eChapters

Introduction

Diazotrophs are phylogenetically diverse microbes spanning over various classes varying vastly on basis of physiological properties (Young, 1992), include various phototrophic microorganisms aerobic phototrophic Cyanobacteria (Vaishampayan et al, 2001), anaerobic purple-sulfur phototrophs like Chromatium, and green-sulfur phototrophs, e.g. Chlorobium, Rhodopseudomonas; chemolithotrophs Alcaligenes, Thiobacillus, Methanosarcina, Methanobacterium, Desulfovibrio or Azospirillum lipoferum and heterotrophic bacterial anaerobes (Clostridium), microaerophiles (Herbaspirillum), and aerobes (Azotobacter). Free-living aerobic nitrogen fixing bacterial genera found in soil include obligate aerobes as Azotobacter, Beijerinckia, Derxia, Achromobacter, Mycobacterium, Arthrobacter and Bacillus but the majority are microaerophilic (e.g. Azospirillum, Herbaspirillum) or facultative and obligate anaerobes (e.g. Klebsiella, Aerobacter, Desulfovibrios, Rhodospirillum, Clostridium, Erwinia).

Introduction

Nitrogen-fixing cyanobacteria are the group of most primitive prokaryotes that have been observed in proterozoic era. Many Proterozoic oil deposits are attributed to the activity of Cyanobacteria, such as Gloeocapsomorpha. Small concentrically layered structures called pisolites are also the result of fossilized bacteria.

Introduction

Rhizobia and Frankia are soil bacteria that exhibit symbiosis with their particular hosts owing to their ability to understand the intricate signals excreted by the host roots. Rhizobia exhibit symbiosis with legumes and one species member of Ulmaceae family Parasponia andersonii while actinomycetes Frankia forms the group of nitrogen-fixing bacteria that live in symbiosis with a large spectrum of dicot plants distributed among eight families consisting of over 24 genera and around 200 species of angiosperms (Benson and Silvester, 1993) and are collectively responsible for 15% of the biologically fixed nitrogen in the world. This Frankia-woody tree or dicotyledonous plant interaction results in evolution of the actinorhizal plants and the symbiotic interaction is described between Frankia (actino) and plant roots (rhiza).

Introduction and History

Leguminosae/Fabaceae is a superfamily of dicotyledonous plants, which in species diversity is the third largest family of plants accounting for 5% of Earth’s plant biodiversity and make up for more than at least 1% of the total Earth plant biomass. Among these, legume grains and pulses having more than 20 to 30% lysine protein content are cultivated in 145 million ha of land in developing countries. This family is also characterized by presence of specialized tumor like structure formation (nodules) on roots (occasionally on stem as in Sesbania rostrata, Aeschynomene) that is inhabited by microsymbiont gram-negative bacteria (Rhizobium), engaged in fixing atmospheric nitrogen or symbiotic biological nitrogen fixation.

Mizoram in North East India, is located between 21º58’ to 23º35’ N latitude and 92º15’ to 93º29’ E longitude, surrounded by Tripura, Assam and Manipur in North frontier regions; Bangladesh in west; and Mayanmar in east and south. The undulated topography of Mizoram, known as Lushai hills during British period, has varied altitudes ranging from 21 to 2157 m above mean sea level, annual rainfall of 2000-3200 mm, and mean monthly temperature of summer (monsoon) ranges from 14.6ºC to 29.6ºC. Besides having good rainfall; the vegetable production, including leaf vegetables, during winter period is limited by acute soil moisture stress caused by high rate of evapo-transpiration, almost no rain from November-March, non-availability of irrigation water and low water holding capacity of the sloppy land (Singh et al., 2011; Singh et al., 2013b).

The edible speciality mushrooms are mushrooms that are generally not grown and available commonly in the market. Any mushroom other than popularly grown white button mushroom (Agaricus bisporus) falls under the specialty category, and these mushrooms are generally not available over the counter or in departmental stores in India or other countries in the world. The mushrooms under this group include the different types of commonly grown Oyster mushrooms like grey, black, white, pink, yellow oyster mushrooms, King Oyster mushroom, Shiitake mushroom, Black Ear mushroom, Shimeji mushroom, Enokutake mushroom, Milky mushroom, the Portabella brown, Cremini mushroom , Straw mushrooms and others. This paper will describe in detail biology and cultivation of these mushrooms as grown under controlled environment conditions or under seasonal growing conditions, where ever possible.

