eChapters

Introduction

Arid lands are among the world’s most fragile ecosystems, made more so by periodic droughts and increasing over exploitation of meagre resources. Arid and semi-arid lands cover around one-third of the world’s land area and are inhabited by about one billion people, a large proportion of whom are among the poorest in the world (Malagnoux et al. 2007). Arid environments are extremely diverse in terms of their land forms, soils, fauna, flora, water, and human activities. Aridity is usually expressed as ratio of mean annual precipitation (P) to the mean annual potential evapotranspiration (EPT) where potential evapotranspiration is calculated by method of Penman, taking into account atmospheric humidity, solar radiation, and wind speed. UNEP (1997) has recognized four main classes of aridity: hyper-arid (P/EPT < 0.03), arid (0.03 < P/EPT < 0.20), semi-arid (0.20 < P/EPT < 0.50), and dry sub-humid (0.50 < P/EPT < 0.65). Of the total land area of the world, the hyper-arid zone covers 4.2 %, the arid zone 14.6 %, and the semi-arid zone 12.2 % (FAO 1989). Therefore, almost one-third of the total area of the world is “arid land”. 

Introduction

There is a growing interest in the role of different types of land use systems in stabilizing the atmospheric CO₂ concentration and reducing the CO₂ emissions or on increasing the carbon sink of forestry and agroforestry systems. Forestry has been recognized as a means to reduce CO₂ emissions as well as enhancing carbon sinks. There is considerable interest to increase the carbon storage capacity of terrestrial vegetation through land-use practices such as afforestation, reforestation, and natural regeneration of forests, silvicultural systems and agroforestry (Brown 1996; Canadell and Raupach 2008). Agroforestry systems are very important given the area currently under agriculture, the number of people who depend on land for their livelihoods, and the need for integrating food production with environmental services (Garrity 2004; Makundi and Sathaye 2004).

Introduction

The literatures and researcher data showed that there is negative impacts of agricultural expansion, landscape modification and deforestation on biodiversity, ecosystem services, alteringthe species composition and their ecological functions (Tscharntke et al. 2005; Priess et al. 2007; Flynn et al. 2009; Senior et al. 2013; Deguines et al. 2014; Kumar 2016) which can lead to considerable changes in critical ecosystem processes. On the other hand, an increasingly industrialized global economy, rapid population growth, land degradation, land use pattern and role of various human activities have led to dramatically increased the pressure on the natural resources such as the available land for sustaining the livelihoods, and with over exploitation and extraction of the natural resources the ecosystems are becoming unsustainable and fragile since last century (Kumar 2017). Standardization of cultural practices is one of the primary objectives to make the system ecologically, sustainable and economically viable (Gill et al.2009).

Introduction

The vast majority of climate change impacts and the overall impact of climate change on rice production are likely to be negative. Overwhelming scientific research and evidence have shown that the climate is ongoing. According to the International Food Policy Research Institute (IFPRI) report Climate Change: Impact on Agriculture and Costs of Adaptation forecasts there will be an increase in the net price of rice between 32 and 37% as a result of climate change by 2050. They also show that yield losses in rice could be between 10 and 15%. While there is still ongoing scientific exploration into climate change, IRRI recognizes two universal trends predicted by all climate change models viz., temperatures will increase, resulting in more heat stress and rising sea levels and there will be more frequent and severe climate extremes.

Introduction

Arunachal Pradesh is the largest hill state of North Eastern Himalayan Region having the total geographical area of 83,743 Sq Km, stretching between 26o28’ to 29o28’ N latitude and 91^º35’ to 97^º27’ E longitude and is endowed with a unique geo-physiography. Topographically, Arunachal Pradesh is generally a hilly region, with entire state lies on the mighty Himalayan and Patkoi ranges. The elevation of the hills ranges from 60 meters to over 7000 meters. Mt. Kangto (7090 m), Mt. Nyegi Kangsang (7050 m) and Mt. Gorichen (6488 m) are three highest peaks of Arunachal Pradesh. The Himalayan mountain system divides the state mainly into five river valleys: the Kameng, the Subansiri, the Siang, the Lohit and the Tirap. These rivers, along with innumerable rivulets traversing through innumerable hill systems treading through the rugged terrains, steep hills, valleys and ultimately drain down to from two major river systems and valleys of the region__ the Brahmaputra and the Barak. The state has rich biological as well as cultural diversity.

Introduction

Climate is a measure of the average pattern of variation in temperature, humidity, atmospheric pressure, wind, precipitation and other meteorological variables in a given region over long period of time. Climatic change refers to the shifts in the mean states of the climate or in all its variability, persisting for an extended period (decade or longer). The expected climatic change includes an increase in average temperature, an increase in CO₂ concentration and varied rainfall regimes due to increased ultra violet-B radiation. Fossil fuel burning and deforestation have emerged as principal anthropogenic sources of rising atmospheric CO₂ and other greenhouse gases and consequent global warming and climatic change.

Introduction

ICT is an acronym for Information and Communication Technology.  The information refers to accessibility of digital data in an easy way to retrieve relevant facts. The communication refers to the medium or the way to transmit the information from one place to another place or one media to another media. The advancement in these areas refers to technology. The collectively ICT covers any product that will store, retrieve, manipulate, transmit or receive information electronically in a digital form. For example, personal computers, digital television, email, robots.

Climate change may refer to a change in average weather conditions, or in the time variation of weather around longer-term average conditions (i.e., more or fewer extreme weather events). The change lasts for an extended period of time i.e., decades to millions of years has also been considered as climate change. The causing factors of climate change are biotic processes, variations in solar radiation received by Earth, plate tectonics, and volcanic eruptions. The affecting factors seems to be irreversible, it has become the today’s necessity to develop improved next generation technologies which processes the current and future shifts in the climate system. In particular, the Agriculture will be most affected domain due to climate over the next few decades (Brown and Funk, 2008). The development of crop modeling tools pointed out that climate change is likely to decrease agricultural production.

Introduction

Greenhouse gases (GHGs) are the atmospheric trace gases which absorb and emit infra-red radiation and thereby trapping the heat radiated from the earth surface. The commonly known agriculturally important GHGs are carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O). The major anthropogenic sources of CO₂ emission in atmosphere are biosphere, burning of fossil fuels and land use changes in tropical forests. The atmospheric concentration of CO₂ has increased from 280 parts per million by volume (ppmv) in 1750 to 394 ppmv in 2012 and is currently increasing at the rate of 1.9 ppmv year-1 (NOAA, 2012). Atmospheric CH₄ concentration has increased from about 715 to 1826 parts per billion by volume (ppbv) in 2012 over the same period and is increasing at the rate of 7 ppbv year-1 (IPCC, 2007; EPA, 2013). Similarly, the atmospheric concentration of N₂O has increased from about 270 ppbv in 1750 to 325 ppbv and is increasing at the rate of 0.8 ppbv year-1 (IPCC, 2007; EPA, 2013).

