eChapters

ABSTRACT

Bats: A colony of 500 insectivorous bats of Hipposideros speoris inhabited a natural cave in Madurai (9^O58’ N. lat; 78^O10’ E long). At a depth of 40 m, the cave experiences a constant temperature of 27 + 0.1^OC, 95 % relative humidity and absolute and perpetual darkness. Therefore there were no day/night cues. Yet all the members of the bat colony flew out 10 to 15 min. after sunset as though they knew the time of sunset. Recorded flight and rest experiments in flight activity cages and a hand-wound Thermohygrograph drum 40 m from the cave mouth over periods of 50 days revealed that the free-flying conspecific bats were socially synchronizing the activity patterns of the three captive bats. Bats were telling other bats time.

Mice : In the field mouse, Mus booduga the mother conveys information of day and night to her pups by means of her presence and absence (PA) cycles. Her presence meant day and absence denoted night. We named this phenomenon maternal entrainment. Such entrainment of the time sense of the pups was possible if in every cycle the mother was presented for a minimum of 8 hr but not exceeding 16 hr. Therefore 8 hr and 16 hr describe the limits of maternal entrainment.

Botany

The plant is highly cross pollinated due to heteromorphism and bees being the major pollinators.

Varieties: PKM 1 & PKM 2

Method of seed production : Seed to Seed.

Land requirement : Uproot all the wild and non specific moringa trees if any near the field within a radius of 1500ft. Good drainage facility is must for moringa.

Isolation requirement : A distance of at least 500 M is necessary for seed production.

Season : Early season (July August), Mid season (September), Late season (October -November). Best season is September October, so that flowering starts during summer which facilities better pollination and seed set.

Abstract

The landslides of the hill ecosystems are either due to the natural morphotectonic and morphodynamics processes of the planet earth or due to the anthropogenic effects or due to the combinations of the both. In the Indian subcontinent, the landslides are reported from three major provinces viz: Himalayas, Westernghats and The Nilgiris. While the landslides of the Himalayas are demonstrated to be predominantly due to active tectonics, the landslides of the Westernghats are attributed to excessive weathering and rock fall. On the contrary the landslides of the Nilgiris have been thought to be due to extensive deforestation and the related increase in the pore pressure during rainy seasons. But the studies carried out in the recent years show that not only in the Nilgiris but also in other hill systems of Tamil Nadu, the landslides seem to be related to the recent earth movements. This is very significant in the context of fastly recurring seismicities in South India and hence this aspect warrants detailed studies for landslide mitigation.

Abstract

The analysis of IRS - 1A satellite imagery has indicated the existence of two NE - SW trending sub parallel faults along which the coast is undergoing land subsidence as revealed by the concavity in the shore line, preferential migration of the river systems and the drainage congestion, absence of beach ridges, occurrence of off shore shoal etc. The study has further indicated chains of tectonically induced environmental problems such as ground water logging, coastal zone flooding, storm surges, harbour sedimentation etc.

INTRODUCTION

Coastal zones are always dynamic and active, because of the multivariate morpho tectonic and morpho dynamic processes, viz: tectonic, fluvial, marine and aeolian which act in varying degrees and duration along the coasts. As these geomorphic / morpho dynamic processes act in varying permutations and combinations in different segments of the coasts, the land - ocean interactive phenomenon vary greatly in time and space, which in turn frequently and dynamically alter the coastal environment, and cause fragility to the coastal ecosystems. Further, as the coastal zones act as the junction between the Continents and the oceans, even mild earth movements exhibit exemplified expressions in land - water distribution pattern along the coasts. The green house effect and the much apprehended sea level rise and the disasters like cyclones also contribute in their own way in accelerating such land - water distribution / land - ocean interactive phenomenon.

OBSERVATION

The examination of the IRS - 1A imagery under raw and the digitally enhanced modes vividly display heavy concentration of suspended sediments in certain sectors along the east coast of Tamil Nadu. Such pockets of suspended sediments are seen as long and linear bodies trending parallel to the coast to the strike length of 20 - 30 km and width of 5 - 10 km. Such Phenomenon of suspended sediments concentration are strikingly observed in two sectors. One in between Tuticorin harbour and Vaippar river mouth and the other just at the mouth of Ponnaiyar river along Cuddalore-Pondicherry coast. Both of them are observed along conspicuous (Fig.1& 2) concave coasts.

The resources on the land have started showing sign of faster depletion owing to the population explosion, over exploitation of mineral and water resources and also the improper exploitation and the related wasting of the natural resources. Hence a time has come to search for more and more newer natural resources amongst which the ocean resources gain supreme importance as this treasure is yet to be hunted due to the non - availability of suitable technology for the same.

Such ocean resources mainly include the mineralogical and biological resources. The ocean biological resources, their birth, growth, population and migration greatly depend as chlorophyll content, total dissolved oxygen, total suspended solids, salinity etc. These parameters which constitute the marine environment drastically change in a quick span of time owing to the dynamically changing marine forces.