Gingers  belong to Zingiberaceae family and are made up of about 1000 species in 47 genera. They have numerous members with aromatic oils that have made them popular for perfumes and ornamentals. Ornamental gingers, while related to edibles, are usually grown for their looks instead of their flavor. A very large and diverse group of gingers are valued both for their tropical foliage and for their large, colorful flower heads. From the startling red ginger to the subtle shell ginger, these attractive plants are easy to grow in home landscapes in tropical and semi-tropical areas. They are great for tub gardens They can be very rewarding to grow, and with some simple care will continue to produce beautiful leaves and flowers for many years which also have cut flower value.

Kale (Brassica oleracea L. convar. acephala (DC.) Alef.) is a representative of cole group of vegetables and cool-season cooking green somewhat similar to collard and non heading cabbage that has gained recent widespread attention due to its health-promoting, sulfur-containing phytonutrients. Kale is grown for its large foliage which is mainly used as leafy vegetable. This leafy vegetable is helpful in reducing the chances of cancer if taken regularly. Among the vegetable crops, kale is the richest source of carotenoids which is the precursor of vitamin-A. Besides, it also contains good amount of different minerals essential for human diet. There are several varieties of kale, all of which differ in taste, texture and appearance.

Dyes are one of the most important by products of the plants, as they are related with cultural practices, rituals, arts and crafts, fabrics and to satisfy personal embodiment. However, dye yielding plants have not received significant attention (Grover and Patni, 2011). Dye is a substance that has affinity to the substrate to which it is being applied such as textile fibers, foodstuffs and powder. They are organic coloured substances which absorb light in the visible part of the spectrum and have the property of colouring the substrate they are applied to.
 
Colourants which are obtained from plants and natural sources are known as natural dyes. Natural dyes have been traditionally used in most of the countries. These dyes were obtained from roots, leaves and bark (Akhtar et al., 2012). Natural dyes find use in the colouring of textiles, drugs, cosmetics, etc. Owing to their non-toxic effects, they are also used for colouring various food products. In India, there are more than 450 plants that can yield dyes (Siva, 2007).

Black caraway (Bunium persicum Boiss. Fedtsch ) commonly known as kala zeera is a low volume,  high value, under-exploited and  non-perishable crop that finds place  in cold arid  North -Western Himalayan regions of Indian sub-continent. Its fruits are expensive spice and are used in indigenous system of medicine for curing various ailments and disorders. The proper information on botanical identity of the species, its description and distribution, active ingredients, standardized agro-techniques, processing and value addition and marketing potentials, etc. are very scanty. An attempt has been made to gather information on various aspects of kala zeera to promote its cultivation in the cold arid regions of the Himalayan states and its role in improving the socio-economic conditions of the people by cultivating the cash crop.

Broad dhaniya (Eryngium foetidum L.: Umbelliferae - Apiaceae) is an underutilized leafy vegetable and aromatic plant used for seasoning food items and source of medicine. It is a shade loving plant of tropical regions.  It has got status of a promising cash crop with huge export potential particularly in United Kingdom, USA and Middle East markets. Its medicinal and seasoning properties are well known in various countries like Vietnam, India and in the Amazon region (De Gumao et al., 2002). Broad dhaniya is relatively unknown in many other parts of the world and is often mistaken and misnamed for its close relative Coriander (Coriandrum sativum L.).

Dragon fruit, commonly known as pitaya/pitahya (Hylocereus sp.) is a  climbing perennial cacti belonging to the Cactaceae family and the subfamily Cactoidea of the tribe Cactea (Raveh et al., 1993). It is a perennial climbing cactus plant native to tropical areas of North, Central and South America. Main countries growing dragon fruit are Vietnam, Colombia, Mexico, Costa Rica, Nicaragua, Thailand and Taiwan. Cultivation also occurs in Australia, Israel and Reunion Island. The European Union and Asia, especially China are the largest import markets of dragon fruits (Vinas et al., 2012).

Tropical root and tuber crops are the third important group of food crops after cereals and pulses. Tuber crops hold a premier position among food crops in the tropical and subtropical regions of the world. These crops are rich in starch and calories and have great potential in meeting the food and energy needs.  More than 840 million people do not have enough food to meet their basic daily energy needs. Far more - an estimated 3 billion - suffer the insidious effects of micronutrient deficiencies leading to hidden hunger. Apart from its popular use as food, tubers also find an important space in cattle feed and agro industries sector.Tropical tuber crops possess high photosynthetic ability coupled with the capacity to yield under marginal lands, adverse biotic and abiotic stress etc (Ravindran et al., 2008).