The UN designation of 2013 as the International Year of Water Cooperation aptly demonstrates growing gap between water supply and demand. These symptoms, which are already visible in a few regions around India, are soon to assume a national proportion and may become permanent feature of the water sector in the country, unless suitable policies are adopted quickly to manage water demand and supply at different levels. Water demand is growing fast due to a rapid population growth and economic activity, but water supply is not growing at the same rate because of serious ûnancial and physical limits for supply augmentation. Water resources developed at present amount to about 680 km³, which constitutes 61% of the utilizable potential of 1122 km³. However, it is difficult to add supply beyond this level due to heavy costs, environmental concerns and interstate water conûicts. In contrast, the total demand for water is projected to reach 784–843 km3 by 2025 and 973–1180 km³ by 2050 (Ministry of Water Resources, 2000). Recent research studies predict that, if the demand– supply gap continues to increase, nine basins that have over four-ûfths of the total water use in India will face physical water scarcity by 2050 (see Amarasinghe et al., 2007). For a heavily populated, monsoon-dependent and rural-based country, such as India, water scarcity of this magnitude will not only lead to serious water conûicts among sectors and regions, but also have a devastating effect on the food and livelihood fronts.

Mammals are homeothermic, meaning that they have the ability to control their body temperature within a narrow range in an environment whose temperature may change over a wide range.

India is experiencing a phenomenal spurt in the growth of livestock and poultry sectors through various timely and quality measures scientifically over a few decades. Milk production rose by a large leap from about 17.0 million tones in 1950 to about nearly 100 million tones in 2005 standing first in the world for maximum quantum of milk production. From about a ‘naught’ during 1950, the commercial layers have increased to 220 millions in 2005 producing 4500 crores of eggs every yearranking 5th in the world. The meat production is absolutely fascinating with 20 million birds in 1960 to about 2100 million in 2005 (Table 10.1).

Introduction

The Indo-Gangetic plain (IGP) is of great importance for the food security of India. It extends over 1,600 km with a width of 320 km, including the arid and semi arid environments in Rajasthan and Punjab and the humid and per humid deltaic plains in west Bengal (Shankaranarayana, 1982). During the green revolution period in the early 1960s, production increased through area expansion and intensification of the rice –wheat system. Driving forces included suitable thermal regimes for rice and wheat cultivation, development of short- duration, nitrogen responsive cultivars, expansion of irrigation and an ever increasing demand for food from the rising population. The rice –wheat system, covering an area of around 10 million hectares (mha), is the major cropping system in the IGP. These two crops together contribute more than 70 % of total cereals production in India from an area of around 25 mha under wheat and about 40 mha under rice. The small states of Punjab and Haryana contribute 20 % of the total national grain production and 50 % and 85 % of the government procurement of rice and wheat, respectively (Singh, 2000).

Introduction

It is estimated that about 16 per cent of total geographical area of India (329 m ha) has moisture index value below - 66.6% and is thus classified arid. This area is further classified into hot arid (36.8 m ha) and cold arid (15.2 m ha) regions (Ramakrishna et al., 2000). The hot arid region is characterized by extreme temperatures, low (<500 mm) and erratic rainfall, very high wind velocities, low humidity, high PET (>1800 mm) and frequent severe droughts which occur once in three years to alternate years in general. The soil moisture and soil temperature regimes are aridic and hyperthermic, respectively. The hot arid region exists in Rajasthan, Gujarat, Andhra Pradesh, Punjab, Haryana, Maharashtra, and Karnataka (Fig 1).

Introduction  

Developing effective strategies for improving and stabilizing rainfed crop production continues to be a prime concern in the semi-arid region of western India. Rain water management is most crucial aspect in rainfed production systems. Growing uncertainties associated with rainfall pattern (Ali et al., 2007) add to the complexity of the challenge. The medium deep black soil region of Rajasthan is spread predominantly in Jhalawar, Kota, Baran, Bundi, and Sawai Madhopur districts of South-eastern Rajasthan (Fig. 1). This region is characterized by almost flat alluvial plains interspersed with hills of Arawali and Vindhyan ranges and rock outcrops. 

Introduction

Soil is considered one of the world’s limited, non-renewable resources. Under cropland conditions, it takes between 200 and 1000 years for 2.5cm of topsoil to form (Piementel et al., 1995). The continued maintenance of fertile soil is essential in order to meet basic human needs. It strengthens the provision of ecosystem services such as food production and climate regulation, and provides the basis of livelihoods for millions of people across the world (Ma, 2005). The multi-functionality of soils is key to the sustainable use of land and soils. A healthy soil performs six essential functions (Andrews et al., 2004) namely: i) Physical Stability and Support, ii) Water Relations, iii) Resistance and resilience- iv) Nutrient Cycling, v) Biodiversity and Habitat and vi) Filtering and Buffering. These soil functions are controlled by various soil properties. Among them soil structure is one of the most important properties of soil, which describes soil condition and has a great influence on crop production.

Introduction

Climate change has undoubtedly resulted in greater public and scientific involvement. Climate change refers to any change in climate over time, whether due to natural variability or as a result of human activity (IPCC, 2007). The United Nations Framework Convention on Climate Change (UNFCC) defined it as a change of climate that is attributed directly or indirectly to human activity which alters the composition of the global atmosphere and that is in addition to natural climate variability observed over comparable time periods. World Meteorology Organisation defines climate change as statistically significant variation in either the mean state of the climate or in its variability, persisting for an extended period (typically decades or longer). 

Introduction

Modern agriculture has been of great help in alleviating hunger from the world, because the world population more than doubled itself during the last half of the 20th century; it increased from 2.5 billion in AD 1950 to 7.1 billion in 2012 (USCB, 2013). It is predicted that the world population will again double itself by the end of the 21st century and will touch the 12 billion mark. Most of this increase in population has been, and will be, in the developing countries in Asia, Africa and South America. India occupies 2.4 percent of the total land area of the world, but supports 16.7 per cent of the world population. Like many other developing countries in the world, population in India is increased from 345 million in 1947 to 1210 million as per the 2011 census with a growth rate of 1.76 during last decade. Therefore, pressure on land has been mounting up at an alarming rate. Population growth coupled with live stock population expansion, urbanization and industrialization are major contributory factors to it. The unscientific and unplanned exploitation of this limited resource takes its toll in terms of degrading the land. A large proportion of the land area shows clear evidence of advanced and continuing degradation seriously affecting the country’s productive resource base (Abrol and Sehgal, 1994). Jammu & Kashmir and  Nagaland  have maximum share of their land (94%) under degradation. This is primarily due to large areas under mountains, cold deserts and other such degraded lands. In the agriculturally prominent states like Uttar Pradesh (63%), Madhya Pradesh (50%) and Karnataka (46%) (Shalander Kumar, 2011) the extent of land degradation is of great concern and posing a big threat to the natural resources, resulting in almost 5 billion tonnes soil and 6 million tones of nutrient loss every year (Singh, 2009).

