eChapters

Introduction to GIS

QGIS (Quantum GIS) is an open-source Geographic Information System (GIS) software has been used to showcase various exercises pertaining to viewing, editing, analyzing, and printing of the geospatial data. QGIS helps to allow the users to easily access and manage geographic data stored in folders on local disks or relational databases available on the user’s network. QGIS supports raster, vector, and mesh layers. QGIS also allows using data from external sources with the help of web services such as Web Map Service (WMS) and Web Feature Service. QGIS is a constantly developing software as anyone can add new features or update existing tools. Newer versions of QGIS are frequently released on the official website. It is a cross-platform software that can be installed in Windows, Linux, and MacOS.

The native and applied organic matter play an important role in terms of nutrient adsorption , nutrient mobility and microbial habitat on soil. The dominant ions present in soil under a particular agro-ecological situation may or may not be available to the growing plants due to the presence of organic matter. The binding energy and the stability of the organo-metal complexation would play an important role in availability of nutrients to the plants. The organo-metal complexation reaction depends on the nature of the ionic species (ionic/non ionic) present in soil. The organic fractions (Humic acid/Fulvic acid) react with metal ions present in soil to form complexes which may be stable or unstable depending upon the molecular arrangement and degree of coiling of humic/fulvic substances. The surface charge density on clay and soil pH also play an important role to determine the order of stability of different nutrients (macro/micro) in soil.

Understanding the chemistry of submerged soil in the field of Geology, Pedology, Agriculture and other allied sectors draws attention to the research on characteristic changes in soil under submergence. It has been reported that, about 72% of the earth’s surface is covered by submerged soils or sediments . Rice plants have unique adaptation capability to grow under submerged soil and in any type of soil (acid/alkaline) condition or land situation (upland/lowland). The knowledge on changes of important physical, chemical and biological properties under submergence have important role to play in understanding the mechanisms of availability of nutrients to the plants and sustainability of the crop during its growing period.

9.0 Submerged Soil

The soils which are saturated with water for a longer period of time in a year to make the soil a distinctive gley horizons resulting from oxidation-reduction processes are called submerged soil. About 72% of the earth’s surface is covered with soil –submergence or sediments.

Nutrient adsorption in soil is one of the important phenomena in terms of nutrient availability to plants. Due to the nutrient fixation of the added nutrients supplied through fertilizers or manures may result the increase in cost of production due to the non-availability of the added nutrients at the optimum level to the plants. Hence, management options are required to release the sorbed nutrients from soil for better availability to the plants. The ion-fixation is driven by physico-chemical and biological processes and varies under agro ecological situations. The chemistry of ion fixation in the form of specific or non-specific adsorption on soil colloids will help understanding the bonding and adsorption reactions of ions in the soil.

8.0 What is fixation?

Fixation of plant nutrients in soil may be defined as the process, where readily soluble plant nutrients are transformed into less soluble forms by physical or chemical reaction with organic or inorganic compounds and thus restricting the mobility of ions in soil that leads to the decrease in availability to the plants. There are two kinds of fixation in general, viz; cation (N, K, Fe, Mn, Cu, Zn, Ca,Mg etc.) and anion (P, B, Mo etc.) in soils. The fixation of ions in soil is governed by important physical and chemical parameters of soil based on which the available pools of nutrients for plants may be determined.

The soil acidity and alkalinity are major driving forces in regard to the mobility of plant nutrients from soil to plants. The extreme acidity or alkalinity cause damage to the crops and thus yield is affected. Correction of soil acidity or alkalinity depend upon the pH of the soil and its previous management options. Application of fertilizer in soil may be one of the factors affecting soil conditions. Exchangeable and soluble iron and aluminium ions and their hydroxy ion species may contribute hydrolysis to release H+ ions to the soil solution. The soluble salts of carbonate and bicarbonates also develop salinity in soils.

7.0 Soil reactions

Soil reaction is an indication of the acidity or alkalinity of soil and is measured in pH . The pH scale ranges from 0 to 14 with pH 7 as the neutral point. When the amount of active hydrogen ions in the soil solution increases the soil pH decreases and thus becoming more acidic in reaction. One of the outstanding physiological characteristics of the soil solution is its reaction. Soil reaction can influence the physico-chemical properties of soil which can regulate the growth and activity of plant and soil organisms associated with it.

The exchange of ions (cations or anions) are important phenomena in soil for the growth and nutrition of the crops. The oppositely charged ions are being adsorbed by the clay colloids which are subjected to be released or exchanged reversibly from the soil solution. The participating ions in the exchange process are called exchangeable or counter ions. The activity of ions depends on the pH of the soil. Hence, factors like, soil texture, organic matter, concentration of ions could govern the ion exchange phenomena in soil.

6.0 Ion Exchange

Ion exchange is a reversible process where exchange of ions are possible between the two electrolytes or between an electrolyte solution and a complex. The ion exchange processes help in purification, separation, and decontamination of aqueous and other ion-containing solutions. The ion-exchange resins (functionalized porous or gel polymer), zeolites, montmorillonite, clay and soil humus are considered as typical ion exchangers which are either cation exchangers [exchanging positively charged ions (cations)], or anion exchangers [which can exchange negatively charged ions (anions)].

Soil colloidal substances are composed of very fine particles (< 0.002 mm diameter) that undergoes two phase system in a heterogenous manner, where, one phase (disperse phase) is disperse in a fine state of subdivision in another medium called dispersion medium. The soil colloidal properties are affected by the physico-chemical and biological parameters of soils. The availability of plant nutrients are governed mostly by the surface charge characteristics of clay colloids.