The Indian Himalayan region is a well known abode to numerous plants of medicinal significance. The Western Himalayan ranges are home to a diverse flora of variety of endemic medicinal plants making it a biodiversity-rich region (Samant et al., 1998).  The ancient system of traditional medicines has been using these endemic medicinal plants since time immemorial. Of late the resurgence of herbal system of medication has led to an unprecedented rise in extraction of such plants from the wild for medical preparations. Most of the times the plant collection is unscientific and unthoughtful of ecological status of the medicinal plant, especially herbs. As a result, unplanned collection and other human interferences have brought a threat to survival of several important medicinal plants of the IHR an  example being  Brahmakamal.

The palmyrah palm exists both in the wild as well as in cultivation, ranging from sea level about 800 amsl. It is usually grown in seasonal tropical or subtropical climates on sandy soils. It is a very adaptable palm, however, growing well in dry areas and is quite drought resistant. It also grows in per-humid areas and survives water logging quite well. The worldwide distribution of natural and cultivated populations of the palmyrah shows that it occupies a band on either side of the equator and extends laterally over a considerable girth. The country wise distribution of the palms are Mauritania, Senegal, Mali, Gambia, Guinea-Bissau, Guinea, Ivory Coast, Upper Volta, Nigeria, Gaban, Congo, Sudan, Tanzania, Madagascar, Saudi Arabia, Iraq, Iran, Pakistan, Bangladesh, Sri Lanka, Myanmar (Lubeigt, 1977), Thailand, Cambodia, Malaysia and Indonesia (Kovoor, 1983). In India, the palms are wide spread in Kerala, Tamil Nadu, Karnataka, Andhra Pradesh, Maharashtra, Odisha, Madhya Pradesh, Bihar and West Bengal.  Isolated patches are also seen in Assam, Gujarat and Uttar Pradesh (Anonymous, 1948). The palmyrah is considered as a slow grower and the growth rate decreases in regions of higher altitude (Tjitrosoepomo and Pudjoarinto, 1982).

Wild edible plants have played an important role in human life since time immemorial. People depend on the wild plant resources for various purposes like fire wood, timber, non-timber forest products, medicines and food (Pushpangadan, 1995). In many cases, rural communities depend on wild edible plants, to meet their food needs in periods of food shortage. Indian subcontinent is blessed with varied and diverse soil and climate conditions suitable for the growth of various plant species. It has been estimated that 9000 of the 15,000 higher plants occurring in India are commercially useful. Of these 7500 are medicinal, 3900 are edible, 700 are culturally important, 525 are used for fiber, 400 are fodder, 300 for pesticides and insecticides, 300 for gum, resin and dye and 100 for incense and perfume (Anonymous, 1992-1993).

Ever since the dawn of civilization, dependence on plants has been indispensable for human survival. Transformation from food gathering to settled agriculture necessitated domestication of plant species useful for mankind leading to co-evolution of plants and man in absolute harmony with nature. Natural disasters like famines, floods, epidemics have often led people to search new plant species for human consumption. Out of an estimated total of 80,000 plants of possible economic use, about 30,000 plants have been found to be edible in nature and approximately 7,000 plants have been cultivated by mankind at one time or the other, of which only 158 plants are widely used for food (Wilson, 1992). Among these, 30 crops provide 90% of the world’s food and only 10 crops supply 75% of the world’s food budget. Out of the above only three crops, rice, wheat and maize provide 60% of the world’s total food requirement (Paroda, 2000). This dangerously narrow level of food base may imperil the existence of mankind during a time of impending crisis in unforeseen times in the future.

Nowadays, revolutionary changes in entire globe have led to the economic, cultural and scientific development in our society and have augmented considerable changes in our food habits and life-style. Continuously growing population had noticeably increased the pressure on land, water and energy resources. All these resources are scarce and going to be exhausted in coming decades at the present rate of consumption. Undoubtedly, production of food is more imperative than the production of energy or any other bioproducts. Moreover, with the world population rising to 9 Billion in 2050, with many inspiring to a western life style and diet, this challenge should be addressed urgently (Draismaa et al., 2013). The challenge to produce about 70% more food by 2050 for a growing and increasingly affluent world population has motivated several review papers addressing the different dimensions of the food system and food security (Verburg et al., 2013). Presently, human beings consume approximately 2.5 billion tons of dry weight of harvested crops which include approximately 2.3 billion tons of cereals (e.g., rice, wheat, and corn kernels) and grass from managed pastures (Smil, 2000).

