil and plant testing information come out of the interpretation of analysis assumes a greater value when their concentrations and amounts can relate to soil fertility, nutrient availability, plant growth, yield and quality of the crop produce.

The seed yield, along with the rate of application and uptake of nutrients, is used to determine the following parameters for nitrogen or other nutrients:

Partial Factor Productivity (PFP) (kg seed/kg N applied): Partial Factor Productivity (PFP) is a measure used in agriculture to assess the efficiency of nutrient use, particularly nitrogen or other essential nutrients, in crop production. It is calculated as the ratio of the seed yield to the rate of nutrient application. The formula for PFP is:

*A higher PFP value indicates greater efficiency, meaning that more crop yield is produced per unit of nutrient applied. This is desirable as it implies that the nutrient is being used more effectively by the crop.

Agronomic Efficiency (AE) (kg seed/kg N applied): Agronomic Efficiency is a measure used to evaluate the effectiveness of nutrient application in increasing crop yield. It specifically assesses the yield gain per unit of nutrient applied. The formula for AE is:

The growth and productivity of crops depend on various factors, with the nutrient content of plant parts like leaves and stems playing a crucial role. These parts are often used as indicators to assess the nutrient status of plants. Each crop requires essential elements at specific concentrations during different growth stages, known as ‘critical levels’. When the nutrient content falls below these critical levels, plants may display symptoms of deficiency.

Nutrient requirements and availability can be evaluated through: i) plant diagnosis, ii) soil analysis, and iii) plant analysis using qualitative or quantitative methods. By conducting these tests, necessary nutrients can be identified and applied to crops to sustain growth and correct deficiencies. While rapid tissue tests offer quick solutions for nutritional problems, quantitative estimation of both plant and soil nutrient concentrations is more economical and provides a long-term strategy for managing nutritional issues. Implementing quantitative estimation allows for informed application of fertilizers, whether as basal or foliar, thus addressing deficiencies effectively and ensuring sustainable crop growth.

Introduction

The physiological disorder of a mineral nutrient is entirely contingent upon its function within the plant body. Inadequate or excessive supply of any essential element can result in metabolic disruptions, influencing the activities of enzymes, rates of metabolic reactions, and concentrations of metabolites. Alongside alterations in metabolic patterns, severe deficiencies of specific essential elements also give rise to distinctive effects in leaves, stems, roots, blossoms, and fruits.

A. Nitrogen

Functions: Nitrogen is essential for plants, playing crucial roles in protein synthesis, nucleic acid formation, and chlorophyll synthesis. It is a key component of enzymes, contributing to various metabolic processes. Nitrogen also supports root development, cell structure, and the synthesis of secondary metabolites. Striking a balance in nitrogen levels is vital for maintaining plant health and ensuring optimal growth and productivity. Effective nitrogen management is essential for sustainable agriculture and overall ecosystem well-being.

In the realm of natural elements, there exist approximately one hundred and three distinct elements. Among them, nearly ninety elements are absorbed by plants. To differentiate essential elements from those that plants can assimilate but are not vital, Arnon (1954) established the following criteria:

1. The plant must be incapable of normal growth or completing its life cycle in the absence of the element

2. The element is specific and irreplaceable by another

3. The element directly participates in plant metabolism

By applying these criteria, molybdenum and chlorine are not deemed essential, even though they serve a functional role in plant metabolism. This is because they can be substituted by vanadium and halides, respectively. Subsequently, D. J. Nicholas refined the definition of essential elements, replacing the term “functional or metabolic nutrient” to encompass any mineral element that contributes to plant metabolism, regardless of whether its action is specific.

There is no terminal of any kind of research, rather they presence a static snap of the gamut of ecological dynamics and functions.

The following scopes for future research

• To construct modelling on resilience, beyond agriculture like livestock f ishery, forestry.

• To create new Algorithm of prediction in ecological behaviour and dynamics

• Gender and economic factors in resilience study and analysis

• Ecological resilience in different agro climatic zones covering coastal ecosystem, Himalayan ecosystem red lateritic ecosystem etc

• Policy research in ensuring and intriguing ecological resilience as well as social resilience on the common platform of production behaviour

• Importance of ecological resilience in the perspective of climate change and global warming

7.1 Summary

Never ever in the annals of human civilization, the importance of ecological resilience has become so important and imperative as we are perceiving now. Both the need and greed of food economics have driven the resource bases of our ecosystem, to a dilapidated and fragile status. By 2050 the world’s population will touch close to 9.5 billion and we have to scale up our food production 60% more then what it is right now. In India by 2040, we have to cross 450 million tons of our targeted food production to keep rhythm with population growth. By 2035 we are going to cross the population of China. Understanding the cascade of risks for climate change, as well as the vulnerabilities to these risks, is key to frame ways to adapt. Reducing vulnerabilities is key to reducing the net impacts on food security and nutrition and also to reducing long-term effects. Increasing resilience of food security in the face of climate change calls for multiple interventions, from social protection to agricultural practices and risk management..

