eChapters

ABSTRACT

The practice of agroforestry in the hills and mountains of Himachal Pradesh is as old as the hill agriculture itself. Farmers are retaining trees on the farmlands for the multiple benefits they provide. The selection of the trees, their planting pattern and density is chosen in such a way that it had minimum effect on the associated crop. The present paper gives the prevalent agroforestry systems with their components in different agroclimatic zones of Himachal Pradesh along with their management practices. Adoption of landuse practices depends to a large extent on status of the farmer concerned. Paper presents the association between type of farmer and the corresponding agroforestry systems they adopt. Sustainability of agroforestry systems, their role in climate change and social and economic gain of agroforestry systems in hills had also been detailed. A comprehensive list of agroforestry components had also been appended as annexures.

INTRODUCTION

Farmers throughout the Indian Himalayas covering about 16 states partially or fully have nurtured trees on their farms and in the agricultural landscape both for production and protection benefits for millennia. Mountainous region like Himachal Pradesh located in western Himalayan range present wide range of tree growing practices and systems owing to the diverse physiographic and demographic mosaic.

The state is located between 30° 22’ 40” to 33° 12’ 40” N latitude and 75°47’ 55” to 79°4’ 20” E longitude and extends over a geographical area of 55673 km² which is 1.69 per cent of the country’s area and 10.5 per cent of the Himalayan landmass. This land locked state is bordered by Jammu and Kashmir in the north, Punjab and Haryana in the south–west and Uttaranchal in the south–east. In the north–east the state forms the international boundary with the Tibet. Agricultural landscapes are characterized by undulating topography wherein terraced fields are made on medium to steep slopes. Crop fields on sloppy lands are in general 5-10 m wide and 20-30 m long almost conical on both ends and wide in the middle. In valley areas and on lands with gentle to mild slopes (up to 40%) large sloping fields have been developed manually by the farmers where Government has undertaken land consolidation.

ABSTRACT

The paper introduces the biophysical environment and landuse pattern of newly formed state. On the basis of ownership of land the scope of adopting agroforestry had been discussed. Existing agroforestry systems under different agroclimatic zones of Uttaranchal are provided with examples. Tree improvement program and system development research carried out under AICRP on Agroforestry for Terai zone of the state has also been discuused in the paper. Constraints in adopting and carrying out research in agroforestry along with future strategies to extend agroforestry in Uttaranchal are also given in the paper.

INTRODUCTION

Uttaranchal, formed on November 9, 2000, is the 27^th state in India. The state is spread over 53,483 km² of land, which extends between 77° 34’ and 81° 02’ E longitude and between 28° 43’ to 31° 27’ N latitude. It covers 1.67 per cent of the country’s total area and is home to 84.7 lakhs of people as per the provisional census report 2001. The entire state forms part of the Central Himalayas. The state is strategically located and forms part of the Northern boundary of the country sharing its borders with Nepal and China. The entire region, except the southern most foothills belt, is mountainous with a series of ridges and valleys. Starting with an altitude of about 240 m in the tarai on the southern fringes, the terrains rise to 7817 m in the north with in a short width span of about 160 km. It touches Tibet in the north, Himachal in the west and northwest, gangetic plains of Uttar Pradesh in the South and Nepal in the east. Uttaranchal has two administrative divisons, the western half known as Garhwal and the the eastern region known by the name of Kumaon.

ABSTRACT

Punjab is the richest state in the country in term of per capita income and has earned the name as food bowl of the country by putting 84-85 per cent of its geographical area under highly intensive, technical and mechanical agriculture with cropping intensity as high as 185 per cent and contributing more than one third of rice and half of its wheat production to the central pool of food reserve. The food grain production in the state has increased approximately twelve times in a span of about 50 years after independence from 20 lac tones in 1950-51 to 234.89 lakh tonnes in 2002-2003. Achieving this high productivity without caring for natural resources has resulted in a considerable loss in the inherent production potential and deterioration of soil health. As a result, man is getting serious warning signals in the form of lowering of water table, drought, high rate of environmental pollution, extremes of climatic parameters, etc. Agriculture in the state has become too intensive, wasteful and reckless and the radical changes are required to maintain the balance. Therefore, there is a strong thinking to diversify farming in the state to maintain the sustainability of the whole system. The state government is stressing hard to save the natural resources through the diversification in traditional crop rotation and adopt resource-conserving measures.