Abstract

The present study has revealed that the NE-SW and WNW-ESE trending sinistral faults are very active along the Tamil Nadu coast and the same have caused considerable slope modifications along the Coleroon and Karungalar rivers which are well-manifested in the land, water and mudflat distribution pattern. Similarly, the progradation of the land in Vedaranniam nose is due to the rise of Pattukottai-Mannargudi area and the time transgressive modifications of the Vedaranniam backwater indicates the opening up of the N-S trending Pleistocene-Holocene faults.

Abstract

The art of remote sensing has opened up many vistas in the study of river migration as satellite photographs, both in their normal and digitally enhanced modes, vividly show the rivers and their migratory signatures. The rivers migrate for various reasons amongst which tectonic movement is one of the main causes. In the present study an attempt has been made to exhibit the palaeochannel network of the rivers of Western India and integrate them with lineament fabric, so as to understand the Quaternary tectonics of the region. The study has shown that Western India shows considerable signs of Quaternary tectonics.

The great Indian epic ‘Ramayana’ says that ‘Lord Rama’ has tried to cross over the Bay of Bengal so as to reach Sri Lanka from India from three points along the southeastern fringe of the Indian coast. Firstly, he is said to have tried to cross from Vedaranniyam which is mythologically called as ‘Kodiyakkarai’ Secondly from Manamelkudi and finally crossed over to Sri Lanka from Rameswaram Island (Fig.1), as the former two coastal locations were widely separated from Sri Lanka by Bay of Bengal and the Rameswaram Island was nearer to Sri Lanka during that period. But, the recently acquired satellite data shows the huge accretion of sediments and rapid land building activity off Vedaranniyam coast (Fig. 2 and 3). The geomorphic interpretations carried out using IRS 1A imagery and 14^C archaeological dating of such geomorphic features have shown that such ongoing sediment accretion phenomena off vedaranniyam nose might in future connect the Vedaranniyam part of Indian Peninsula with Jaffna Peninsula of Sri Lanka if the sediment accumulation continues unabated. The sediment accretion in this area, therefore, requires detailed studies particularly in the context of the coastal ecosystem (Fig. 1).

Abstract

The Remote Sensing and the followed up field based investigations show that the Tamil Nadu coast, India, is facing series of geoenvironmental problems due to tectonic movements and morphodynamic processes. Such problems pose a challenge to the engineering geologists. The paper discusses such challenging engineering geological problems and plausible remedial measures.

Abstract

The tectonic and the geomorphic features observed along the west coast of the area between Mangalore and Cape Comorin show that the NNW-SSE trending west coast has been carved out by the Western Ghats orogeny and the related NNW-SSE trending release fractures. The sinuosity of the otherwise straight coast line is due to Quaternary cymatogenic arching caused by the thrust related to the northerly movement of the Indian plate. The coast line has further attained peaks, projections and serrations due to the ENE-WSW trending series of Precambrian extension fractures which were reactivated gaining the northeasterly directed forces from the rising Carlsberg ridge. Overall, the west coast is being tectonically evolved even today due to the rise of Carlsberg ridge and the Indian plate movement.

Abstract

There is a consensus amongst the geoscientists that overall there has been progradation along the east and west coasts of peninsular India. However, the present day configuration of the coasts and some of the geomorphologic features such as absence of spit and delta along west coast and absence of major estuaries and petroliferous structures along east coast still remain controversial. The present study, based on the appreciation of certain geomorphological and tectonic features on Landsat imagery and aerial photographs of southern part of Indian Peninsula, suggests that the evolution of the coastline has been mainly controlled by tectonism.

The tapering nature of the coastline is attributed to the Precambrian orographic axis. The serrated nature of the post Precambrian coast line is due to the Precambrian transverse faults, whereas the serrated margin of the post Gondwana, Post cretaceous and post Tertiary coast lines are attributed once again to the Precambrian faults reactivated time and again. During the Quaternary period the coast line has undergone many modifications. The coast line attained sinuosity due to Pleistocene folding which is well manifested by river migration. The coast line was subsequently faulted and shifted with en echelon pattern due to N-S regional compression which is referable to the collision of Indian Plate with Tibetan plate.

Amaranth is an annual herb with erect growth and scarce to profuse branching habit. Flowers are borne terminally and in axils of leaves in clusters. Basic unit of inflorescence is called as glomerule. Flowers are small, unisexual and monoecious. Proportion of male and female flowers varies in an inflorescence. Each glomerule consists of a staminate flower and a number of pistillate flowers. The extent of cross pollination is governed by proportion of male and female flowers in an inflorescence and position of inflorescence in plant

Onion is one of the oldest cultivated plant species. Onion forms the bulb in the first year and the seed in the second year. The leaves arise from a shortened crown stem. The sheaths of the older or outermost leaves enclose the younger ones. The basal portion of the leaves encircles the stem, and thickens to form the bulb. The stem elongates during the second year forming the flower stalk. The onion has a fibrous root system extending to a depth of over one meter, but most of them are found in upper surface about one-half meter area.