5.0 Soil Colloids

Soil colloids being one of the active constituents determine the physical and chemical properties of the soil with the diameter ranging from 1 μm to 2 μm. The origin of the particles may be organic and inorganic constituents.

4.0 Soil organic Matter

The soil organic matter (SOM) is a storehouse of multi-nutrient elements, composed mainly of carbon, hydrogen and oxygen and small amounts of other elements like nitrogen, phosphorous, sulphur, potassium, calcium , magnesium and organic residues coming out from the decomposed plant or animal products (Figure 4.1). The SOM may have the recently incorporated materials or age-old decomposed materials or with living flora or fauna in the organic matrix. Soil organic matter is one of the important components determining soil quality indices and also for enriching the fertility status of soil for production maximization. The nutrient retention capacity , water holding capacity, degradation of pollutant elements, carbon sequestration, soil structure and aggregate stability are affected by the presence of SOM.

The plant can absorb more than sixty elements as revealed from the plant tissue analysis, still a few elements is considered essential for the growth and nutrition of the plants. The deficiency of any one of the essential elements can stop completing the life cycle of the plants which is reflected on the yield of the crop. The growth of the plant which is expressed in terms of dry weight, length ,diameter etc. are interlinked with the plant available nutrients of soils.

3.1 Essential Nutrients

The essential elements are those elements which are required for growth and nutrition of the plants. There are 17 elements known to be essential nutrients for plants. The essential elements are classified as micro and macronutrients depending upon the requirement of the crop. Among the naturally occurring elements, eighteen elements are considered essential to plants. These are: C, H, O, N, P, K, Ca, Mg, S, Fe, Mn, Zn, Cu, B, Mo, Cl, Ni, Co. The elements which are found in different sources are required to be in available forms (Table 3.1) for growth and nutrition of the plants.

Soil is one of the major platforms on which life sustains. Soil, the product of weathering, covers the earth’s surface. Soil is the medium of plant growth and thus it requires proper attention for better crop yield. The land is the constituent of soil, vegetation, physico-chemical and biological attributes affecting its usages. The soil may act as a sink or source for the elements and other materials. Hence, it requires to understand the various components to facilitate management options for improving the fertility status of soil.

2.0 Soil

The soil is a natural dynamic body on which plant grows. It is a complex mixtures of minerals, water, air, organic matter and microorganisms. Besides, there exist an unconsolidated mineral or organic material on the surface of the earth and thus becomes a natural medium for the growth and nutrition of the plants.

The knowledge on fundamental principle of chemistry is important to understand and examine the mechanisms of reactions to form products. The chemistry of soil processes will also help understanding the correlation between the basic and applied sciences for achieving the sustainable ecosystem in the environment. The formation and stability of bonds, thermodynamic principles, radioactivity, coordination number etc. are essential to solve the on-going interactions in nature. The structure of atomic models, valence and equivalent weight, creating elementary particles, quarks, neutrinos, bosons are some of the important arena where fundamental study and research can be explored for the basic and strategic ideas. Hence, it is very much essential to apprehend the concept of physical chemistry, soil chemistry and geochemistry to correlate with the definitions of chemistry for understanding the source/sink properties of soils for nutrient adsorption and release characteristics.

Depending on various findings of the study, the present section put forwards some of the policies that can be implemented for using population mobility as a tool of economic development in both rural and urban areas.

• Steps must be taken to boost up the urban services sector as it is the most attractive sector for urban in-migrants. Pro-migrant policies including some economic and social benefits e.g. free health insurance, employees’ provident fund, grater loan facilities at lower rate etc. must be provided to the migrants so that it helps the labors as well as self-employed persons of urban informal sector.

6.1 Summary

The study analyzed the economics of family migration decision and its relationship with urban informal sector and agricultural efficiency. The study is mainly based on primary survey, though various secondary data Sources have been consulted. The primary survey has been conducted in Birbhum district of West Bengal covering 300 households with equal share of rural and urban households. The selection of the district is mainly guided by the dominance of rural-urban migration and the wide prevalence of both agricultural and non-agricultural activities. By tracing the reasons of migration across the states of India, the study provides a vivid picture of the rural-urban migration in West Bengal and it is associated linkages with agricultural efficiency and urban informal sector. Sophisticated statistical and econometric tools have been utilized to justify the economic explanation of rural urban migration in West Bengal.

Descriptive Statistics of Independent Variable With Respect to Minimum, Maximum, Range, Mean, Standard Deviation of Values, Variance, and Coefficient of Variance:

Results: The variable age (x1 ) having the range between 20 to 62. So, the mean of the age (x1 ) variable is 38.64. Similarly, the other variables education (x2 ), family size (x3 ), family income (x4 ), risk factor (x5 ), management factor (x6 ), natural calamities (x7 ), employment status (x8 ), expenditure (x9 ), push factor (x10 ), pull factors (x11 ) have the mean 5.220, 4.720, 1.270, 0.505, 4.790, 3.875, 4.809, 5.655, 2.226, 5.613 respectively. Here, we see that distribution of variables education (x2 ) and push factor (x10 ) among the respondents are moderately consistent and residual distribution of variables among the respondents are highly consistent.