Halophytes are salt-resistant or salt-tolerant plants which thrive and complete their life cycles in terrestrial or aquatic habitats having high salt concentrations. Aronson (1989) compiled a partial list of halophytes containing 1560 species in 550 genera and 117 families. Menzel and Lieth (1999) listed as many as 2600 plants under salt tolerant flora. Although halophytes represent only 2% of terrestrial plant species, they are present in about half the higher plant families and represent a wide diversity of plant forms. Because of their diversity, halophytes are regarded as a rich source of potential new crops. Halophytes are tested as vegetables, fodder and oilseed crops under field trials. The oilseed halophyte, Salicornia bigelovii, yields 2 tones/ha of seed containing 28% oil and 31% protein, similar to soybean yield and seed quality.

1. Introduction
 
The bryophytes are found everywhere in the world except in the sea. They grow on wet soil or rock, the trunk of trees, in lake, river and even in Antarctic island. The bryophytes are placed taxonomically between algae (Fig. 1) and pteridophytes (Fig. 2); there are about 24,000 species in the world. They are further divided into three phyla, Bryophyta (mosses 14,000 species, Fig. 3), Marchantiophyta (liverworts 6,000 species, Fig.4a,b) and Anthocerotophyta (hornworts 300 species, Fig. 5). They are considered to be the oldest terrestrial plants, although no strong scientific evidence for this has appeared in the literature. This hypothesis was mainly based on the resemblance of the present-day liverworts to the first land plant fossils, the spores of which date back to almost 500 million years. Among the bryophytes almost all liverworts possess beautiful cellular oil bodies (Fig. 6) which are peculiar, membrane-bound cell organelles which consist of ethereal terpenoids and aromatic oils suspended in carbohydrates- or protein-rich matrix, while the other two phyla do not. These oil bodies are very important biological markers for the taxonomy in the Marchantiophyta (Asakawa, 1982, 1995; Asakawa et al., 1979b, 2008c, 2012b, 2013a,b; Asakawa and Ludwiczuk, 2008a,b; Ludwiczuk and Asakawa, 2010).

Climate change and variability are concerns of humankind. The recurrent drought and desertification threaten seriously the livelihood of over 1.2 billion people who depend on land for most of their needs. The global economy has adversely been influenced due to droughts and floods, cold and heat waves, forest fires, landslips and mudslips, icestorms, duststorms, hailstorms, thunder clouds associated with lightning and the sea level rise (Fig. 1). The year 1998 was the warmest and declared as the weather related disaster year, which caused hurricane havoc in Central America and floods in China, India and Bangladesh. Canada and New England in the U.S suffered heavily due to icestorm in January while Turkey, Argentina and Paraguay with floods in June 1998. In contrast, huge crop losses were noticed in Maharashtra (India) due to unseasonal and poor distribution of rainfall during 1997-98. The 1997/1998 El Nino event, the strongest of the last century affected 110 million people and costed the global economy nearly US$ 100 billion. A string of 16 consecutive months saw record high global mean temperature in 1997-98.

Mini seed testing lab analytical register

Seed storage is the preservation of viable seeds from the time of collection to the required for sowing. It is important to get adequate plant stands in addition to healthy and vigourous plants.

Objectives

i. To maintain initial seed quality during storage period by providing suitable conditions.

ii. To maintain the seed germination and emergence rates.

iii. To prevent the seed deterioration during storage period.

iv. To maintain the physical and physiological seed qualities.

The seed moisture content is the amount of water present in the seed. It is generally expressed in percentage of dry and wet seed weight. It is the loss in weight of the original sample when it is dried. High moisture content in seed sample favors the mechanical damage, seed longevity, incidence of disease and insect pests.

Objective

i. To know the moisture content of seeds by suitable methods
ii. To suggest the seed drying.

Seed Viability Test

Germination test for a seed lot is a pre-requisite to know its potential of emergence under field condition. However, this test requires few days to weeks and a month in some cases. Tetrazolium test gives quick information on seed viability or germinability. It makes possible to distinguish red coloured living parts of seeds from the colourless dead ones. Staining of seeds determines  viability.  Completely  stained  seeds  are  viable  while,  partially and comparatively unstained seeds are non-viable. This test is not valid as compared to seed germination test.