ABSTRACT

Haryana being predominantly agricultural state had only 2.86 per cent recorded forests at the time of its inception. Agroforestry has been an age old practice in Haryana as in other parts of India. It has existed in various forms through the time immemorial. Farm boundary plantation/natural regeneration and scattered trees in the farmlands were the main agroforestry interventions in Haryana till the seventies. To counter the environmental degradation and to provide fuel, fodder and timber different tree-crop combinations were tried for accessing their compatibility. As a result number of agroforestry systems had been recommended and are discussed in this paper. The paper also include methods of managing the perennial component of agroforestry system. Economics of some of the successful systems has also been discussed.

INTRODUCTION

Haryana state lies in the Indo-gangetic plains of North-west India. It has 44,212 sq.km of land and 90 per cent of this is in plains and the remaining area is in Shiwalik and Aravalli hills. Yamuna plains in the North and sandy plains in the South and West respectively have 50 per cent and 40 per cent of above land. More than 80 percent of the land is under agriculture. Canal and tube well irrigation is available for 65 per cent of arable land. Two crops per annum are a routine practice in Haryana. The climate of Haryana is arid, semi-arid and dry sub-humid. It is sub-tropical, continental and monsoonic type. The range of temperature daily as well as annual is extreme. It varies from 1°C in winter to 47°C in summer. Mean annual average temperature varies from 23°C to 26°C. May and June are the hottest months while December and January are the coldest ones. The normal annual rainfall ranges from 300 mm in the southwestern parts of Bhiwani, Hisar and Sirsa districts to about 1500 mm in the northeastern hilly tract of Ambala district. The mean daily pan evaporation ranges from 2.4 mm in December and January to 13.4 mm in May and June.

ABSTRACT

The western part of India particularly Gujarat and Rajasthan received erratic and scanty rainfall and have sandy to sandy loam soil. In such climatic and edaphic conditions failure of crop is a regular phenomenon. In such situations a cropping system is required which can protect the associated crops from extremes of climatic condition and/or provide alternative/additional income. Agroforestry has such potentials; as a result lot of research had been done on agroforestry. This paper provides some of the agroforestry system and practices, which are suitable for Gujarat. The hurdles in adoption of agroforestry and its future prospects are also provided.

INTRODUCTION

North and North-West Gujarat fall under scarcity zone, where rainfall is inadequate as well as erratic in nature. Sandy loam soils with low moisture retention capacity pose problems of low and unstable crop production and degradation due to soil erosion. Under these situation, adoption of a high yielding, more remunerative, cost effective, compatible and multipurpose system ie Agroforestry is a dire necessity.

ABSTRACT

Scattered trees/shrubs in agricultural fields or grazing fields are common features of landscape in arid regions of India. These trees were considered as insurance to the people during drought years. In recent past importance of these trees in such areas had been recognized by the scientific world. Lot of research had been made and is continuing to identify and research the tree-crop combination. This paper reviews the tested agroforestry systems in arid region of country with particular reference to Rajasthan. Economic gains due to technology intervention in agroforestry system is also given.

INTRODUCTION

The people in the arid regions of India, since time immemorial has developed location specific agroforestry systems. The scattered trees / shrubs in the agricultural fields or grazing fields are common features of the landscape. Since the beginning of cultivation the farmers deliberately allow the trees /shrubs to grow with the crops. They have screened the trees / shrubs based on their utility. They have considered that these trees are insurance to them during drought years. These trees provided lean period fodder, fruits, vegetable, timber, fuel, fiber etc. as farmers knew that occurrence of drought is common phenomenon in Rajasthan and due to failure of rains the crops failed to grow or their production is abysmally low. In the recent past efforts have been made to identify existing agroforestry systems for different agro-ecological zones (Malhotra, 1984 ; Harsh et al., 1992 ; Saxena, 1997). Efforts have also been made to study the production systems under each agroforestry systems and also to improve the existing systems through technological interventions (Harsh and Tewari, 2003; Tewari et al., 2004; Harsh et al., 2004).