2.1. The Physical environment
    Light
    Soil temperature
    Water dynamics

2.2. Chemical environment
    Production of phytotoxins

2.3. Biological environment
    Trophic dynamics
    Community structure
    Biodiversity

Abstract

Indigenous water saving technologies in arid and semi-arid environment is a local traditional practice for effective use of the limited water supply. These technologies can be used as a base for future development that can be made on these technologies through incorporating the current industry tools. The importance of studying the indigenous knowledge and practices is that it can help to develop enhanced versions of these technologies, and to understand the ability of local communities to adopt the newly developed technology. In Sudan, several indigenous water saving approaches has been used by local societies at various scales. An insight for these technologies, their strength and weaknesses are given here. On “Haffir” (water ponds), Wadi control, and water diversion methods were used for a long time of history for water collection and conservation. At farm scale, terraces, mulching, intercropping, low tillage, fallow, low-water consumption crops and fast maturing crops are common indigenous water saving technologies. Traditional water storage in trees such as Baobab and water-melon is an indigenous proactive along the history in western Sudan to store rain water for long dry season.

Why Water Budget?

The reliability of water supply in desert regions is at risk due to a multitude of issues including low rainfall, low snow runoff, court-ordered water transfer restrictions and hence higher price of wholesale water. Agencies in desert regions understand the importance of improving water supply reliability, facilitating better water storage, adapting to changing climate patterns and reduced precipitation, improving Environment and Water Quality.

The Desert regions have always fought back the perpetual water scarcity with infrastructure designed around saving water and utilizing alternative water resources. Off late, not only new construction but also new policies and programs have added to their water conservation activities.

One such program attends to the fair distribution of water by tending to consumers who are price sensitive and hence use water without wasting it and by extra-charging those who do not know where to put a stop to their wasteful water use.

Abstract

The UAE Space Reconnaissance Center (SRC) is accounted as a major national and regional source of up-to-date geospatial data, with direct reception of IKONOS, IRS and KOMPSAT satellite imagery as well as access to some other satellite and aerial imagery resources; an activity which covers the whole Middle East region. The main concern in monitoring the environment of UAE and surrounding countries is the desertification process, the monitoring of which requires careful watching of the sand movement and some other relevant features.

This paper throws light on the role of various types of satellite images in monitoring desertification, by utilization of IKONOS, IRS Pan and Landsat TM images covering part of Liwa and Alain areas, representing the two main dune regimes; Liwa and Manadir, which constitutes the northeastern edge of the Empty Quarter sand sea.

The availability of high resolution images makes it possible to detect the yearly or even seasonal sand movements, being controlled by the prevailing wind conditions and distance from the main sand source. The results clarify that movements of up to 25m was encountered at some small sand dunes and about 10m for larger sand dunes, towards the SSE and SSW in Liwa area. In Rimah area a movement of up to 30m was noticed at a small sand dune towards the ENE and about 12m shift in the hinge of a larger sand dune towards the NW. Temporary or permanent ? movement of thin sand sheets can reach 100’s of meters, was easily detected on Landsat images; ~ 25km NE of Alain city. The 5m panchromatic images, on the other hand, helped in tracing sand movements measured in few 10’s of meters, and interpretability of such images was enhanced by merging them with Landsat imagery.

INTRODUCTION

The discipline of Agrometeorology, an applied science is less than fifty years old. Its services are operationally used by individual farmers in developed countries, and by agricultural or development services in more than half of the countries of the world. Its contribution to agricultural production by examining forecast is sought in virtually all countries. In many countries, the respective governments have expressed the desire to use meteorological information to a much larger extent in day-to-day farm planning and operations. The climate database is used for the development of practical criteria in planning and management of irrigated and rainfed crop production system (Martin Smith, 2000).

Though a huge set of Agromet data exists in India, its utility has not been effective due to the scattered location of these data sources and the impediments for free flow of data to the users to analyze and interpret for real-time decision making in agriculture. There is also a considerable time lag between the actual observation and data availability. In view of the importance and the immediate exigency to centralize the database system for helping the researchers and planners, a central agrometeorological databank facility funded by DST from 1998 to 2003 and later by ICAR with the following objectives was established at Central Research Institute for Dryland Agriculture (ICAR), Hyderabad.

INTRODUCTION

Rubber cultivation in regions extending from 10°N to 10°S latitude is known as the traditional region and the areas other than its natural climatic origin is termed as the non-traditional region. Northeast India comprises majority of the non-traditional areas in India with major climatic constraints like high seasonal rainfall, excessive precipitation and to some extent dry conditions. These areas extending from 22 to 29^°N latitude, holds promise in extending rubber cultivation because of its exceptional climatic make-up and abundant amount of annual precipitation (2000 mm) distributed over a fair period of time.

This perennial crop generally yields latex rubber at the 7th year after planting (with an economic life span of 20 years), although the period (immaturity period) it requires, is higher in the non-traditional region (Rubber Growers Companion, 2006). This immaturity period has also been shown to reduce with water availability in sub-humid climates (Vijayakumar et al. , 1998). Harvest of this crop is by tapping. Tapping is a process of controlled wounding during which thin shavings of bark are removed, thus opening the latex vessels which exude latex. Dry rubber yield is obtained after the latex is coagulated and rolled into sheets (about 500gm) which is then smoked and dried.

This chapter reviews the published information on tsunami and attempts to characterize tsunamigenic sediments in terms of their microfossil content. Tsunamisare long-period waves generated by vertical displacements of marine watercolumn due to earthquakes, volcanic explosion and landslides. These waves can exceed heights of 25 meters (in shallow water) and lengths upto 100km with a velocity of more than 1000km/hour. Even at this magnitude, they are undetectable in deeper waters owing to very low wave height which in turn reduces significantly the response time, causing sudden havoc along coasts. They can cause flooding of coastal areas and affect areas thousands of kilometers away from their point of origin. These characteristics of tsunami imprint ensuing sediments with unique assemblage of microfossils.