Seed Germination Test

Germination is the process of emergence and development of seed embryo into a plant under favourable environmental conditions of water, soil, sunlight and temperature. The best example of germination is the sprouting of a seedling from a seed of an angiosperm plant. It reflects the ability of seed to produce a normal plant under favourable environmental conditions. The germination rate of a particular seed lot is a key indicator of its performance in the field.

Physical purity test determines the proportion of pure seed, other crop seed, weed seed, inert matter, moisture and germination components in the seed lot by weight in percentage in accordance to prescribed Seed Standards. It thus, helps in improving the plant stand, raising a pure crop by eliminating other crop seeds, weed seeds and disease free-seeds. Seed must not be sold until the percentage of pure seed, other crop seed, weed seed, and inert matter are in accordance to seed physical purity standards. Physical purity test is required for seed certification or seed law enforcement and it is a pre-requisite for ger- mination test.

1. Isolation distance

Seed Sampling

The size and quantity of seed sample required for seed quality testing remains small as compared to the seed lot hence, representative samples are randomly drawn for this purpose. The process of obtaining a uniform and representative sample from a seed lot for seed quality testing is called seed sampling. The samples are prepared in accordance to ISTA rules to ensure that small size sample should represent truly and in the same proportion all constituents of seed lot.

Seed
The seed, in botany is a mature ovule, consisting of an embryo together with a store of food all surrounded by a protective coat and bear ability to develop a new plant on optimum conditions of soil, moisture and light. It usually develops after the fertilization on an egg cell by male generative cell from a pollen grain. Seeds of some species develop without the intervention of the male cell, formed entirely of ‘mother’ tissue. Such seeds are called apogamic seeds. In seed technology, the seed is seed or any vegetatively propagated material produced from seed crop in accordance to Indian seed standards and has potential to develop new crop in presence of soil, moisture and light.

Notified Varieties of Different Seed Spices

India is famous as the ‘Land of Spices’ world over. Spices are nature’s gift to humankind for flavoring our food. They are also used as preservative and in pharmaceuticals. India is the largest producer, consumer and exporter of seed spices and their value added products. About 63 different spice crops are cultivated in the country. Among them, seed spices are annual herbs, whose dried seeds or fruits are used as spices. These crops share 21.87% in terms of quantity and 7.42 % in terms of value to total spices export in the country. The country grows a wide variety of seed spices like coriander, cumin, fenugreek and fennel as major crop, while, dill, nigella, ajwain, anise, celery, caraway, parsley, black cumin and few other are categories as the minor seed spices.

Abstract

The paper presents an approach of selecting suitable areas for artificial groundwater recharge structures through remote sensing and integrated terrain analysis by statistical method. The study area “Ayyar basin” is an aquifer system of gneisses and charnockite litho-units in Tiruchirappalli district, Tamil Nadu. The area has witnessed a steady decline in groundwater table. Hence, the scope for artificial groundwater recharge was studied in this area with the help of Tamil Nadu State Council for Science and Technology (TNSCS&T).

Abstract

Water has become a scarce resource all over the World. Water resources of Earth can be classified as surface water and groundwater in which groundwater is the main source for the drinking, domestic and agriculture. The Pudukkottai district is one of the chronic drought prone areas in Tamil Nadu. But, at the same time, the district is pitted with over 5,400 tanks/water bodies widely distributed throughout in general and clustered more in Vellar delta in particular, as the interlobel depressions have provided basic depressions for the surface water to accumulate. However, these surface water bodies are heavily silted. In Pudukkottai district, there are three divergent aquifer systems, hard rock aquifer system in the western, sedimentary aquifer system constituted by the Tertiary Sandstone (Cuddalore Sandstone) in the central and Quaternary aquifer system constituted by fluvial, fluvio-marine and marine systems in the eastern parts of the district.

Abstract

The development index and the developmental planning of a Country/Nation mostly depend on its natural resources potential including water resources. The fast emerging Remote Sensing and GIS technology has substantially reduced the problems of water resources management including groundwater. The groundwater is distinctly controlled by western crystallines, central Tertiary sandstone and eastern Quaternary sediments in Pudukkottai district. While the groundwater behavior in crystallines is dominantly controlled by secondary porosity, in Tertiary formations and Quaternary sediments, it is controlled primarily by the primary porosity and by secondary porosities also if these are structurally deformed.