Local of the study: Migration, from very beginning of civilization, has been one of the most important phenomenons in population distribution across the world. As a result, it has been a major focus of both sociological as well as demographical studies around the world. Though migration theories get its root from the famous article of Ravenstein (1889) but most of the modern migration studies so far have centered around the conventional approach of migration as one of the cornerstones known as the Harris-Todaro Model of Migration Harris and Todaro (1970), which is considered as one of the cornerstones of migration studies. This model dealt with the migration decision of an individual of a family, keeping apart the role of family as a whole. The main approach of this model was some kind of cost-benefit type of assessment in undertaking migration decision. Here the potential migrant was to analyze the expected return that he/she may receive after migrating and the cost that to be borne in the process. If the net return is found to be positive then there is every chance that the concerned person will migrate and more from the place of origin to the place of destinations. The major attack that this approach received is that it gave individual the highest importance in migration decision ignoring the role of ‘family’ and thus the migration studies until recently were partial in nature.

3.1 Introduction

In developing and in semi-developed countries, rural-urban migration is driven by the uneven distribution of employment, income-opportunities etc. (Skeldon, 1990). Rapid population growth, especially in rural areas, provides an important demographic backdrop to these rural-urban population shifts. Given the growing and well-known difficulties that are faced by the overall Indian population in f inding productive employment, it is important to study the characteristics of labors that migrate from rural-urban areas. Under this backdrop, attempts have been made in this study to examine the nature, pattern and determinants of rural urban migration and the spread of urban informal sector and the likely impact of rural-urban migration on agricultural productivity and efficiency.

The economics of migration has drawn attention of many economists and social scientists over the years. Decision making in migration has certain inherent complexities as it takes into account the characteristics of both areas of origin and areas of destinations. Similarly it involves the status of agricultural productivity and efficiency, extant of urban informal sector along with various other amenities available in the destination urban areas. The subject of rural-urban migration and its inter-linkage with urban informal market and agricultural productivity have received considerable attention in theoretical framework as well as in empirical research. Among these vast literatures, the study has reviewed some of them and made a synoptic assessment on these issues in general. Moreover an attempt has been made to review the existing literature on rural-urban migration in West Bengal.

2.1 Migration Decision Making

Migration decision can be two types: individual decision making and family decision making. These two sets of migration decision involve distinctly different sets of factors. Stark (1991) has rightly pointed out that “….the family, should not be treated as if it were an individual”. So there are differences between individual migration decision and family migration decision. Migration decision depends on a host of factors, some are economic, some are demographic and some are sociological in nature. However, individual and family migration decisions are determined by two distinctly different sets of factors.

Migration is inevitable in the process of economic development (Afsar, 2003; Ballard, 2005). There exists a two-way causation between migration and economic development. Migration induces economic development while economic development induces further migration. Migration can be two types: international migration and internal migration. International migration deals with migration across the countries of the world, while internal migration deals with migration within the national boundary of a country (Zohry, 2005). There are four streams of internal migration which are rural-rural, rural-urban, urban-rural, and urban-urban. Among these four streams, rural-urban migration has certain distinct characteristics which affect developmental aspect of both places involved namely, place of origin and place of origin and place of destination. It is well known that developmental disparities between rural and urban triggers rural-urban migration. People generally migrate from less developed rural countryside to more developed urban centers they left farming and engaged in modern works which are more profitable and low risk oriented (Bhattacharya, 1993; de Haan, 1997). The impact of migration can be assessed in several ways; therefore welfare impacts, social impacts, economic impacts etc. For example, remittance send by the urban migrants to their native villages help them to evade poverty; increase consumption; invest more in agriculture, education, health. Remittances have certain social impacts as well.

In meteorology, we often use some of the physical parameters to explain the physical processes taking place in the atmosphere. These parameters must have already appeared in the earlier chapters. However, these are given in this chapter to enable the readers to get acquainted once again.

16.1 Momentum

Momentum is defined as the product of mass and its velocity. In S.I. system units mass is expressed in kilograms and velocity in meters per second.

Momentum = Mass x Velocity

Units for momentum (S.I. system) = kg. m/sec

In C.G.S. System, mass is expressed in grams and velocity in cm/sec.

Units for momentum (C.G.S System) = gm.cm/sec

From the beginning of 18th century, the human activities started increasing gradually. Industrialization, increased use of petroleum products, deforestation, mining and increased use of chemicals have contributed to the pollution of natural resource base. The proportion of gases such as carbon dioxide, nitrous oxide, methane etc started increasing in the atmosphere and more heat is getting trapped in the atmosphere leading to rise in atmospheric temperatures (Fig. 15.1).

The changes in atmosphere temperatures have led to changes in weather patterns. This changes in weather pattern triggered extreme situations like heat wave, cold wave, severe cyclonic activity, strong winds and hail storms, f loods and droughts of greater intensity creating new records.

According to Thornthwaite’s method of climatic classification, six major types of climates exist in India (Fig. 14.1) as stated below:

14.1 Perhumid Regions of India (A)

These regions receive rainfall of more than 2500 mm and consist of Konkan region along Western Ghats, Kerala and most parts of northeast India covering Assam, Meghalaya, Arunachal Pradesh and Tripura etc.

14.2 Humid Regions of India (B)

These regions receive annual rainfall ranging from 2000-2500 mm and are found in areas adjoining perhumid climate.