INTRODUCTION

Shallow water progressive waves with very large wavelength and long duration caused by the rapid displacement of ocean water are called “tsunami”. Tsunami is a sudden non-meteorologically induced impulse in water regardless of size. Tsunamis are formed by submarine tectonic activity more often due to earthquakes and less frequently due to volcanic eruption, landslides near the coast, meteor impact and nuclear explosions.

The velocity of the tsunami varies and depends on many parameters such as bathymetry, height of the originating wave, initial pressure changes in the sea, etc. and can travel at a speed of more than 1000 km/hr. At the place of origin (directly above the epicentre of submarine earthquake or any other causative factor), the wavelength may be upto few tens to several hundred kilometres but the wave height is often less than one metre only. Since the velocity is proportional to the depth of the water column, it gets reduced to few tens of kilometres as the tsunami approaches the coast. However, the wave height increases significantly reaching 100 m in extreme cases. As a result, the tsunami strikes the coast with massive force. The effect is colossal in islands with low relief. The tsunami waves appear as flooding with water rushing inside the land more violently and with great force towards a river course. In several cases, when the tsunami arrives, the water level in the sea may drop significantly and the waters receding several hundred metres come back with great speed drubbing the coastal lands doubly from both the directions. Though an event of short duration in terms of geological history, tsunami deposits, owing to their higher rate of deposition and other salient characteristics, find place in stratigraphic records. This chapter is an attempt to review the characteristics of tsunami and tsunamigenic sediments, to find out the ability of microfossil content of such sediments for characterization and to identify tsunami deposits in stratigraphic records.

Need for systematic mapping and hazard zonation is emphasized in this chapter. Though prevention of natural disaster is not possible, its destruction could be minimized through implementation of effective hazard management system. With this motive, the coastal region between Tangapatnam and Ovari, Tamilnadu State has been classified into various categories of vulnerability based on its response to the 26th December 2004 tsunami. Based on the extent of seawater inundation and coastal geomorphic features, we have assessed the tsunami impact and estimated the behavior of the beaches in case of similar havoc in future. This study had shown that the maximum seawater inundation recorded in the study area is 750m in Colachel and the minimum is 100m in Kadiapatanam, Mandakadu and Vaniakudy areas. Chinnamuttom, Kanyakumari, Manakudy, Pallam and Colachel areas are under high risk.

INTRODUCTION

On 26^th December 2004, tectonic disturbances happened near Sumatra Island with an intensity of 9.3 in the Richter scale wrecked havoc on southwest part of India. In addition to inflicting life and infrastructure loss, the resultant tsunami event had also eroded severely the coastal region and modified topography of beach and shallow coastal regions. It did raise the concern of scientists and emergency planners about the impact of larger earthquake and consequent tsunami should there be any recurrence of such event. Despite becoming aware of tsunami hazard, there has been confusion about areas at risk and areas of safety. This chapter is an attempt to assess the vulnerability of part of Tamilnadu coast based on its geomorphological conditions and the impact of recent tsunami. The hazard maps have been generated and are intended for educational purposes, to improve awareness of tsunami hazards and to encourage responsible emergency planning efforts by illustrating the range of possible tsunami events.

This chapter is an attempt to introduce basic facts about earthquake generation and the role of earthquakes in triggering secondary geohazards. Earthquake, unlike manyother geohazards is yet to be fully understood towards occurrence and magnitude for better mitigation measures. Though unpredictibility of this hazard makes it dangerous, earthquakes seldom kill lives. Instead, poor ability of man-made structures against ground-shaking waves has been the real cause of life loss and damage to property in most of the earthquake incidences. Furthermore, earthquakes generate secondary geohazards such as landslide, failure of dams and reservoirs, etc. Thus, earthquake, as a natural hazard has its own characteristic way of potential impactand hence classifying vulnerability of different regions and creating awareness on potential impact among common public is essential.

INTRODUCTION

The term “earthquake” denotes “shaking/vibration/trembling/ quivering/shuddering/ wobbling of Earth”. Earthquake is the quickest and most unpredictable natural hazard. It is nothing but a series of suddenly generated elastic waves occurring in the Earth due to internal and/or external causes from shallow (few kilometers) to about 700 kilometers depth. It is a form of motion of wave energy transmitted through the surface layer (crust) of the Earth. One generalization that can be made out of scientific and mainstream media information about earthquakes is that, “earthquakes seldom kill; but the associated phenomena such as landslides, flooding, volcanic eruptions and collapse of natural and man-made structures cause the real damage to lives and property”. This chapter is an attempt to describe the basic elements of earthquakes and few mitigation measures.

Readers are introduced through this chapter to a geohazard (Landslide) that is most frequently publicized in mainstream media. Systematic examination of landslides and associated structural, tectonic, geological, geomorphological, meteorological, hydrogeological characteristics and land use pattern of Nilgiri hill area had indicated that steep slope, dipping of rockstowards slope, presence of clay layering in weathered rock types, events of continuous heavy rains, flooding on the slopes and improper land use practices play a major role in the genesis of landslides. Inaddition, ongoing seismotectonic activities in Southern Granulite Terrain of South India and reactivation of hidden blind shear zones were identified to be causative factors of recent increase of landslide occurrences.

INTRODUCTION

The downward movement of consolidated and unconsolidated soils and rock en masse from any geomorphic feature due to natural or manmade causes under the influence of gravity is termed as landslide (GSI, 1982). Nevertheless, presence of water, clay material, weak joints, favorable slope and many other characteristics also act as catalysis for this event. Landslides are one of the common geological hazards that affect countless population in India, especially in hilly terrains. Different reasons have been ascribed to different landslides of various terrains. Among them, reactivation of Bhavani shear zone (Prasannakumar and Llyod, 2007), high anthropo-geomorphic intervention (Basu, 2005), local geology, precipitation and slope (Bhattacharjee, 2005), presence of local vertical faults, triangular facets, abrupt deflection of streams and neotectonism

This chapter portrays flooding as a geohazard that can be managed with ease through simple and effective measures. Flooding is a recurrent geohazard that affects vast lands in India and elsewhere. Unlike many other geohazards, flooding event and probable area to be affected could be predicted with fairly accurate levels and hence, proper safety measures could be taken easily. However, as flash floods could not be predicted and the nature of flooding hazard that it brings in added danger of health hazard, crop damage and cutting off of supply and communication networks, flooding is as serious threat as any other geohazard. Scientifically designed urbanization and flood control measures are suggested for minimizing the potential impacts of flooding.