ABSTRACT

Eastern part of the Uttar Pradesh falls in mid-Gangetic plain commonly called as ‘Purvanchal’. It is divided into three ecozones : i) North eastern tarai, ii) Eastern Plains, and iii) Vindhyan. Most of the farmers of the region have subsistence agriculture with small land holding. Although total forest area is 10.69 per cent of the geographical area, the actual well stocked forests (medium and good forests) in the region are confined to 3.51%. Vindhyan zone indicates higher dependence for fire wood (35% of the total need) on natural forests. Cow dung is major source used as fuel in Eastern plains (65% of the fuel requirement). The cropping systems are different in rainfed and irrigated lands. Surveys of different parts of the eastern U. P. indicate that people have a progressive attitude towards agroforestry. However, due to land hunger most of the farmers develop homesteads. Agrihorticulture system is most popular system adopted by large and medium farmers in the region. Agrisilvihorticulture system is adopted by the farmers of Eastern plains and North eastern tarai zones. Agrisilviculture, Silvihorticulture, Agrisilvihorticulture and sivipastoral systems researched by us, are recommended for adoption by the farmers.

ABSTRACT

Eastern Uttar Pradesh has 27 districts and lowest per capita net domestic output then other regions of the state. Rainfall is the only source of water. Acute shortage of fuel, fodder and timber makes agroforestry an important proposition for this region. The paper presents different agroforestry models developed by Allahabad Agriculture Institute for the region. Economics of the prominent agroforestry systems has been worked out. Emerging innovative agroforestry practices like aqua farming, honey bee, sericulture are discussed. Recommended species and agroforestry models for utilizing wastelands of the region are also provided.

INTRODUCTION

Eastern Uttar Pradesh covers an area of 87,840 sq. km. ranging from 24° - 28°20’ N latitude and 81° - 85° E longitude (map of Eastern U.P.) with population of 632 lakhs (Census, 2001). It has 27 districts and the lowest per capital net domestic output than other regions of U.P. It has 6 districts which are under developed and 15 districts are industrially backward. The contour of 100m roughly marks the western limit of Eastern Uttar Pradesh. It is mostly filled with deep alluvial deposits by the Ganga and tributaries. The Microregional variations are highlighted by the Bangar (the old alluvium) and the Khedar (new alluvium) formations. It enjoys tropical humid climate (rainfall varying from 120 cm to 140 cm). This region is plaughed with recurring floods and droughts. In 1983 Eastern Uttar Pradesh suffered a loss of the order of Rs. 319.12 crores because of the floods; in the same region, drought due to long dry spells left 3.820 lakhs ha. of sown area to wither. The menancing of Ganga – Ghaghara, Doab and recurring drought of trans Yamuna tract of Allahabad district, parts of Mirzapur and Varansi districts and big chunks of usar and unculturable wasteland (2.93 lakh ha) sap agricultural potential of these areas. Hardly 9.54 percent of total geographical area is under forests. Their paucity accenulates the problems of floods and soil erosion. Most Ganga plain is devoid of mineral wealth excepting kankar in Bhanagar tracts, but southern uplands are rich in minerals like limestone, dolomite, silica, sands, marble, building stone, magnesite and coal; organic matter is rich but nitrogen is deficient. Despite of vast water resources percentage of irrigated to gross cropped area is only 40.36 per cent that led cropping intensity only 145.20 and net irrigated to net sown area is 54.22 per cent. It has depressed economy where unemployment and underemployment is rampant, thus out migration is a typical phenomena.

ABSTRACT

Chhattisgarh is a tribal dominating state and is one of the backward and poor area of India in terms of poverty and productivity. The trees have been the part of agriculture in this region since long. The present paper highlights some of the practices which are being adopted by the farmers from time immoral and efforts had been made to fit them in the present day scientific classification system of agroforestry system with their spatial and temporal sequences. Despite of the fact that trees are integral part of farmlands still adoption of agroforestry as a sustainable land use has some constrains which have been discussed and way out suggested. Areas needed in developing agroforestry in the state have also been discussed at the end of the chapter.