Remote sensing has proved its credibility beyond doubt in natural resources survey and environmental monitoring owing to its synoptivity, multispectral photographic capability and repetitive coverage. While its synoptivity gives unbiased information on the regional panorama of the earth surface, its multispectral possibility aids precise interpretation of various objects, as different terrestrial objects exhibit various spectral responses in different bands of the electromagnetic spectrum. Amongst various terrestrial objects, water has a characteristic spectral response of its own, i.e. it permits the blue / red part of EMR (electromagnetic radiation, 0.4-0.8 µm) to penetrate inside. On the contrary, it totally absorbs the infrared part of EMR (0.8-1.5 µm). As such blue/red part of EMR penetrates the water bodies, the impurities and suspended sediments are seen very clearly in various shades of gray as and when the water bodies are shallow. Many workers, therefore, have used blue / red band of the satellite data in such water-quality studies^l-3. Hardy⁴ has observed that the infrared light in the spectral regions of 0.6-1.4 µm has the potential to map the turbidity in the ocean water, whereas Kritakos et al ⁵ have used the rationed data of visible and near infrared bands (0.4-1.1 µm) and obtained better results for water quality monitoring. Keeping such facts in mind, the blue/red band (band 2) of the IRS 1A satellite data was used to configurate the bathymetry along Madras coast in Bay of Bengal (Figure 1 a).

In the present study, the IRS lA band 2 data (0.52-0.59 µm) of March 1991 was used and subjected to edge enhancement studies for the coastal zone of Madras (Figure 1 a). Such edge enhancement normally sharpens the edges of two contrasting objects or sharpens the edges of objects of contrasting relief. In such edge enhanced data, few

Pumpkin (Cucurbita maxima Duch.) is a well known and widely cultivated vegetable variety of the family Cucurbitaceae. The seed production can be done in summer season (February - March) and in rainy season (April - May). In Tamil Nadu, sowing during July – August is best for seed production.

Botany: Bottle gourds belonging to the family cucurbitaceae is an annual vine having white flowers and smooth, large, hard-shelled gourds. Brownish seeds are numerous in a whitish green pulp. Each seed is somewhat rectangular in shape with grooved notches near the attached end. Grown most often in warmer climates, this squash grows from 6 to 36 inches long and 3 to 12 inches in diameter.

Seeds leaves, flowers and young stems are all edible. Helpful in shedding extra calories. It contains higher concentrations of Dietary Fiber, Vitamin A, Vitamin C, Vitamin K, Vitamin B6, Folate, Potassium, Manganese, Protein, Vitamin E, Thiamin, Riboflavin, Pantothenic Acid, Calcium, Iron, Magnesium, Phosphorus and Selenium. A rich source of minerals and vitamins, bottle gourds contains many healing and medicinal properties. The cooked vegetable is not only easy to digest but also contains cooling, calming (or sedative), diuretic properties. It contains low calories also has iron, Vitamin C and B complex. Regular consumption of this vegetable provides relief to people suffering with digestive problems, diabetics and convalescents.

Botany:Snake gourd belonging to the family Cucurbitaceae native to Southeastern Asia and Australia but cultivated throughout the world for its curved and oddly shaped fruits that appear like snakes hanging on the supports or ground. This subtropical plant grows very fast in warm climates and produces lots of fruits for a long time. It is suitable for growing for home garden and fresh market.

Climate and soil: Snake gourd is adapted to wide variety of soil and climatic conditions. It requires a minimum temperature of 18^oC during early growth, but optimal temperatures are in the range of 24–27^oC. Snake gourd tolerates a wide range of soil but prefers a well drained sandy loam soil that is rich in organic matter. The optimum soil pH is 6.0–6.7, but plants tolerate alkaline soils up to pH

Varieties: CO1,CO2, PKM 1, PLR 1 and PLR 2.

Pulses can be grouped into kharif and rabi pulses according to their temperature requirements. In India chick pea, pea, lentil and beans require relatively less temperature and are grown in rabi season, whereas others are confined to kharif season. However, kharif pulses can also be grown in pre-rabi on stored soil moisture or as irrigated crops in rabi and summer seasons.

Pulse crops have long tap root system which extracts soil moisture from deeper layers. Water uptake across the depth of rooting zone is not uniform. In general 40 per cent of the total water uptake occurs from first one fourth of the rooting zone, 30 per cent from the second, 20 per cent from the third and remaining 10 per cent from the last one-fourth region of total rooting depth (Nageshwararao and Writ, 1994). Plants often maintain higher root length densities than required in the surface layers to facilitate rapid uptake of recent rain/irrigation before it evaporates.