When population pressure is soaring up, the need to produce more food from less and less available land and water, the issues of ecological resilience are coming up more swashbuckling and humongous. The aftermath of green revolution has contributed to achievement in food security on one hand, the other hand water has been contaminated and depleted, soil has been eroded with a sharp decline of organic carbon. We are losing 15 tons of topsoil per hectare per year and inviting a disruptive agro-ecosystem, the syndrome of which are quite vivid and prominent.

6.1. Data Interpretation and Visualization of West Bengal

Any kind of production management system or decision-making process is being organised in social ecology. No variable cannot behave discrete or free without having any kind of influence as well as impact from the vary operating ecosystem. That is how it is imperative to know and visualize the basic features in terms of its distributive characters. The distribution of features in variables through this networking and interactions ultimately contribute to a holistic visualization of social ecologization under study.

Table 6.1.1 represents the distribution of variables in terms of range i.e. maximum and minimum values, mean, standard deviation and coefficient of variation for Terai Zone, Old Alluvial Zone and New Alluvial Zone of West Bengal.

The average age (x1) of the respondent stands at 49.02. It denotes that so far as responsibility of agriculture and age base livelihood runs at the population so far as the respondent under study is peaks are at the hands of farmers approaching or passing through old ages. On the contrary the absence of young population or withdrawal of young age farmers from agriculture have got a serious implecation near and far. The cv value runs at 25.78 per cent to indicate that the distribution of variable is highly consistant.

The average of functional education (x2) of the respondent stands at 8.20.The variable education charecterization the social ecology speaks that the most of the respondents are having mid level school education.So, this has got spil over effect on the function and operation of other variables i.e. precisely the perception variables.The cv value stands at 43.69 per cent that’s good enough to infer that the distribution of the variable is highly consistent.

5.1 Locale of Research

Based on the All-India assessment report regarding Climate Vulnerability Assessment for Adaptation Planning in India Using a Common Framework which identifies the most vulnerable states and districts in India with respect to current climate risk and the main drivers of vulnerability, the present study has been conducted in two relatively highly vulnerable states of India namely West Bengal (Vulnerability Indices:0.592) and Jharkhand (Vulnerability Indices: 0.674). It specifically comes under Agro-climatic zone III (Lower Gangetic plain region) and Agro-climatic zone VII (Eastern plateau and hilly region) respectively.

On the basis of Vulnerability Indices (Vis) different district of West Bengal classified into three categories i.e. relatively high vulnerability (0.59-0.69), moderate vulnerability (0.49 -0.59), and relatively low vulnerability (0.38- 0.49). Two districts, Malda (VIs:0.690) and Jalpaiguri (VIs:0.627) from highly vulnerable and three district Murshidabad (VIs:0.524), Dakshin Dinajpur (VIs:0.523) and Burdwan (VIs:0.497) from moderate vulnerable category were selected purposively for the present study. For satisfying the purposes three agroclimatic zones of the West Bengal, viz. Terai Zone (Jalpaigudi), Old Alluvial Zone (Murshidabad and Dakshin Dinajpur) and New Alluvial Zone (Burdwan) districts were taken into account for the assessment. Twenty respondents of two Villages from each Block i.e., Alipurduar-I of Jalpaigudi, Hilli and Gangarampur of Dakshin Dinajpur, Old Malda of Murshidabad and Barabani of East Burdwan were purposively picked for the research study.

In any social science research, it is hardly possible to conceptualize and perceive the data and interpret the data more accurately until and unless a clear understanding of the characteristics in the area and attitude or the behavior of people is at commend of the interpreter who intends to unveil an understanding of the implication and behavioral complexes of the individual who live in the area under reference and form a representative part of the larger community. The socio-demographic background of the local people in a rural setting has been critically administered in this section. A research setting is a surrounding in which input and elements of research are contextually imbibed, interactive and mutually contributive to the system performance. Research setting is immensely important in the sense because it is characterizing and influencing the interplays of different factors and components. Besides the investigators must also have the basic knowledge about the socio demographic background of the people so as to have an easy understanding of their knowledge, attitude and behavior.

Research setting refers to the detail information of an area where the study has been conducted. The study area, generally comprises of a particular geographical area viz. a state, district, block, or gram panchayat area selected according to the convenience of the investigator who possess adequate knowledge regarding the location, communication facility etc. of the locality so that he/she can easily approach each and every corner of the area for data collection. Here. in this study the data collection was done mostly over telephone based on the interview schedule due to Covid-19 pandemic situation.

3.1 Conceptual Framework

Aconceptual framework is an analytical tool that is used to get a comprehensive understanding of the study. It embodies the specific direction by which the research will have to be undertaken. It is generally constructed to provide the researcher the element ofattainable and researchable problems and ideas supported by methodology, design, prospective analysis and empirical conclusion. The conceptual framework is often called as the research paradigm.