ABSTRACT

Madhya Pradesh is declared as mega diversity state in India. It also harbours diversity in human population as 1/4^th of its population is tribal. These tribal people are practicing agroforestry since time immemorial. The state is divided into 11 agro climatic zones. The paper provides the agroforestry systems and species suitable for these zones. The traditional practices and the innovative agroforestry systems developed are also given. Agroforestry systems that are suitable for problematic soil have been briefly discussed. Efforts of different institutes like TFRI, JNKV and projects like TDET, ORP on Agroforestry, AICRP on AF in developing different system and their recommendations are also provided in this paper.

INTRODUCTION

Environment remained in its pristine purity and congeniality till man stayed in the hunting and food gathering stage. But, as he entered in the pastoral age and domesticated animals, he gradually passed from the nomadic stage to settled cultivation. When, he cleared the first patch of earth and upturned the first sod and lifted the first bucket of water, the long story of his interference with environment started. Clearing trees for farming, disturbing the moisture regimes and furrowing the land endangered the phenomenon of erosion leading on to the problem of reducing the soil fertility. At the same time, the art of Agroforestry emerged, though in the most rudimentary fashion, which in varying form and emphasis has continued till today. Coming to recent times, the increasing pressure on land as well as on forests, rising demand for fuel and fodder and finally the requirement of timber for multifarious purposes have strengthen the need of agroforestry as an alternate land use system especially at natural resource conservation front (Singh, 1999). Pathak (2000) opined that agroforestry is a land management system that optimizes the overall land productivity and reduces resources depletion through the utilization of positive interactions between crops-trees-animals in its temporal and spatial dimensions. In this way, agroforestry operates in a given socioeconomic frame work; it is not a static but a dynamic structure.

ABSTRACT

Maharashtra ranks second in terms of area under tree cover, however, still large chunk of land is lying without use or are underutilised because of their degradation status. Such degraded lands can be put to use through agroforestry. Agroforestry is being adopted in this state in one way or the other by raising trees on farm bunds, around cattle sheds etc. since earlier times. New innovative technology has now been developed by all the agricultural universities of state. The paper provides detailed information of different agroforestry systems which have been developed and practised in the state.

INTRODUCTION

Maharashtra is the third largest state of India having the geographical area of 307,713 km², which constitute 9.4 per cent of the country’s geographical area. The human population of the state is 96.75 million (9.4% of country’s population) of which 57.6 per cent is rural and 42.4 per cent is urban. The average population density is 314 persons per km². The tribal population is 9.3 per cent of the state population. The state supports livestock population of 36.4 million, which is 7.7 per cent of the country’s livestock population. The state rank second amongst all the state/UTs in terms of area under tree cover and third in term of recorded Forest Area (Anon, 2001).

ABSTRACT

Bihar is a state whose economy is solely dependent on agriculture. Though it has deep fertile land of alluvial origin, still agriculture of this state is facing problems due to frequent flooding. Population pressure on forest had led to creation of large extent of degraded lands. Agroforestry seems to be one of the viable option to avert these adverse conditions. Traditionally people used to integrate trees in farm lands in different forms. However, green revolution reduced these practices. The present paper provides a detailed account of prevalent agroforestry practices in Bihar. Results of different agroforestry systems which had been researched under AICRP on Agroforestry in Bihar since 1987 are also given in this paper.

INTRODUCTION

Bihar, the twelth largest state of India is bound on the north by Nepal, south by Jharkhand, east by West Bengal and on the west by Uttar Pradesh. The state lies between 24° 20’10″ to 27° 31’15″ N latitude and between 83° 19’50" to 88° 17’40"E longitude at an elevation of 53.12 m above the mean sea level and comprises an area of 93595.68 sq.km. The topography of Bihar is practically plain. The whole of the Bihar plain is traversed by a number of fairly large rivers, viz., Ganga, Ghagra, Kosi, Bagmati, Burhi Gandak, Kamla balan etc. which cause intermittent floods and engulf several districts of Bihar each year.