Abstract

It is evident from the previous studies that, in the crystalline terrain, the Fractures / lineaments act as master conduits for the groundwater movements and also act as favorable loci for groundwater storage. Because of this, the mapping of fracture patterns has become very popular among geoscientists. However, after witnessing failures and the fractures turned out to be water barren at many instances, geoscientists have started concentrating more on understanding the origin and the morphology of the fractures for precise groundwater targeting. In this context, a study has been conducted in parts of Western Ghats in Madurai, Dindigul and Theni districts of Tamil Nadu, South India, using remote sensing and geographic information system (GIS). In the said study, the maxima zones of transmissivity were studied in relation to fractures systems, which are normally reflected as lineaments in satellite images in the area. This study in general indicates that the transmissivity is controlled by the fractures, which are interestingly the active faults of the Quaternary period in the area.

Abstract

The groundwater targeting in hard rock aquifer systems is complex, because of the heterogeneity of the aquifer systems. The ground water mobility and stability in such aquifer systems varies because of the lithology, folded structures, fracture density, geomorphology, slope etc., These occur in various permutations and combinations and control the overall water holding and conducting capacity in different parts of the aquifer systems. Hence, one needs to analyse all the data so as to understand and bring out precise spatial models on the groundwater probability in hard rock aquifer systems. In the present study, the authors have carried out GIS based appraisals to understand the relation between the lithology and groundwater movement in hard rock aquifer systems of parts of Central Tamil Nadu covering 1300 sq.km. In the said study, GIS images were generated on the maxima zones of various aquifer parameters such as water level, width of aquifer depletion, transmissivity, permeability, specific capacity, storage co-efficient, optimum yield and recovery rate. These were overlaid with the lithology GIS image. Such an analysis has shown that, in general, the fissile hornblende biotite gneiss appears to have some control over the groundwater systems.

Abstract

The groundwater behaviour in hard rock aquifer systems has always remained enigmatic owing to the heterogeneity of the aquifer systems. This is the reason why there are a lot of failures in groundwater targeting and management in hard rock aquifer systems even after the employment of many modern technologies. For precise groundwater targeting in hard rock aquifer systems various parameters like lithology, the type and the degree of structural deformation, the degree of weathering, geomorphology, etc., will have to be analysed which involves spatial analysis of voluminous data. In the sphere of spatial modelling, GIS plays an important role. Hence, a newer study has been carried out in parts of Madurai, Dindigul and Theni districts, Tamil Nadu, to identify the groundwater provinces and their functions using GIS. In the said study, GIS images were generated on the groundwater targets through GIS integration of transmissivity, permeability, storage co-efficient and water level. Such GIS image showing groundwater maxima was overlaid with GIS image of fracture maxima, subsurface geology maxima and the geomorphology maxima and thus by various GIS based spatial manipulations, aquifers controlled by structure, geomorphology, subsurface geology, and combinations of the above various variables were brought out. This has provided potential method for precise targeting of groundwater.

Abstract

Remote Sensing (RS) and Geographic Information System (GIS) have emerged as potential tools for competent planning and administration of water resources. In this study, a new methodology is proposed to delineate groundwater target zones using integrated RS, GIS and Analytical Hierarchy Process (AHP) method. The developed methodology is confirmed by a case study in Karur district of Tamil Nadu, Southern India. Seven thematic layers, viz., Lithology, Lineament Density, Geomorphology, Slope, Post– Monsoon Water Level, Drainage Density and Land use / Land cover were considered in this study. Selected seven thematic layers and their features were assigned suitable weights on the Saaty’s scale according to their virtual significance in groundwater incidence. The assigned weights of the thematic layers and their features were then normalized by using AHP. Finally, the selected seven thematic maps were incorporated by weighted linear combination method in a GIS environment to produce a groundwater target map.

Abstract

As the available surface water is too inadequate to fulfill the man’s requirements he was forced to locate newer groundwater reservoirs on one side and to control the fast depleting water table on the other side. As the ancient techniques have failed to give precise models on groundwater targeting, he was to invent and employ newer technologies. Under this scenario the recently invented spatial technology has emerged as a very powerful tool in groundwater targeting and management. The vistas and virtues of such spatial technology in groundwater management have been discussed in this overview paper by citing some case studies from Tamil Nadu, India.