The subject matter of the present research is Resilience and productivity of agriculture in different social-ecology: the farmers’ perception, status and interpretation. It is expected that the terminologies and concepts used to frame up the topic need to undergo brief explanation for the better understanding of its meaning.

Resilience: Resilience is about anticipating, planning and reducing disaster risk to effectively protect persons, communities and countries, their livelihoods, health, cultural heritage, socio-economic assets and ecosystems. The ideas of ‘bounce back’, ‘spring forward’ and ‘build back better’ are often used in the context of resilience.

Productivity: Productivity is commonly defined as a ratio between the output volume and the volume of inputs. It measures how efficiently production inputs, are being used in an economy to produce a given level of output.

Agriculture: The word agriculture derives from the Latin ager (field) and colo (cultivate) signifying, when combined, the Latin agricultura: field or land tillage. But the word has come to subsume a very wide spectrum of activities that are integral to agriculture and have their own descriptive terms, such as cultivation, domestication, horticulture, arboriculture, and vegeculture, as well as forms of livestock management such as mixed crop-livestock farming, pastoralism, and transhumance. The Oxford English Dictionary (1971) defines agriculture as “The science and art of cultivating the soil, including the allied pursuits of gathering in the crops and rearing livestock; tillage, husbandry, farming.”

This chapter is an extensive survey of all past studies relevant to the field of investigation which gives a knowledge of what others have found out in the related f ield of study. In any scientific investigation or research a comprehensive presentation of review of literature is a statutory requirement. Its main functions are to develop a better understanding of the problem to be investigated, delineate a new area of study and avoid unnecessary duplication, decide on the tools and techniques to be adopted including developing some new ones, also to relate the present study with the previous ones by finding out the areas of agreement and disagreement.

The review of literature of the present study is based on the major concepts related to the f ield of investigation. As direct references on all the item are not in abundance, certain specific references along with some indirect references have been incorporated in this chapter for the purpose of meaningful use.

Review of literature has been organized with a view to provide hard evidences as to clinically justify the reasons, logic, and contemplation leading to heuristically infer the different echelons of resilience issues.This is also catered to isolate the apparently less attempted genre of resilience study and analysis. Climate change, uncertainty, decline of soil organic carbon, fatigued genes on land, loss of biodiversity and fragile ecology of society have only been some of myriad of factors causing the loss of resilience, from ecology and from society as well.

1.1. Background

Once this beautiful planet conceived human civilization with the glory of motherhood, the birds kept on twittering in an ecstasy of joy and freedom; the ripples of pristine rivers, blue and giggling, offered shelter to silvery fishes and pink Amazon Lilies! But human greed has defeated its own needs. So, what had been a means to survive now has turned into tools to triumph, rather, a weapon to destroy her own creation. By this time, we have transformed fertile lands into a barren Arizona, deep forests into a nasty slums and blue rivers into a filthy stream, called Yamuna.

The advent of the Anthropocene, implies that an unprecedented era of human impact on the natural environment, is now so large that the Earth has entered a new geological epoch; it is leaving the Holocene, the environment within which human societies themselves have developed (Gornish and dos Santos, 2016; Reynolds, 2021). Climate change is a prominent sign of human- driven changes to the global environment. There is every reason to be alarmed about anthropogenic climate change, pollution, and biodiversity loss, all of which have been accelerating in recent decades and do pose “existential crisis” (Díaz et al., 2020; Abhilash et al., 2021). Sixth Assessment Report of Intergovernmental Panel on Climate Change (IPCC) released on February 28, 2022, paints a troubling picture as limiting global warming to 1.5oC (a global target in the Paris Climate Agreement) is not safe for all. If warming exceeds 1.5oC, even temporarily, much more severe, often irreversible effects of climate change will occur, land and ocean temperature change, sea level rise and ocean acidification, loss of Arctic Sea ice and ice sheets, stronger storms, longer heatwaves and droughts, abrupt precipitation mainly intensity and seasonal distribution, thawing permafrost and more (IPCC, 2013). On the basis of the Sixth Assessment UN Secretary-General António Guterres said “The alarm bells are deafening, and the evidence is irrefutable: greenhouse gas emissions from fossil fuel burning and deforestation are choking our planet and putting billions of people at immediate risk.” According to the United Nations (2015), there are still 836 million people in the world living in extreme poverty (less than USD,1.25/ day). And according to the International Fund for Agricultural Development (IFAD), at least 70% of the very poor live in rural areas, most of them depending partly or completely on agriculture for their livelihoods. It is estimated that 500 million smallholder farms in the developing world are supporting almost 2 billion people, and in Asia and sub-Saharan Africa these small farms produce about 80 percent of the food consumed (IFAD, 2011). The rural poor often depend partly on forests for their livelihoods (World Bank, 2002). It is estimated that between 660 and 820 million people (workers and their families) depend totally or partly on fisheries, aquaculture and related industries as a source of income and support (HLPE, 2014).

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,

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.

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.

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.

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.