INTRODUCTION

Flooding is defined as a temporary submergence of a large area (that normally remains dry) under water by overflowing rivers and reservoirs as a result of heavy rains, high winds, cyclones, storm surges, tsunami, melting of snow or dam burst (Arya et al. 2005). The term “temporary submergence” denotes a time period ranging from few hours to about few months depending on type and location of flooding. Although flooding is a natural phenomenon that plays a major role in replenishing wetlands, recharging groundwater and supports agriculture, extreme demands on natural resources due to population growth, people and their property move closer to water bodies

Abstract

Geomorphology not only provides the panorama on the external architecture of the Earth surface, but also it is the record of the past geological events including the climate, especially of the Quaternary period. Detailed geomorphology map was prepared using the IRS LISS IV FCC and SRTM data showing the tectonic, denudational and fluvial landforms of Kollai hill, Eastern Ghats, Tamil Nadu. The geomorphic features showed that the Kollai hill can be divided into two as northern and southern blocks separated by a NE-SW active sinistral fault in the overall N-S rectangular hill. The integration all the geological , structural and geomorphic features show that the Kolli hill is under the grip of uplift in the south west with hinge towards north easterly. Because of this, the northern block/rim of the hill is fragmented into a series of East-West trending fracture/ fault swarms which are sympathetic tectonic grains to the Attur graben rimming the Kollai hill to its north. This phenomenon seems to control the overall resources and environment of the hill.

Introduction

The mountains are not only the store houses of natural resources like minerals, water, geothermal springs, forest & biomass etc., but also possesses unique & self-styled ecosystems drafting the mankind from the plains for comfort and livelihood. Further, the tourists are highly attracted by the mountain regions due to the ecosystems, climate and scenic beauty. Due to all these, the resources of the mountains are exponentially exploited during the recent 6–7 decades thus causing phenomenal depletion of natural resources and initiation of chains of environmental disorders, viz., deforestation triggered soil erosion, landslides, debris dumping along the slopes and foot hills, sedimentation of the downhill reservoirs & drainages, all of which in turn induce haphazard flooding. Hence, the Union and various Federal Governments have started working on the restoration of the ecosystems of their respective mountain regions in several nations. In the Indian sub- continent too, both under the Centrally sponsored schemes and the State funding, number of Hill Area Development Programmes have been initiated and going on especially in Himalayas, Easternghats and Westernghats. The state of Tamil Nadu possesses both Easternghats and Westernghats. While the Westernghats are found along the western part of the state with NNW-SSE orientation, the Easternghats represented by the Kollai- Pachhamalai hills, Shevroy - Chitteri – Kalrayan hills and Javadi hills, aligned in N-S direction, are traversing the Central part of Tamil Nadu. To comprehensively understand the resources, hazards potential, the ecosystems and also the modern geological processes which only control and tutor them, a geomatics based study was carried out in Kollai hills so that it can be used as a reference study to all those who are engaged in eco-restoration and hill area development programmes in India.

Abstract

The Himalayas of Himachal Pradesh is prone to landslides due to inherent geodynamic conditions, rainfall and anthropogeny. Besides multi-variate studies on the landslides of Himachal Pradesh, instrument based early warning system was attempted by taking Jhakri landslides as the test site. Various instruments viz; piezometer, vertical inclinometer, Rain gauge, etc. were installed and the paper discusses about the methodology adopted in the installation of the instruments and the observations made from the instruments. While Piezometer did not reveal much information, the Tiltmeter showed minor movements.

Abstract

The landslide is a disaster which causes rampant loss to life, property and ecosystems. With increased awareness and technological development, the number of monitoring stations near hazardous regions have increased. To give warning prior to the occurrence of a landslide, the soil/rock mechanics of the underlying bed needs to be studied and understood. This paper examines the current literature and elucidates some features of state-of- the-art landslide monitoring systems.

Keywords: Field based sensors, Wireless sensor network, Landslide monitoring

INTRODUCTION

Advancements in technology have helped us to understand nature better than before, yet the geotechnical parameters causing landslides could not be quantified accurately. The efforts taken in predicting landslides are clearly moving towards this objective and this can be seen by the number of monitoring stations that have been setup in landslide prone areas around the world. The data that is obtained at each location is important in understanding landslides. Each location is unique in terms of soil properties, groundwater, inclination of the slope and weather conditions and consequently, each deployment is unique.

The paper narrates the instrumentation based forewarning systems functioning around the world. The paper discusses these aspects hierarchically viz; Landslide prone areas in India, geotechnical instrumentations and their merits, influence of rainfall on landslides, correlation between rainfall and pore pressure, the relevance of different systems for different scenarios etc.

Abstract

The landslide vulnerability of the state of Mizoram is already high due to lithology, structure, geomorphology and seismotectonics and also the rainfall, like the other states of the northeastern region of India. The extensive mining activities along the highways for the building and road materials appear to cause additional problems of landslides. So two prominent landslides occurring in Keifang and Tlungvel quarries,Mizoram were studied. Besides taking stock of the geosystems, boreholes were drilled in both slides and from the total depth drilled and the modified core recovery, the RQD were worked out for the rocks which indicates that geotechnically the rocks of Keifang quarry are weak when compared to Tlungvel quarry. The geophysical surveys too lead to similar inferences. On the basis of the studies a set of mitigation strategies have been suggested.

ABSTRACT

Mineral exploration is not only highly imaginative and creative but a very costly activity as well. The fast emerging Geomatics technology is a real boon in mineral exploration as it encompasses a whole spectrum of solutions and services which are of great help for exploration geologists. Geological maps which generally form the basic requirement for any kind of natural resources inventory operations currently witness tremendous changes and the same is mainly attributed to the integration of Geomatics technology. Usage of Geomatics has revolutionized the art of mineral exploration as geological maps can be easily integrated with other important details like geomorphology, structure and tectonic pattern, geophysical data etc. This kind of data integration facilitates for the better identification of mineralized zones. In addition, GIS with its powerful analyzing capability provides tools at several stages in the process of mapping for building up a database containing various types of data for quantifying and extracting features related to mineralization. The present paper narrates an overview of mineral exploration using Geomatics technology.

ABSTRACT

We report here the occurrence of chrysoberyl bearing gem pegmatitesof Southern India. The Pan-African Chrysoberyl mineralization is associated with intrusive event of grey pegmatites within granulite facies parametamorphic aluminous khondalites. Lithological and structural controls of chrysoberyl mineralization are discussed. The chrysoberyl occurrences in southern India, southern Madagascar and Sri Lanka provide strong evidence for India-Sri Lanka-Madagascar juxtaposition in the East Gondwana assembly with the Achankovil Shear Zone of Southern India one side extending into Ranotsara Shear Zone in Southern Madagascar and other side into southern tip of Sri Lanka.