Abstract

In South India, tanks system is quiet ancient, meant for storing and supplying water towards multifunctional needs of the people. In Tamil Nadu, there are around 39,000 tanks with varying size and types. Over past few decades, irrigation rely on stable and reliable groundwater resources like dug and deep bore wells, consequently tanks lost their significance. Moreover, excessive siltation, improper maintenance and illegal encroachment further degraded the system. The deterioration factors are broadly categorised into problems in catchment, feeder channels and head works which eventually resulted in loss of storage capacity. The present study chiefly narrates an indirect method of estimating the loss in storage capacity of tanks and the catchment problem, especially soil erosion and its induced siltation of tanks in the downstream using geoinformatics technology. Using remotely sensed satellite data, by measuring surface area of tank loss in storage capacity was estimated through a linear model. Using Digital Elevation Model derived topographic wetness indices data, the catchment problem especially, soil erosion areas were identified and remedial measures were suggested. Under prevailing water crisis, it is essential to rehabilitate the tanks through which the surface water potential can be improved along with quality as well.

Abstract

Water is an essential and vital component for our life support system. Drought and floods are the extreme events of rainfall and the vagaries of monsoon and hydrogeological framework in the country are highly variable from place to place. The water resources available in the country are also not uniformly distributed. The changing Landuse pattern and population growth and the resultant water resources development has lead to water stress at many places. In such areas, the extraction of excessive quantities of groundwater has resulted in the drying up of wells, damages of ecosystems, land subsidence, salt-water intrusion and other related problems. Agricultural, urban & industrial wastes are increasingly threatening the groundwater quality, which is likely to become a more serious issue in the coming years. Considering the seriousness of the groundwater contamination, Central Ground Water Board has carried out detailed studies in few hot spots in the state of Tamil Nadu. The issues related to the water resources contamination and the findings of the studies in parts of Tamil Nadu are summarized in this paper.

Abstract

The Tamil Nadu is one of the leading states in groundwater development. Since the surface water resources have been fully exploited for irrigation, the groundwater is massively mined for agriculture, domestic and industrial purposes. The paper provides a synthesis of whole groundwater related issues including basin wise groundwater conditions, the aquifer types, geogenic water quality and quality deterioration due to anthropogenic activities, need for recharge, the utility of Remote Sensing & GIS etc. The paper has come out with set of recommendations as the concluding remarks.

Abstract

The state of Tamil Nadu has a low easterly gradient slope and there are number of rivers, big and small originate from the west flow towards east south easterly and confluence the Bay of Bengal. These were grouped into seventeen major and minor river basins, the Cauvery being the largest basin and the river is also a near perennial river. These river basins receive rainfall both from the southwest and northeast monsoons. The state has over 40,000 surface water bodies and number of major dams and reservoirs. Even then, since the rainfall of the north east monsoon, the major source of water source to these basins, occurs in short span of few days with high rainfall, neither adequate storage is there to store them nor the recharge possibility is available, thus all leading to flooding and wastage. The 40,000 and odd water bodies are heavily silted and polluted too. The paper provides an over view of all these, basin wise, and in addition, strongly advocates intra state river linkage and improvised irrigation management as the best option to save the state from its water deficiency.

Abstract

The Mesozoic sediments contribute around 54% of the oil and 44% of the gas reserves of the world (Bois et al. 1982). Indian Mesozoic basins occupy an area of about 400 x 103 sq. km and are characterized as frontier basins under category II - IV. These basins are mostly overlain by the Deccan Traps of Late Cretaceous age and are least explored. Deccan Syneclise is one of the largest Mesozoic basins in India, covering an area of ~ 273 x 103 sq. km. Geophysical studies have inferred hidden sub-trappean Mesozoic sediments with thickness up to 2.5 km. It is considered that requisite heat generation due to Deccan Trap volcanism soon after the Cretaceous sedimentation may have acted as a catalyst in hydrocarbon generation. Surface geochemical prospecting surveys along with carbon isotopic studies have been used to assess hydrocarbon generation potential of this part of the basin. The area adjoining Nandurbar beneath Narmada-Tapti region of Deccan Syneclise was selected for geochemical studies where geophysical studies have shown considerable sediment thickness. Surface geochemical studies indicate the generation of light gaseous hydrocarbons, C1 and SC2+ in the range of 3 to 1187 ppb and 1 to 1449 ppb, respectively. The carbon isotopic signatures of selected soil gas samples dC13 CH4 in the range of - 24 to -39.4‰ PDB) suggest thermogenic origin