ABSTRACT

The paper gives a comprehensive detail of the state with regards to its inception, socio-economic, climatic and edaphic conditions. In addition states agroclimatic zones along with their characteristics have been described in the paper. Extent of agriculture crops, horticulture, animal husbandry, fisheries and forestry along with their production and contribution to national pool is provided elaborately. Details of agroforestry systems like silvipastoral and agrisilvipastoral for land with very high erosion and hortisilviculture and hortiagrisilviculture, aquaforestry, entomoforestry recommended for land with moderate to low erosion had been explained in details. Significant results obtained in agroforestry research under AICRP on Agroforestry and Horticulture and Agroforestry Research program have also been presented in this paper. Finally some tips to make agroforestry successful and future strategies have been given.

INTRODUCTION

Jharkhand state evolved as 28^th State on 15^th November 2000 from the southern part of Bihar, with a total area of 79.5 lakh ha and population density of 274/Km² consisting of 28 per cent schedule tribes and 12 per cent schedule caste population. A total of 29.61 per cent of the geographical area of the state consists of forest area with 28.4 per cent actual forest cover (Annon., 2001). Most of the forest area of the state consists of mines, which do not allow any agriculture. The continued large-scale mining operations of Coal and Iron ore are generating serious threats for the area coming under down streams. The areas lying under sharp undulating topography are under threats of soil erosion, which in turn affect the low lying water body’s carrying capacity i.e. due to continuous siltation, all such anomalies emphasizes the need to improve the water and land use efficiency in order to ensure better storage and retention of the rain water, for improving the productivity of the land.

ABSTRACT

West Bengal is the gateway to North-East and has diverse vegetation and social strata. The paper presents the agroclimatic zones of the state along with their characteristic features. The scenario with regard to agriculture, forest cover and livestock shows that practicing agroforestry is the need of the state. For the sake of convenience the state has been divided into two parts: south Bengal and north Bengal. In the tribal dominated parts of the state home gardens are prevalent. Possible interventions in the present land use along with strategies to increase tree cover under agroforestry has also been discussed.

INTRODUCTION

Cultivation of tree species and agricultural crops in intimate combination had been a practice through out the world at one period or another. Trees were integral and important component of the farming system. However, in the middle ages the concept changed and agriculture, forestry and animal husbandry were separated under a monoculture management system. This in long run led to an incredible reduction in forest cover and ecological imbalance. Scientists and managers once again began to think about changing the land use system and integrating trees with agriculture crops (Panwar et al., 2004). In India, research work on agroforestry was initiated during the late 1970’s by Indian Grassland and Fodder Research Institute, Jhansi; Central Soil and Water Conservation Research and Training Institute, Dehradun; Central Arid Zone Research Institute, Jodhpur and ICAR Research Complexes in isolation. National commission on agriculture also emphasized starting of agroforestry education in all agriculture university. The formal research activities related to agroforestry started in a big way with the initiation of All India Coordinated Research Project on Agroforestry (AICRPAF) from 7^th Feb., 1983 with 20 centers, of which 12 were in State Agricultural Universities and rest in ICAR Institutes. Later more centers were added. The major emphasis was to have research centers in all the major ecological zones of India. In this venture in the first phase AICRPAF was initiated in West Bengal at Jhargram, Distt. Midnapore under the auspices of the then only Agricultural University in West Bengal - Bidhan Chandra Krishi Viswavidyalaya, Mohanpur representing Humid and Subhumid zone of West Bengal.