ABSTRACT

Lineaments are the surficial expression of sub-surface phenomena which are well discerned from low-orbital data, satellite data with its synoptic view and repetitive coverage and help to bring out more information on structural features hither to unknown by conventional geological surveys. Their study paved way to many new concepts on tectonism, mineralization, structural deformity etc. of an area both in regional and local perspective. In the present study, a small area was selected after careful observation, for their importance in mineral deposits. The lineaments are mostly structurally controlled and analysed for their relationship with the base metal deposits of the area. Moreover satellite parameters like spatial resolution, scale etc., and are observed for their changes in their orientation and relationship with the deposit of the study area, Jambughoda of Panchmahal District, Gujarat Satellite data of Landsat MSS and TM are used for the analysis. The results proved that the satellite parameters are important criteria and play a vital role in lineament analysis for mineral investigation.

ABSTRACT

Assessment of groundwater potential has wide importance in the exploration, management and development of groundwater resource. The fact that geologic and topographic factors, such as, geomorphology, lithology, structure, soil and slope control the occurrence and movement of groundwater in a region has been made use of in satellite remote sensing to aid groundwater exploration. In hard rock terrains, due to lack of primary porosity, lineaments have greater importance as those can be zones of secondary porosity trapping groundwater in its pore spaces.

In the present study, an attempt has been made to delineate groundwater potential zones in the hard rock terrain in the Gayatri River basin in Kerala, India, using satellite data. The study area which lies between 10o 26’N and 10o 45’N latitudes and 76o 21’E and 76o 54’E longitudes covering an area of about 1000 square kilometers is a drought-prone area. Landsat 7 ETM image of Gayatri River basin has been interpreted visually in a digital environment using ERDAS Imagine software to create geomorphology and lineament maps. Further, with the help of ancillary data, various thematic layers like, lithology, soil, drainage density, etc. have been created and subsequently updated using information obtained from the satellite data. Slope map of the basin has been created using Shuttle Radar Topographic Mission (SRTM) data. Integration of the thematic layers has been done in Arc/Info GRID GIS environment by giving weights to various thematic layers according to their importance in terms of groundwater occurrence. Finally, groundwater potential map of the basin has been prepared by classifying groundwater potential zones as good, moderate and poor.

ABSTRACT

With the increasing use of ground water for various activities, the fast decline in groundwater takes place. In order to prevent the aquifers from fast depletion, the ground water recharge is necessary. This study attempts to identify the favourable areas for groundwater recharge and suggest suitable recharge structures toaugment the aquifer system of the study area using Remote Sensing and GIS. The various thematic maps such as Geomorphology, Geology and lineaments, Soil, Slope, Land use, Drainage, Runoff, Depth to weathered zone, Groundwater level fluctuation and Water quality are used in the analysis. The favourable areas for groundwater recharge have been categorized into highly favourable, moderately favourable, less favourable and poor. To delineate areas favourable for recharge zone various themes are interpreted. The identification of ground water recharge zones for the study area is useful for improvement of water quality, quantity and better augmentation & management of Groundwater recharge.

ABSTRACT

The estimation of the water requirement of crop is one of the basic needs for crop planning on the farm and for the planning of any irrigation project. Water requirements of crops include the losses due to Evapotranspiration (ET) plus the losses during the application of irrigation water (unavailable losses) and the quantity of water required for special operations such as transplanting and leaching of excess salts for crop growth. It is therefore necessary to estimate the ET and Crop Water Requirement (CWR) for the efficient use of water and increased crop production. In the present study, meteorological data were collected and the crop ET (ETc) and the CWR were estimated using FAO Penmann – Monteith method for the cropping pattern of the Buthangudy canal command area situated at a distance of 2Km from the popular village Sethiathope, Cuddalore district, of Tamil Nadu, India, which is located in between the Kumbhakonam – Chennai NH – 45 main road. The methodology combines the capability of GIS and CWR to produce maps showing spatial distribution of water resources over large areas.

ABSTRACT

The use of Geographic information system to locate groundwater possible zone in Valapadi taluk of Salem was carried out using remote sensing and geophysical studies. The remote sensing methods involved in the visual interpretation of the satellite images for hydrogeomorphological and hydro structures favourable for groundwater. The geophysical method involved vertical electrical soundings to predict the sub-surface variation and to locate the water domain. Three geoelectric layers were delineated from the interpretation of vertical electrical sounding data and the map of the above results predict the depth extent of groundwater zone. The spatial distribution of the above results was identified through GIS.

ABSTRACT

Granite in the present day context is popularly known as the principal raw material in construction industry and also known for its value addition product as Dimension Stone in the global market. India is in pride possession of much sought granite varieties of the world. No doubt the demand for such granite varieties is quite high both for local and export markets but in reality the failure rate of granite quarries is also high, The technical reasons attributed for such failures being lack of application of proper scientific skill both in selection and mining ofgranite deposits. The past experience in the fieldof granite exploitation has thought us a lesson for application of geological knowledge in selection of right deposits and in adopting the right techniques. The selection criteria for construction purpose and for export market though looks simple, is more complicated in the case of dimension stone granite deposits, the reasons being the requirement of thorough knowledge in petrography,structure,geotechnical characters of the deposit. Considering the importance of the scientific knowledge, the present paper focuses on the various parameters for valuation of granite deposits. In other words, it emphasizes on arriving at a logical conclusion by applying the scientific knowledge in successful exploitation of the much valued granite deposits.

Abstract

An unprecedented tsunami hit the Andaman and Nicobar Islands and the coasts of Andhra Pradesh, Tamil Nadu, Pondicherry and Kerala on the 26^th of December 2004. The loss of life and property, though wide spread in all these areas, was very severe in thickly populated low lying coasts, such as Nagapattinam in Tamil Nadu. Survey of India, in association with the Department of Science and Technology, Govt. of India, New Delhi has taken-up the task of carrying out post-tsunami Mapping of the entire east coast of Tamil Nadu using Digital aerial stereo images acquired immediately after the tsunami. The project aims to generate ortho-rectified photographs on 1: 8000 scale, which are to be used for preparing damage assessment maps of the affected coastal areas. This paper discusses various issues related to Control Surveying, Digital Photogrammetry and Large Scale feature extraction that are involved in the mapping process in general and its credibility for tsunami damage assessment in particular.

Keywords: Tsunami, Digital Photogrammetry, Tsunami damage assessment in India.

