eChapters

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.

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

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.

Pulses are known for their soil fertility restoration value. Deep rooting, nitrogen fixation, leaf shedding ability and mobilization of insoluble soil nutrients are some of the unique characteristics of pulses. By improving chemical, biological and physical environment in the soil, pulses can arrest the declining trend in productivity of cereal-cereal system. Inclusion of pulses in intensive cereal based system itself is a component of integrated plant nutrient supply system. Therefore, pulses have become viable alternative to improve the soil health and conserve the natural resources and agricultural sustainability. Pulses in the cereal/oilseed based cropping systems are introduced to break the monotony of crop rotation. Pulses being rainfed low input crop provide safeguard against crop failure due to scanty rainfall and adverse weather conditions. Apart from enriching soil fertility, introduction of pulses in cropping system also improves nitrogen economy. Early pigeonpea-wheat sequence was evaluated and found promising than traditional rice-wheat cropping system in irrigated areas of Punjab, Haryana, central and western Uttar Pradesh.

Pulses are legumes whose grains are consumed as dal. Thus all legumes are not pulses, but all pulses are legumes. Legumes are characterized by presence of nodules in the root systems and papilionaceous form of flowers. Pigeon pea [Cajanus cajan (L.) Millisp.], green gram [Vigna radiata (L.) Wilczec.], black gram [Vigna mungo (L.) Hepper], cowpea [Vigna unguiculata (L.) Walp.], horse gram[Macroyloma uniflorum [(Lam.) Verd.] and moth bean[Vigna acontilifolia (jacq.) Marechal] are the important kharif pulse crops grown in different parts of India. The common rabi pulses are chickpea(Cicer arietinum L.), lentil (Lens culinaris Medik.), pea (Pisum sativum L.), lathyrus (Lathyrus sativus L.) and frenchbean ( Phaseolus vulgaris ). All these have C₃ photosynthetic cycle. All form root nodules in association with symbiotic bacterium Rhizobium. Increase in concentration of green house gases, particularly carbon di-oxide, has led to global warming and climate change. The extreme weather events such as drought, excess moisture, untimely rain, cyclone, excess heat and hailstorm have become common. Crops respond differently to increase in CO₂ concentration. Both abiotic and biotic stresses due to global warming are likely to reduce productivity of pulses/pulse based cropping systems through adverse effects on crop growth and development. Birthalet al. (2014) reported higher decrease in grain yield of pulses(pigeonpea and chickpea) as compared to cereals (rice and wheat) due to rise in the minimum and the maximum temperature.

Introduction

Pulses are pivotal and integral component of Indian agriculture and are excellent crops for natural resources management, environment security, crop diversification consequently for viable agriculture. India contributes 25 percent of the global production but has to import pulses to the home to the tune of 3.5mt every year to meet domestic requirement. In spite of largest area for chickpea, pigeon pea, lentil, dry beans & total pulses in the world, India’s’position in average productivity has never been decent i.e.25^th rank in chickpea, 19^th in Pea & 98^th in total pulses. This indicates that except chick pea & pigeon pea, the average productivity of the country is significantly lower than average yield of the world. To make India self sufficient in pulse production, the productivity level has to increase more than1200 kg/ha. by 2020. This gigantic task needs rigorous development & promotional efforts to transfer agro-technology packages in crop improvement and crop management, which are capable of doubling the present level of productivity Nanda et al. (1999) and Nanda

Technologiocal intervention is essential for improving pulse productivity through introduction of suitable high yielding varieties (Masood Ali and Shiv Kumar 2009). This is only possible through: (i) development of high yielding varieties with multiple resistance/tolerance to major diseases like mung bean yellow mosaic virus (MYMV), powdery mildew (PM) and Cercospora in mung bean and urdbean; (ii) development of varieties having resistance and tolerance to pre-harvest sprouting in mung bean, (iii) development of efficient plant type with high biomass and harvest index, (iv) development of varieties suited for intercropping system, (v) broadening genetic base of developed varieties, (vi) development of 50-55 days varieties of mung bean having 1 tonne/ha productivity and resistance to YMV for summer cultivation, (vii) development of high yielding and early maturity varieties of peas having resistance to powdery mildew, (viii) developing rajmash genotypes resistant to bean common mosaic virus and sclerotia rot, tolerant to high/low temperature and shattering resistance are important ones for increasing production through varieties intervention (AICRP MuLLaRP, http://iipr.res.in/mullarp).

Pulses are gaining more important position in Indian agriculture. After green revolution, India became self sufficient in case of food grain production. However, India is still lagging behind in case of pulses production and is dependent on imports for the domestic consumption in present days. As there is little scope to increase area under pulse, the production can be increased by enhancing the productivity by various agro techniques. Among various factors which limit the pulse production and productivity, poor weed management at the early stages of crop growth, is one of them( Dash et al., 2003 and Dash & Mishra, 2014). Yield loss due to weed have been enumerated by different workers at different places to the tune of 20-65 per cent depending upon the crop growth stages, weed intensities and environment conditions. There are many methods available to control the weed menace at different crop growth stages but the integrated weed management (IWM) is considered to be a more practical and effective approach in the long run since combination of methods will take care of weeds in totality and prevents seed production of weeds and enrichment of soil seed bank (Das, 2008). IWM also provides continuous control of weeds over the crop growth stages than a single method in isolation. Hence application of suitable organic herbicide supplemented with one/two manual weeding are being advocated to control the weeds. Other weeding practices like hoeing, inter- cultivation, mowing, earthing up, weeding by mechanical weeder etc. may be substituted or supplemented to the manual weeding. IWM also reduces the modern day weed problems like weed shift, herbicide resistance, and preponderance of perennial and parasitic weed problems. Under high cropping intensity adoption of IWM practices always generate higher income and maximum profit to the growers.