India is one of the unique countries in the world with great diversity in climate. The annual rainfall varies from about 180 mm in North western part of India to almost 11,777 mm at Cherrapunji in Meghalaya. For a considerable amount of time, Cherrapunji had occupied the position of wettest place in India. However, off late, observations revealed that it is Mawsynram which receives the maximum amount of annual rainfall. Hence, Mawsynram with 11,872 mm annual rainfall is the wettest place in India. Both the places-Mawsynram and Cherrapunji-are located within 16 kilometers from each other in the East Khasi Hills district of Meghalaya. The maximum temperature at Churu in western Rajasthan is 50ºC and the lowest minimum temperature at Leh in Ladakh region is as low as -35ºC. In view of such great diversity in the distribution of rainfall and temperature in the country, it is necessary to have clear understanding on regional, seasonal and diurnal variation in different weather parameters (Fig. 13.1).

The weather parameters that may occur outside India will also play a dominant role on weather conditions in India. Such weather parameters are called as global weather parameters and were found to play very important role on weather even in most parts of the world. During normal conditions in the Pacific Ocean, trade winds blow west along the equator, taking warm water from South America towards Asia. To replace that warm water, cold water rises from the depths-a process called upwelling. These global parameters are popularly known as El Ni?o, La Ni?a, Southern Oscillation, and ENSO (combination of El Ni?o and Southern Oscillation).

Whenever the daily maximum temperature exceeds more than average values during summer season the heat wave will occur. Similarly, whenever the daily minimum temperature falls below the average values cold wave will occur. The India Meteorological department has developed the criteria to identify the occurrence the heat waves and cold waves.

11.1 Heat Waves

Heat wave is defined as the condition when the daily maximum temperature is 45ºC or more. Based on departure from normal daily maximum temperature of 40ºC onwards the heat waves are defined as follows:

Drought is a situation when the demand for water is much greater than the availability of water. Drought is a creeping phenomenon and it is experienced only after it has set in. The scarcity of water compared to demand will have greater impact on every activity of human life including failure of crops, food shortages, decline in ground water table, drying tanks, lakes or reservoirs, acute shortage of drinking water for humans and livestock shortage for cattle etc.

Drought will have very serious impact on economy of households as well as that of nation. There are five different types of droughts depending upon the nature of shortage of water

10.1 Meteorological Drought

Meteorological drought occurs when the water received through rainfall during a given period is much less than long period average rainfall of the area. The meteorological drought is associated with either failure of rain or due to long gap between the successive rainfall events. In India, meteorological drought occurs due to failure of south west monsoon or long breaks in south west monsoon rainfall. In Tamil Nadu the drought occurs due to failure of north east monsoon rainfall during months of October to December.

The division of earth’s climates into worldwide system of contiguous regions, each one of which is defined by relative homogeneity of the climatic elements (Fig. 9.1)

9.1 Koppen’s Classification

Koppen’s climatic classification describes 5 major groups of climate A, B, C, D and E which are sub-divided into a total of 14 individual climate types, along with a special category of Highland (H) climate.

A - Tropical: Average temperature of coldest month is 18°C or more.

B - Dry climate: Potential evapotranspiration exceeds precipitation.

C - Warm temperature: The average temperature of the coldest month (of the middle latitudes) is higher than -3°C but below 18°C.

The general circulation of the atmosphere explains the formation of pressure belts and wind systems in the earth’s atmosphere. It is known that the earth receives more solar radiation near the equator and gets heated more. Consequently, the air gets heated more and rises vertically upwards. As there is more convection of the air near the equator, the atmospheric pressure will be less. The warm air which moves upwards up to a height about 14 km near the equator gets cooled and move towards the poles.

The upper air gets gradually cooled when it reaches a latitude of 30°N in the northern hemisphere and 30°S in the southern hemisphere. At about 30°latitude the cold air descends to the earth’s surface. Some of the cold air after descending to earth’s surface moves towards the equator. The circulation of air between the equator and 30°N or 30°S latitudes is called Hadley cells (Fig. 8.1).

The winds blowing from 30° latitude towards the equator at surface level are called trade winds. These trade winds which move towards the equator in both northern hemisphere and southern hemisphere converge near the equator and the zone of the convergence of these winds is called Inter Tropical Zone of Convergence. As the convergence of air takes place, due to convection of heat as a result of high temperatures leads to vertical lifting of moist air. Therefore, the Equatorial regions receive more rainfall and there are tropical forests in this region.

Clouds play very important role on weather and climate. The formation of clouds takes place when water condenses in the sky. Clouds are visible accumulation of tiny water droplets and ice crystals in the Earth’s atmosphere. The moisture is always present in the atmosphere though it may not be visible. Clouds form when air becomes cooler until the water vapour present in it condenses to liquid form. The condensation over oceans occurs around solid particles like salt, dust, smoke etc. suspended in the atmosphere. The type of clouds depends upon temperature and wind. The clouds are classified based on physical appearance and the height at which clouds are formed (Fig. 7.1).

Clouds play very important role on weather and climate. The formation of clouds takes place when water condenses in the sky. Clouds are visible accumulation of tiny water droplets and ice crystals in the Earth’s atmosphere. The moisture is always present in the atmosphere though it may not be visible. Clouds form when air becomes cooler until the water vapour present in it condenses to liquid form. The condensation over oceans occurs around solid particles like salt, dust, smoke etc. suspended in the atmosphere. The type of clouds depends upon temperature and wind. The clouds are classified based on physical appearance and the height at which clouds are formed (Fig. 7.1).

The mass of a body is usually defined as the material content of the body whereas the weight of the body is defined as the force with which the body is attracted towards the earth due to gravity. Therefore, the weight of a body is the product of its mass and acceleration due to gravity. The air in the atmosphere, which is a mixture of several gases has certain mass and although not very dense, will acquire some weight due to gravitational force of attraction when the entire column of the atmosphere from the ground level to the top of it is considered. Pressure is defined as the force for unit area. Therefore, the atmospheric pressure is defined as the force exerted by an air column of units area of cross section extending from earth’s surface to the top of atmosphere. As we go up in the atmosphere the height of the air column decreases, the air also become rarer and the atmospheric pressure decreases with increase in height.