Abstract

A large tsunami triggered due to a massive earthquake of 9.3M in the offshore of Sumatra on 26^th December 2004 created havoc in several countries of the Indian Ocean. The deadly tsunami waves lashed the towns adjoining the coastline of several countries including Indonesia, Thailand, Malaysia, India and Sri Lanka causing more than 1,50,000 deaths. The earthquake occurred along the plate boundary is marked by a subduction zone between the Indian plate and the Burmese micro plate. In Andhra Pradesh, six coastal Districts were affected and amongst them four south coastal districts experienced maximum damage. In the present study, Tuppalapalem (vagarru revenue village) of Vakadu mandal, Nellore District was selected as a case study for discussion in the article. The objective of the study was to make an inventory of the damages to the natural and physical resources, by preparing pre and post-tsunami maps on geomorphology, land use / land cover, tsunami inundation and finally the tsunami risk zonation map on 1:8,000 scale. In this process, water and soil samples of the affected regions were also collected and chemical analysis was carried out. The data on damages were collected using a specially formulated data sheet. High resolution IKONOS data of January 2000 and IRS data of January 2005 were used for the generation of respectively the pre and post-tsunami geomorphology and land use / land cover maps. Ground truth data were also incorporated in these thematic maps.

The study has revealed that the water in all the bore wells became brackish after tsunami. About 80 country boats, 40 fibre boats and nets were lost with an estimated loss of about one crore. The tidal waters damaged the bunds of the aqua-farms and deposited the transported sediments in them. The extensive casuarina plantations, were reduced by the onslaught of tsunami and the casuarina trees became brown due to their contact with tidal waters. From amongst the various geomorphic units mapped in the study area, the beach, spits, shoals, creeks, swales, palaeo creeks were inundated by tsunami where as beach ridges, dune complexes and stabilized sand dunes were not affected and hence inferred as barriers. Geomorphology, land use / land cover and the tsunami inundation maps, tsunami risk zonation map were prepared showing very high, high and moderate zones of tsunami risks. It is recommended to take up casuarina plantations extensively along the coast as a biowall, which will also provide employment to the local people. The shallow aquifers of the coastal environment were contaminated by the tidal waves. Hence, drinking water should be supplied through protected water supply schemes. As a part of the community development, proper awareness must be created through training and appraisal to the fisherman community to face such natural disasters. The coastal regulation zone act, which prohibits any construction activity within 500m of the high tide line, should be strictly enforced. Keeping in view of the experience, a holistic tsunami protection plan is needed to safe guard the Indian coasts.

The gaseous envelope surrounding the earth is called atmosphere. Thus, atmosphere can be defined as the dynamic layer surrounding the earth above its surface containing various gases, moisture, aerosols, etc. The atmosphere is retained by earth’s gravity.

The atmosphere protects life on earth by absorbing ultraviolet solar radiation, warming the earth’s surface through heat retention and reducing temperature extremes between day and night. The common name given to the atmospheric gases used in breathing and photosynthesis is air. The atmosphere has a mass of about 5.15 × 10¹⁸ kg, three quarters of which is within about 11 km from the surface. The atmosphere becomes thinner and thinner with increasing altitude, with no definite boundary between the atmosphere and outer space. The imaginary ‘Karman line’ lies at an altitude of 100 km above the mean sea level, and commonly represents the boundary between the earth’s atmosphere and outer space. The study of earth’s atmosphere and its processes is called atmospheric science or ‘aerology’. The atmosphere serves the life-system on the earth by the following activities.

A big layer of air called the atmosphere surrounds the earth. The air within this layer moves from place to place when it warms up or cools down. This moving air is known as wind. In other words, air in motion is called wind. Winds move moisture and heat around the world and also produce much of our weather.

The strength of the wind can vary enormously. Sometimes air moves slowly and the wind is barely noticeable. When the weather is clear there may be a gentle breeze. When the wind is still very light, but it can be felt and there may be rustlings by leaves. At other times, the air can move very quickly and become a gale or hurricane, blowing down trees and damaging electric poles and buildings.

Winds are part of a global air circulation system that acts to balance temperature and pressure around the world. Different parts of the world receive different amounts of heat from the sun. This differential heating in turn results in differences in temperature and air pressure around the world, which drives the world’s winds.

As equatorial areas are heated most, the air above them warms and rises as it becomes lighter than the surrounding air, causing an area of low pressure. In cooler areas, the air sinks because it is heavier and results in an area of high pressure. Winds will blow as air is squashed out by the sinking cold air and drawn in under the rising warm air. Any difference in temperature like this will always cause a difference in air pressure, and therefore winds will blow. These movements result in a global wind pattern, with air moving between different areas around the world and also at different heights in the atmosphere. Colder air from the poles tends to sink and move towards the equator closer to the surface of the earth. In contrast, warm air from the equator rises and moves towards the poles high in the atmosphere because it is lighter.

16.1 Introduction

It is well known fact that planners as well as end user’s have to consider any resources as technology from economic point of view. Therefore, it is important to have techno – economic analysis of each energy source option. In the feasibility study of particular energy option, three tier judgement approaches is required, which include technical feasibility, economical viability and social acceptability. Hence in the rural energy planning programme one has to considered techno socio economic analysis of an individual energy option. Since in integrated rural energy planning, locally available energy resources are used, presuming that it is socially recognized. Hence in the IRPE project, the need and scope of techno economic analysis in terms of economic analysis of different technical feasible options, before between “economic” and “financial” analysis should be kept in mind. An economic analysis is needed to verify that a particular energy source will provide “net benefit” to society as a whole, before its final integration in the energy context, while a financial analysis integrated in the energy practices. In simple wards, a financial analysis is concerned with goods and services, money inflow and outflows and the transfer of payments. An economic analysis also considers the social benefits and costs of goods and services which are not traded in a market.

18.1. Determination of Available Micronutrient Cations (Zn, Cu, Fe and Mn) in Soil

The available micronutrient cations (Zn, Cu, Fe and Mn) can be estimated in a single extraction with diethylene triamine pentaacetic acid (DTPA) as proposed by Lindsay and Norvell (1978). DTPA has the excellent property to combine with free metal ions in the solution forming soluble complexes. The stability constants of metal-DTPA complexes make DTPA as a most suitable extractant for simultaneous complex formation with Zn, Cu, Fe and Mn. In calcareous soil DTPA extractant may result overestimation due to excess dissolution of CaCO_3, thus releases occluded micronutrient cations which are not plant available. To avoid this excessive dissolution of CaCO₃, DTPA is buffered at pH 7.3 using triethanol amine (TEA). At this pH major part (3/4^th) of TEA is present as HTEA⁺ (protonation) and exchanges for Ca and Mg ion from the soil exchange site. This increases concentration of Ca and Mg in the solution phase and suppresses dissolution of CaCO₃. The DTPA has the capacity to complex each of the micronutrient cations 10 times of its atomic weight and it ranges from 550 to 650 ppm depending on the micronutrient cation.

The amount of cation in the extract is determined on an atomic absorption spectrophotometer (AAS). The experimental condition such as shaking time, DTPA concentration, pH and temperature during shaking influence the amount of Zn, Cu, Fe and Mn extracted. Increase in shaking time and temperature markedly influence the extractability of these cations.