Abstract

The East Coast of Tamil Nadu exhibits a spectacular network of deltas formed by the easterly flowing river systems. The study of raw and digitally enhanced Landsat TM and IRS data shows, that these deltas were formed due to multivariate dynamic processes of fluvial, marine and aeolian actions. The wide fan shaped delta observed northwest and north of Madras city spanning out over an area of 700 sq.km is a feature, standing testimony to the PaleoCauvery river systems.

The regional slope and the overall arcuate arrangement of the crescent shaped lakes in the area and the tentacles of paleochannels show, that it is overall a fan shaped delta and its successive growth towards the sea might have been due to the constant progradation of lobes by continuous reworking of preceding lobes. The depressions in between successive concentric lobes have become the lakes. The absence of any beach ridges in such palaeo deltaic regime suggests that, it would be a sub aerial delta only. The overall arcuate shape of the shoreline in between Madras city in the south and Pulicat lake in the north is due to this fan delta. This feature once again symbolises the active river dominated delta. The Palar delta is a ‘cuspate’ one. The Ponnaiyar river has developed a linear delta, along a narrow depression found in between Tertiary uplands. While the avulsion phenomenon indicates the ancient shoreline near Villupuram, the east-west trending micro sandy uplands within the delta suggest, that it is a tide dominated delta.

Abstract

Satellite photographs depict exciting evidence on the migratory melodrama of river systems. A study has been conduced in parts of Tamil Nadu using IRS-IA Satellite pictures, archaeology and Tamil literature, which reveals that from Pleistocene to 2700 years B.P.(Before Present) the river Cauvery flowed in a northeasterly direction from the Stanley reservoir via Chinnar, Palakkodu, Mattur, Tiruppathur (Tiruppattur), Gudiyatham (Gudiyattam), Vellore and Walajapet to meet the sea at Madras. From 2700 to 2300 years B.P., it flowed via Uttangarai and Tirukkovilur to meet the bay of Bengal near Pondicherry, over which the present-day Ponnaiyar is a misfit stream . From 2300 to 1300 year B.P. it has flowed via Erode, Tirukkampuliyur, Alagarai , Tiruchy, Kiranur and Pudukkottai meeting the sea in the region where the present-day Agniar and Ambuliar meet the sea. Subsequently, between 1600 and 1300 years B.P., the Cauvery flowed along the present-day tracts of the Vennar and Vettar, after which it seems to have flowed as the Kodamurutti, Arasalar and PalanCauvery from 1300 to 1000 years B.P. From about 900 years B.P. it flowed via Tirupurampayam (Tirupurambiyam), Achalpuram till around 750 years B.P. and then it is stabilised as the Colleroon (Kollidam). Such periods and phases of river migration as well as their implications in the search for archaeological remains are discussed in this paper.

Much has been talked about the mighty river systems and their migratory histories, since Purana and Vedic times. In Mahabharata the places where the Lord Krishna is said to have played with Gopis in the banks of River Yamuna are now forming flat lands many kilometers away from the present day Yamuna. In the same way, there is a mention in ancient literature about the ‘Indo-Brahm’ river which was originated from the Himalayas and flown through Brahmaputra valley, Indo-Gangetic plains, Rajasthan desert and met the Arabian Sea in Rann of Kutch. Such a mighty river is said to have fragmented into Brahmaputra, Ganges and the Indus rivers due to Tectonic activity in Himalayan regions. Similarly there are many evidences in the Tamil literature. For example in ‘Kalingathuparani’ it is mentioned that the river ‘Palar’ was flowing north of Kanchipuram but the same river is now flowing south of it.

All these facts show that the rivers have the tendency to frequently change their courses. The advent of modern Remote Sensing Technology has opened up new vistas in studying such migratory rhythms of the rivers, as such old and buried rivers exhibit spectacular ribbon like, linear, curvilinear and contorted features with typical darker tone in black and white images and reddish tone in false color composites (FCC) and other color coded images.

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.

Abstract

The anomalies observed in the reverine systems have been demonstrated to be the potential tool in deciphering the tectonically active zones. Such various drainage anomalies viz: radial drainages, anomalous compressed meanders, eyed drainage and the youthful floodplains observed in Annamali – Palani - Varushanad hill ranges of the Western Ghats of Tamil Nadu show that the N-S and NE-SW trending faults are tectonically active in the recent years.

Abstract

It has been established beyond doubt that the drainage architecture and the fluvial histories of river systems give excellent indications not only on the surficial lithology but also on the ongoing morphotectonic processes of the planet earth. Among the various drainage patterns, the ‘eyed drainage’ pattern is considered to be one of the most significant anomalies and such ‘mega eyed’ drainages interpreted from IRS-IA imagery in some of the major river systems in Tamil Nadu, Indian Peninsula, are found to signify ongoing tectonic movements in an otherwise seismically inert shield area.