In meteorology, temperature is always referred to as the temperature of the air unless it is stated otherwise. There will always be exchange of heat in the atmosphere from a point at high temperature to a point at lower temperature. The transfer of heat through convection and radiation is always observed in the atmosphere whereas the conduction of heat takes place near the earth’s surface.

4.1 Diffusion of Heat

Heat diffuses (spreads) at different rates through different media, the rate at which diffusion of heat takes place is called thermal diffusivity. The thermal diffusinty of of some selected materials is given below:

One can see from the above table that iron has got higher diffusivity compared to wood. Suppose one end of iron rod is kept at hot temperature, the heat spreads faster in iron rod and the other end gets warmer quicker than in the case of a wooden stick which means that the transfer of heat is quicker in bodies with higher thermal diffusivity.

Three fundamental processes that are responsible for inducing changes in weather are transfer of heat, energy and mass. The Sun, whose inter-surface temperature is estimated to be around 6000°C emits heat energy in the form of solar radiation which is received at the earth’s surface after it is partly depleted in the atmosphere. Therefore, it is essential to understand the processes that govern the transfer of heat in the earth-atmosphere system.

3.1 Conduction

The transfer of heat from one point to another point within the material medium without the actual movement of the particles in the medium is called conduction i.e. the heat energy transfer is conducted by the particles in the medium from hot end to cold end. If a metal rod is heated at one end, the other end of rod becomes hot gradually due to transfer of heat by conduction. In the earth atmosphere system, conduction of heat is observed at the ground surface only. The amount of heat energy transferred due to conduction (Q) is

Air is one of the primary things that make life on earth possible. The earth’s atmosphere or air is made up of variety of gases and other particles. The dynamic layer surrounding the earth’s surface containing various mixture of gases, moisture and solid particles (aerosols) is called atmosphere. The atmosphere is generally defined as the gaseous envelop surrounding the earth.

The formation of the earth was believed to be about five billion years ago. In the first 500 million years, a thick atmosphere emerged from the vapour and gases that were expelled from the interior of the earth. Hydrogen (H2 ), water vapour, methane and carbon dioxide were some of the gases believed to be initially formed in the atmosphere due to out gassing from the interior of the earth. About 3.5 billion years ago, the atmosphere consisted of carbon dioxide (CO2 ), Carbon monoxide (CO), water vapour (H2 O), nitrogen (N2 ) and hydrogen present in atmospheric layers like troposphere, stratosphere, mesosphere, thermosphere (Fig. 2.1). The condensation of water vapour into water led to the formation of oceans in which sedimentation occurred and the hydrosphere was created. In the initial and ancient environment, oxygen was not present. Anaerobic is technical word which literally means without air (where air is generally used to mean oxygen and aerobic indicates the presence of oxygen). Evidence of such an anaerobic reducing atmosphere was hidden in early rock formations such as iron and uranium in their reduced states.

Aristotle (384 to 322 BC), an ancient Greek philosopher and scientist (Fig. 1.1) developed the concept of meteorology as a study of the lower atmosphere. Over the years meteorology developed as a science of atmosphere which deals with the physics, dynamics and chemistry of the atmosphere and their effect upon the earth’s surface, oceans and thereby life in general either directly or indirectly.

As the atmospheric conditions change from time to time in a given area and from place to place in a given time, climatology was developed as a science which studies the average conditions of the weather and its variability over a long period of time.

All most all the human activities are greatly influenced by the weather and climate to a greater extent. Therefore, the scope of meteorology encompasses various activities which are of considerable economic significance as detailed here below;

1.1 Housing

The design and construction of houses, buildings, industrial structures etc. depends upon the weather and climate of the region. Orientation of doors, windows roofs of the buildings are usually designed to provide maximum comfort and convenience to the people.

Introduction

Before start of this chapter some pertinent questions need to be answered. What are different agro ecology and what are the problem soils. Since dawn of agriculture in early 2000 B.C. man has been doing agriculture as subsistence farming to cater the needs for his own consumption. Later on as the population increased, the availability of land per pearson reduced and further the commercialization of agriculture after world war II, particularly in industrialized nation, compelled farmers to increase productivity per unit area. The green revolution involving higher fertilizer uses, more use of agrochemicals together with evolvement of improved crop varieties in later part of twentieth century played vital role in producing higher grain production resulting the global production triplet in contrast to merely increase in total global cultivated area to the extent of 10%.

The catastrophe of green revolution was realized in later years when reports of soil health degradation started appearing. Intensified agriculture characterized by excessive use of fertilizers, agrochemicals and unsupportable level of over exploitation of natural resources led to serious degradation of ecosystem. Thus management of agroecosystem has reached to a crossroad with serious pressure to increase productivity simultaneously holding the soil health with prime concern for future generation. Thus the soil heath under different agroecosystem are posing problem as the soil productivity has not reached to plateau level but has started reducing year after year. Thus such soils are becoming problem which need special attention to bring them back to support higher crop production.