Abstract

Sabatayn basin is one of the two mature basins producing oil and gas in Yemen. Due to the recent decline in oil production, the exploration activities have been extensively concentrated mainly on these two basins (Sabatayn and Sayun-Masilah). So, this present study has been conducted to evaluate the exploration potential of the remaining trap areas within these mature basins. Fractured basement of reservoir becomes very attractive exploration target in Yemen recently, after the recent discoveries of basement fractured oil fields. As the evaluation of basement traps needs time and fund, to reduce the same, this research study uses a new technique which was devised with the help of Geoinformatics by analyzing the surface and subsurface lineaments effectively. In this study, a satellite image Enhanced Thematic Mapper (ETM+7) based analysis was conducted for extracting surface lineaments, and for the subsurface lineaments, the basement lineaments were extracted from seismic, magnetic and gravity data. An orientation analysis of these surface and subsurface linear features was performed to detect the basic structural grains of the study area. The correlation between these structural grains and subsurface oil and gas traps was performed to understand the connectivity to the reservoirs. This paper discusses in detail about the same and the importance of using surface and subsurface lineament analysis for delineating hydrocarbon reservoirs in the study area.

Abstract

The Pudukkottai district located in the southeastern tip of Tamil Nadu, India provides a complex geological setting with three litho-tectonic blocks membered by the hard Crystalline rocks of Archaeozoic-Proterozoic Era in the west,Mio-Pliocene Sandstone/Cuddalore Sandstone in the centre and Quaternary sediments in the east. While the western and central blocks are separated by a well-defined NNE-SSW trending fault, the central Mio-Pliocene Sandstone block is cut into two parts by a N-S fault with western static block and the eastern uplifted counterpart. Besides the above, the various drainage anomalies viz; Annular, Deflected and Eyed drainages and compressed meanders interpreted using the raw and digitally enhanced satellite multispectral data show that the N-S oriented faults with oscillations from NNW-SSE to NNE-SSW, NE-SW and E-W orientations are tectonically active in the area. The integration of these active faults with known geothermal springs and the maxima axes drawn from the contours deducted from the temperature of groundwater measured during the predawn hours from the wells revealed that the N-S and NE-SW faults are the probable locales for geothermal resources in the study area. Thus the study demonstrates a newer methodology for locating the geothermal prospects.

Abstract

The emergence of Remote Sensing and GIS technologies has substantially eased the problems of groundwater targeting in hard rock aquifer systems. Proper utilization of these can provide more vital information in managing such scarce resource. In this context, a new technique of GIS based visualization of groundwater levels of different periods (1985- 1990 -1995) was attempted for a part of Western Ghats hill-plain region of Tamil Nadu and various groundwater features viz: ridges, valleys, domes and basins were interpreted. The integration of such groundwater features of different periods and their analysis with structural features provided some newer information on geosystem processes and their interface dynamics with hydrosystems, from which, certain strategies were suggested for better groundwater management in hard rock areas.

Abstract

The study area falls in the southern part of the Indian Peninsular comprising hard crystalline rocks of Archaeozoic and Proterozoic Era. In the present study, the GIS based 3D visualizations of gravity, magnetic, resistivity and topographic datasets were made and therefrom the basement lineaments, shallow subsurface lineaments and surface lineaments/faults were interpreted. These lineaments were classified as category-1 i.e. exclusively surface lineaments, category-2 i.e. surface lineaments having connectivity with shallow subsurface lineaments and category-3 i.e. surface lineaments having connectivity with shallow subsurface lineaments and basement lineaments. These three classified lineaments were analyzed in conjunction with known mineral occurrences and historical seismicity of the study area in GIS environment. The study revealed that the category-3 NNE-SSW to NE-SW lineaments have greater control over the mineral occurrences and the N-S, NNE-SSW and NE-SW faults/lineaments control the seismicities in the study area.

Abstract

The strenuous field trekking, inaccessibility, perception of geology only within the visibility range of the eyes etc. have remained matters of major constraints in the past in field based geological mapping. The remote sensing technology not only eradicated these but also provided lot many newer vistas in the field of geology. In addition, the application of such unique technology has brought out a hierarchy of newer concepts in the field of geology. The paper narrates the newer knowledge gathered on the geology of South India in the post remote sensing Era.