Introduction

R is one of the most popular platforms for data analysis and visualization currently available. It is free, open-source software, with versions for Windows, Mac OS X, and Linux operating systems. R is a language and environment for statistical computing and graphics, similar to the S language originally developed at Bell Labs. It’s an open source solution to data analysis that’s supported by a large and active worldwide research community. But there are many popular statistical and graphing packages available e.g. Microsoft Excel, SAS, IBM SPSS, Stata, and Minitab etc., however R has many interesting features so why it is mostly followed by researchers and academicians. Few of the major features of R are given below:

Introduction

Quantum Geographical Information System (QGIS) is an open source GIS environment. The software package is available freely in web https://www.qgis.org/en/site/forusers/download.html) and can be installed in a variety of computer platform e.g. Windows, Linux, Mac OS X, Android etc. Latest information on QGIS is available inhttp://www.qgis.org/en/site/. Basically, the QGIS GUI is divided into five areas: (i) Menu Bar, (ii) Tool Bar (iii) Map Legend, (iv) Map View and (v) Status Bar. QGIS allows users to define a global and project-wise coordinate reference system (CRS) for layers without a pre-defined CRS. It also allows the user to define custom coordinate reference systems and supports on-the-fly (OTF) projection of vector and raster layers. All of these features allow the user to display layers with different CRSs and have them overlay properly. QGIS has support for approximately 2,700 known CRSs. Definitions for each CRS are stored in a SQLite database that is installed with QGIS. The CRSs available in QGIS are based on those defined by the European Petroleum Search Group (EPSG) and the Institute Geographique National de France (IGNF) and are largely abstracted from the spatial reference tables used in Geospatial Data Abstraction Library (GDAL). For Post GIS layers, QGIS use the spatial reference identifier that was specified when the layer was created. For data supported by OGR, QGIS relies on the presence of a recognized means of specifying the CRS. In the following sections, few basic GIS analysis using example spatial data from arid western India is discussed. However, readers are advised to go through different tools and functions available in QGIS after installation of the system in personal computers.

Introduction

GIS (Geographical Information System) based mapping takes cogence of three major geometrical dimensions, point, line and polygons and in GIS these three features correlate their relationship through a concept called Topology. Among the various applications where covariate processing requires specific attention, the landuse/ land cover and Digital Elevation Models/surfaces or terrains are the major area of interest. Use and processing of data for these covariates carries importance as accuracy of both these aspects would influence the derivatives extracted out of them further. For example, if landuse is improperly defined, the site for which planning is proposed may not sustain, similarly, point data/elevation data in case of DEMs would decide the exact topography of any landforms for their further utilization. For their use in GIS, while DEMs depend upon point data, the landuse/ land cover will be taken care by polygons. For the purpose of the study, we are going to discuss about these two covariates in the following paragraphs.

Generally, Covariate (covariable) (koh-vair-iãt) in statistics is defined as a continuous variable that is not part of the main experimental manipulation but has an effect on the dependent variable. In other words, as per ANCOVA (Analysis of covariance) definition: a covariate is a control variable.

Introduction

In India, hot arid ecosystem covering an area of 31.7 million ha lies at north western part of the country and 62% of this area falls in western Rajasthan covering 12 districts i.e. Jodhpur, Jaisalmer, Jhunjhunu, Sikar, Hanumangarh, Sri Ganganagar, Bikaner, Barmer, Pali and Sirohi. The major landforms in arid western Rajasthan are dune and inter-dune plains having sandy to sandy-loam textured soils. Temperature remains high for most part of the year reaching up to 42-45°C during prolonged summer months (April to July), whereas annual rainfall is very low and highly sporadic (100-400 mm) mainly occurs during August and September. Annual potential evapotranspiration ranges from 1500-2000 mm. Loss of fertile top soil from denuded soil surface through wind erosion is frequent during summer months. The region is subjected to frequent occurrence of droughts, once in every three years, which further intensifies the process of desertification (Samra et al. 2006). Shorter growing period, sandy soils, very low available water capacity, inadequate nitrogen and phosphorus availability are the major constraints. Soils are prone to severe wind erosion, terrain deformation and nutrient depletion. The region is mostly mono cropped and double cropping is being practiced extensively in canal and tubes well command area. Extensive fallowing in the past even in very good rainfall years because of uneven undulating topography and severe windstorm are the cause of concern. Ground water is deep and is usually brackish, declining at alarming rate due to excessive withdrawal for irrigation and other purposes. The region, however, sustains on perennial vegetation of Prosopis cineraria, Tecomella undulata, arid shrubs and grasses, which are rich resources of fodder for animal because cropping is affected by vagaries of monsoon. During last two to three decades, a 2 to 3-fold increase in irrigated areas with cultivation of both kharif and rabi crops has been recorded and most of these increments are resulted through conversions from rainfed areas, grazing lands and sand dunes into irrigated areas.

Concept and Definition

Desertification is a major problem in the drylands of India, affecting the way of life for its inhabitants. The problem is more severe in the arid lands in the northwestern part of the country. There have been a few numbers of definitions of the word “Desertification”. However for simplicity of its origin and meaning we would refer to two of the frequently used ones; (1) proposed in 1991 by UNEP: “Land degradation in arid, semi-arid and dry sub-humid areas resulting mainly from adverse human impact and (2) prepared for the Earth Summit at Rio, held in June 1992, for inclusion in Agenda 21, as “Land degradation in arid, semi-arid and dry sub-humid areas resulting from climatic variations and human activities. (Anonymous 1992).

Comparing two of these initial definitions, it would show that first one indicated desertification as a state of natural resources like soil and vegetation, mainly resulting from human activity while the second one included climate as a major cause. However, it reduced the emphasis of human activities as being the primary responsible factor and tried to link the possible impact of climate change on desertification. But the simplicity of the 1992 definition of desertification helped researchers to bring in sharp focus on the special environmental and socio-economic problems of the drylands.

So over the years, the key words that explains the term “desertification” has been changing or are being amended for specific purposes. This would at least mean that the problem of desertification is still debated world-wide, and its impact is not limited to some nations/regions as was presumed and discussed in first of UNCCD platforms. Therefore, as a precaution and combating this process, few catchy words like non-sustainable management, productivity, over-exploitation of natural resources, dryland livelihood, droughts are found to surround the word desertification. Earlier, some, people equated desertification with advancing boundaries of the existing desert and in India, examples of expansion / contraction of geographical boundary of Thar desert was a public debate among various researchers and planners. In the same time, some of the definitions tried to broaden its geographical scope so that greater populations suffering from adverse effects of land degradation would benefit out of various remedial measures.