Introduction

Land capability classification is one of the very important issues in terms of sustainable land use. Land is the most valuable natural resource which needs to be harnessed according to its potential. Land use planning and management is a known strategy for achieving sustainable development. A properly prepared land use plan based on sound scientific and technical procedures, and land utilization strategies can summarize rationally the future demands. This accompanied by a strong planning process, where communities and various stakeholders are involved, can strengthen the decision making process on allocation and utilization of land resources. Land capability is referred as suitability of the land based on inherent characteristics of the soil associated land features, and climatic conditions that limit their safe use under agriculture, forestry etc. Land capability classification is a system of grouping soils primarily on the basis of their capability to produce common cultivated crops and pasture plants without deteriorating over a long period of time. The capability classification is one of a number of interpretive groupings of soils made primarily for agricultural purposes, mainly based on the inherent soil characteristics, external land features and climatic factors that limit the use of land for agricultural purposes. The land capability is governed by the different land attributes such as the type of soil, its depth and texture, underlying geology, topography, hydrology, etc. It also includes soil irrigation classes and ground water table position to decide overall suitability of lands for sustained use under irrigation. The classification points out automatically the possibilities and limitations of the climate and soil for each crop and type of agriculture.

Introduction

Soil pollution is anything that causes contamination of soil and degrades the soil quality. It occurs when the pollutants causing the pollution decrease the quality of the soil and convert the soil inhabitable for micro and macro organisms living in the soil. Soil pollution can occur either because of human activities and/or natural processes. However, mainly it is due to human activities. The soil contamination can occur due to the presence of chemicals such as ammonia, pesticides, lead, herbicides, mercury, nitrate, naphthalene, petroleum hydrocarbons, etc. in an excess amount.

Soils can be polluted with several organic and inorganic pollutants. Organic pollutants contain hazardous persistent organic compounds viz. polychlorinated dibenzofurans (PCDFs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzodioxins (PCDDs), polychlorinated biphenyls (PCBs), polychlorinated naphthalines (PCNs) and other persistent organic compounds. Inorganic pollutants contain heavy metals like lead (Pb), cadmium (Cd), mercury (Hg), zinc (Zn), copper (Cu), arsenic (As) and nickel (Ni) as well as some radioactive compounds or radionuclides. The major sources of soil pollutants are anthropogenic. It contains mainly two sources, point and diffuse; the point sources contains industrial wastes, municipal wastes, domestic wastes, medical wastes, agrochemicals, agricultural wastes, composts and sludges and nuclear wastes. Organic and inorganic soil pollutants can be toxic for plants, animals soil organisms and others. Some compound of the soil pollutants enter into the food chain and can adversely affect on human health. Soil pollutants can be also transferred to surrounding air and water through leaching, volatilization, runoff and dust storms. Quality of air and water adversely affected can be degraded. Thus, remediation of polluted soils has become an awful necessity in many areas of the world.

Introduction

The term multipurpose trees (MPT) refers to all woody perennials that are grown to provide more than one significant function (shelter shade, land sustainability) of the land use system they implement. More emphasis is given to trees which are indigenous in nature and have the capability to fix atmospheric nitrogen. All trees are said to be multipurpose. The term “multipurpose” as applied to trees for agroforestry refers to their use for more than one service or production function in an agroforestry system (Burley and Wood, 1991).

Multipurpose trees species (MPT) are grown to provide more than one significant crop of function or form. These may include fuel wood, fiber, fodder, flower, fruit, fertilizer (6F) timber, industrial purpose, nitrogen f ixing, soil conservation, soil protection and rehabilitation, shade and nurse trees, medicine, windbreak, shelterbelts, live fences, aesthetic or recreational purpose, shown in Table 16.1.

Remote sensing

It is the art and science of obtaining information about an object, area, or phenomenon through the analysis of data acquired by a device without being in physical contact. Remote sensing technology involves acquiring information about the earth’s surface and atmosphere, using satellite based sensor, interpretation, of spectral measurements and characterization of land resources and environmental phenomena.

The information recorded by this technology is not visible to humankind. It provides synoptic view as well as three-dimensional view of larger area. And data are received periodically and helps in monitoring the changes at short intervals. The data recording is unbiased one which is stored permanently and can be used in many applications. Thus, processing of data is faster than the conventional interpretation method. Thus, soil resources data collected by extensive ground surveys and soil maps were prepared using cartographic techniques these were tedious, costly and time consuming. Multi date, multi spectral and real time satellite data provide a reliable accurate tool for assessment and repeat coverage of the same area at the same local time for monitoring soil resources (Joshi, 2013). In remote sensing, reflected energy from the object is recorded by a sensor. The information about the object is obtained through the analysis of reflected rays. Three energy interactions occurs when electromagnetic energy falls on any surface feature i.e., reflection, absorption and transmission.

Introduction

One of the most common concerns in irrigated agriculture is regarding water quality or salinity. Out of the ground water surveyed in different Indian States, as much as 84% is rated either saline or alkaline (Minhas 1996). Salinity management is very important for using saline water in irrigation safely. This requires an understanding of how salts affect soil as well as plants, of how hydrogeologic processes affect salt accumulation, and also of how cropping and irrigation activities affect soil and water salinity.

The objectives of management practices for getting optimal crop production with saline irrigation water include the prevention of salt build-up in soil which limit the productivity of soils and the control of salt balances in the soil-water system, as well as minimising the damaging effects of salinity on crop growth (Meiri and Plaut 1985). Amongst the various soil, water, and crop management options available, there is usually no single way to achieve safe use of saline water in irrigation but many different approaches and practices can be combined into satisfactory irrigation systems using saline water. The appropriate combination depends upon edaphic, hydrogeologic, climatic factors as well as social and economic condition of the farmer. Several practices interact with each other, and should be considered in an integrated manner, along with climatic and human factors. Because of the climate, the basic principles of saline water management need some adaptation, e.g. providing for a leaching requirement is not appropriate when the growing season for post-monsoon winter crops starts with a surface-leached soil profile, because it would increase the salt load. High salinities during the initial stages of growth are particularly harmful. Recommendations for effective management of irrigation water salinity depend upon local soil properties, climate, and water quality; options of crops and rotations; and irrigation and farm management capabilities

Introduction

Irrigated agriculture is dependent on an adequate water supply of usable quality. The water quality used for irrigation is essential for the yield of crops, maintenance of soil productivity, and protection of the environment as well. The quality of irrigation water is defined with respect to its effect on plant growth, soil properties, soil biological equilibrium, and irrigation technology. Conceptually, water quality refers to the characteristics of a water supply that will influence its suitability for a specific use, i.e. how well the quality meets the needs of the user. Specific uses have different quality needs and one water supply is considered more acceptable (of better quality) if it produces better results or causes fewer problems than an alternative water supply. For example, good quality river water which can be used successfully for irrigation may be unacceptable for municipal use without treatment to remove its sediment load. Similarly, snowmelt water of excellent quality for municipal use may be too corrosive for industrial use without treatment to reduce its corrosion potential.

Introduction

Black cotton soils are formed by the solidification of molten magma; it covers a large area of the Deccan plateau. The depth of this soil is very high in the lower part of the Krishna – Godavari basin. The clay fraction is very high which is responsible for the heavy waterlogging in the area of heavy rainfall and become more vulnerable to soil erosion. The fine fraction of soil not allows draining out through the soil profile and at the same time the rate of evaporation is low. During summer soils suffer from moisture stress and it becomes very hard but at the same time during the rainy season moisture content very high. this imposes severe constraints on conventional agriculture use as a result most of the land remains fallow and subjected to soil erosion due to heavy rain. The nutrient status of the soil is quite good in Vertisol but these constraints limit crop production. To manage black cotton soil for crop production it is advisable to use animal-powered devices for surface soil drainage, Counter cultivation, adoption of a new cropping system will be helpful for better crop production.

Introduction

Desert soils are the soils of arid regions that remain dry for most part of the year and support sparse xerophytes. The amount of water received by precipitation is far less than what is lost by evapotranspiration. Most deserts receive an average precipitation of less than 400 mm. Because of extreme imbalance between evapotranspiration and precipitation, many desert soils contain salts.

Distribution

Deserts occupy about one-third of the areas of Africa and Australia, 11% of Asia and about 8% of the Americas (Boul et al. 1997). Desert soils include both cold and hot desert. In India, desert soils occur in three agro-ecological regions (AER). The cold arid desert of extreme north (Leh, Ladakh region of Jammu & Kashmir ), the hot arid desert of north western India (Rajasthan, southern parts of Haryana and Punjab and northern parts of Gujarat) and the tropical arid desert of the Deccan plateau in South India represents AER 1, 2 and 3, respectively. The three different desert regions in India have characteristic climatic and soil conditions.

Introduction

Calcareous soils are those that contain high levels of calcium carbonate (CaCO3 ) that affects soil properties related to plant growth, such as soil water relations and the availability of plant nutrients (Elgabaly, 1973), and give effervescence visibly releasing CO2 gas when treated with dilute 0.1 N hydrochloric acid. The pH of calcareous soil is > 7.0 and also regarded as an alkaline (basic) soil.

Calcareous soils have often more than 15% CaCO3 in the soil that may occur in various forms (powdery, nodules, crusts etc.). Soils with high CaCO3 belong to the Calcisols and related calcic subgroups of other soils. They are relatively widespread in the drier areas of the earth. They occupy >30% of the earth’s surface, and their CaCO3 content varies from just detectable up to 95% (Marschner, 1995).

Formation of calcareous soils

Calcareous soils occur naturally in arid and semi-arid regions because of relatively little leaching. They also occur in humid and semi-humid zones if their parent material is rich in CaCO3 , such as limestone, shells or calcareous glacial tills, and the parent material is relatively young and has undergone little weathering. Some soils that develop from calcareous parent material can be calcareous throughout their profile. This will generally occur in the arid regions where precipitation is scarce. It has been estimated that these soils comprise over one-third of the world’s land surface area (Taalab et al. 2019, Aboukila et al. 2018).

Introduction

Environment pollution is a burning topic of the day. Air, water and soil are being polluted alike. Soil being a “universal sink” bears the greatest burden of environmental pollution. It is getting polluted in a number of ways. There is importance in controlling the soil pollution in order to preserve the soil fertility and increase the productivity. Pollution may be defined as an undesirable change in the physical, chemical and biological characteristics of air, water and soil which affect human life, lives of other useful living plants and animals, industrial progress, living conditions and cultural resources. A pollutant is something which harmfully interferes with health, comfort and environment of the people. Most pollutants are introduced in the environment by waste, accidental discharge, sewage or else. They are by-products or residues from the production of something useful. Due to this our valuable natural resources like air, water and soil are getting polluted. The basis of agriculture is Soil. All crops for human food and animal feed depend upon it. We are losing this important natural resource by the accelerated erosion to some extent. In addition to this the huge quantities of man-made waste products, sludge and other product from new waste treatment plants, and even polluted water are also causing or leading to soil pollution. In order to preserve the fertility and the productivity of the soil.

Submerged soils/Flooded soil

Submerged soils are the type of soils that are saturated with water for a sufficiently long time in a year. This gives the soil the following distinctive gley horizons resulting from oxidation-reduction processes:

The soil is intermittently saturated with water, oxidation of organic matter is slow and it accumulated within the “A” horizon. Fe and Mn are deposited as rusty mottles or streaks if the diffusion of O2 into the soil is slow in the second horizon, whereas if the diffusion is rapid, they are deposited as concretions.

Types of submerged soils

1. Waterlogged soils- Waterlogged soils are saturated with water for a sufficiently long time annually to give the soil the distinctive gley horizons resulting from oxidation-reduction processes. Saturation with water may be due to impermeability of the soil material, or the presence of an impervious layer, or a high water table.

2. Marsh Soils- These types of soils are more or less permanently saturated or submerged. Freshwater marshes can be classified according to their origin into upland, lowland, and transitional. Upland marshes are poor in bases and have pH 3.5-4.5 because they receive mainly rainwater. Lowland marshes are saturated or submerged with water-carrying bases and have pH 5.0-6.0.

Introduction

Soil is one of the crucial natural resources that support life on the earth and controls the economic conditions of the nation. Soil erosion has become a serious problem in both rainfed and irrigated areas of India thus it of vital importance to raise awareness about soil erosion and their reclamation / management methods, so that future land management decisions can lead to more sustainable and resilient agricultural systems. In India almost 130 million hectares of land, i.e., 45 % of total geographical surface area, is affected by serious soil erosion through gorge and gully, shifting cultivation, cultivated wastelands, sandy areas, deserts, and water logging.

In India, the soil is eroded at an average annual rate of 16.35 tonnes per hectare which means 5334 million tonnes per year for the country as a whole. Out of this, about 29 per cent is permanently lost to the sea, while 61% is simply transferred from one place to another, and the remaining 10% is deposited in reservoirs (which mean the storage capacity is reduced by 1-2 per cent annually (Narayana and Ram Babu, 1983)). Singh et al. (1990) estimated that the average annual soil loss is about 15.2 tonnes per hectare and at national level it amounts to about 4978 million tonnes annually. The annual erosion rates vary from region to region. In dense forests covers, snow-clad cold deserts and arid regions of western Rajasthan, the annual erosion rates are less than 5 tonnes per hectare. On the other hand, about 64 per cent of the total soil is contributed by highly to very severely eroded areas, such as the Shiwalik hills (annual rate is more than 80 tonnes per hectare), the Western Ghats, black and red soil regions, ravines and other gully eroded areas and the northeastern region. For the first time, Gurmel Singh prepared map of soil erosion in India (Fig. 7.1), on the basis of iso-erosion lines i.e. line joining the place of same erosion rates.

Introduction

The optimum soil pH for plant production is one that is slightly acidic, at this pH soil microorganisms are most active and plant nutrients are readily available. At extremes of high (alkaline) and low (acidic) pH this delicate balance is disturbed and plant nutrients that were in adequate supply can become either deficient or toxic to plant growth. Some essential nutrients such as phosphorous, calcium, magnesium and molybdenum become unavailable if the soil pH becomes too acidic. Acidic conditions will result in a lowering of plant production in farming systems. This will result in reduced profitability and an increased reliance on fertilizers to sustain any form of productive agriculture. Correcting soil pH to a more favorable pH range will increase the availability of essential nutrients.

Introduction

Soils are formed by weathering of rocks and minerals and all soils contain some amount of soluble salts. Many of these act as a source of essential nutrients for the healthy growth of plants. However, when quantity and quality of salts in the soil near rhizosphere exceeds a particular value, growth, yield and/or quality of most crops is adversely affected. Such a soil is called salt-affected. The degree of adverse effects depends upon the type and quantity of salts, crop and its variety, stage of growth, cultural practices and environmental factors viz. temperature, relative humidity, and rainfall etc. Development of salinity and waterlogging is a serious problem in arid and semi-arid regions of the world and threatening the sustainability of irrigated agriculture.

Soil degradation resulting from salinity and sodicity is a major environmental threat to soil fertility and agricultural productivity in arid and semiarid regions of the world. Saline–sodic soils are degraded due to the simultaneous effect of salinity and sodicity. This causes loss of soil physical structure by clay swelling, and dispersion because of high Na+ concentrations in the soil solution or at the exchange phase. Apart from these physicochemical effects, this leads to biological properties, such as microbial respiration and biomass, becoming worse. On the other hand, salinity affects plant growth by creating osmotic imbalances and specific ion toxicities, which pose limitations to morphological, histological, chemical, biochemical, and metabolic processes. In turn, these reduce stomatal opening and photosynthetic rate, leading to decreased plant growth, crop yield, and quality.

Introduction

Pedology:- Pedology word drive from Greek word pedon, means soil or earth and logos means to study. Pedology is concerned with origin of the soil, its classification, distribution and character (Physical, Chemical and Biological).

Definition:- Soils are natural bodies made from both mineral and organic materials and capable of supporting plants out-of-doors.

Composition of soil on volume basis (Soil components)

i. Mineral matter :- 45%

ii. Organic matter :- 5%

iii. Soil water :- 25%

iv. Soil air :- 25%

Soil formation is a long term process. It takes several million years to form a thin layer of soil. The soil is made up of broken down rock material of varying degree of fineness and changed in varying degrees from the parent rocks by the action of different agencies such that the growth of vegetation is made possible. As soil is a complex mixture of various components, its formation is also more complex. The Formation of a particular type of soil depends upon the physico-chemical properties of the parent rock, intensity and duration of weathering, climatic and other parameters.