ABSTRACT

Orissa is traditionally an agrarian state. It is endowed with vast natural resources, diversified agro-edaphic conditions,rich flora and fauna, wide range of land holdings, various socio-cultural groups and people with multiple economic strata. These factors have led to evolve a variety of agroforestry systems and practices. The traditional agroforestry systems which are prevailing in the state since time immemorial are broadly agrisilvicultural, silvipastoral and agrisilvipastoral systems. The prominent agrisilvicultural systems include podu/jhum cultivation, multipurpose trees on farm lands, multiple species tree gardens and agroforestry for fuel wood production. The important silvipastoral systems are trees on pasture, fodder trees and shrubs on forest land and live fence of fodder trees and shrubs. The very old agrihortisilvicultural system prevailing in the state is homegarden. Interventions of Orissa University of Agriculture and Technology and various Government and Non-Government agencies have resulted in the development of some improved agroforestry practices in recent years. Some of the improved agroforestry practices are Acacia mangium based agrisilvicultural practices, Guava based agrisilvicultural practices, coconut based agroforestry practices, Eucalyptus (Clonal) based agrisilvicultural practices, windbreaks, timber tree based agrisilvicultural practices, Sesbania grandiflora based agrisilvicultural practice, Acacia mangium based silvipastoral system, mangium-guava based silvipastoral practices, improved homegardens, commercial block plantations on farmlands and apisilvicultural practice.

ABSTRACT

Assam has been divided into six agroclimatic zones on the basis of soil, climate, terrain and vegetation. It comprises of Brahmaputra plain zone to Hill zone. The paper deals with the traditional agroforestry systems prevailing in all these agroclimatic zones along with the research activities which are going on in Assam. Salient research achievements with respect to tree-crop compatibility are given at the end of the chapter. Impact of agroforestry research on farmers of Assam in terms of adoption is also given.

INTRODUCTION

Assam, one of the eastern states of India, lies between 240 N and 28018’ N latitudes and 8904’ E and 960 E longitudes. The state is surrounded by Bhutan and Arunachal Pradesh in the north, Nagaland, Manipur and a part of Arunachal Pradesh in the east, Mizoram, Tripura and Meghalaya in the south and West Bengal in the west. The state is endowed with abundant fertile land and water sources with a total geographical area of 78,523 km² with population density of 318 per square kilometer.

ABSTRACT

In the state of Meghalaya, forests are being degraded by age-old practice of shifting agriculture by native tribes and other human activities. Agroforestry has a great potential both from the point of view of restoration and maintenance of soil fertility and to increase agriculture production. The traditional system of agriculture in the state is primitive, labour intensive and dependent on rainfall. The proportion of space occupied by the tree and crop components in the traditional system largely depends upon factors like soil types, plant species and crop arrangements. The common traditional systems practiced in the state may be grouped under agrisilviculture, agrihorticulture, silvihorticulture, pastoralsilviculture and pastoralhorticulture. Agroforestry systems can play an important role in soil conservation and improvement in moisture and nutrient levels through efficient cycling of nutrients, which in turn would enhance agriculture production. The analysis of different agroforestry systems in the state of Meghalaya suggests that further improvement of the existing systems may yield high productivity and make them more sustainable.

INTRODUCTION

Agroforestry is an ideal scientific approach to tackle the problems of degraded lands and to bring about eco-restoration and maintenance of soil resources. The significance of tree based land use systems in general and agroforestry in particular, has been realized in improving the economy of farmers having small land holdings (Chauhan and Dhyani 1990, Beer et al 1990, Fisher 1990, Dhyani and Tripathi 1999). The fertility of soils can be improved under the influence of tree cover, which checks erosion, contributes to accumulation of organic matter content, adds nitrogen through symbiotic N-fixation by leguminous or actinorrhizal trees and continuously replenishes the nutrients through effective recycling mechanisms. It offers a practical means of achieving greater outputs and at the same time maintains soil fertility that ultimately helps in increasing productivity of agricultural crops and trees.

ABSTRACT

Mizoram is predominantly a hilly state where people have been practicing agroforestry in a variety of forms from traditional shifting (jhum) cultivation to the most scientific-induced agroforestry models. However, ‘jhum’ still remains the main form of land use even though it is known to cause severe soil, water and biodiversity erosion and low crop productivity. The induced agroforestry practices carried out in Miozram have the ability to replace shifting cultivation but these systems again are not properly designed to tackle various biophysical, socio-cultural and economic need of the people, resulting in their poor acceptability. The paper reviews various agroforestry systems prevailing in Mizoram and details some ongoing agroforestry research trials in the State.

ABSTRACT

Arunachal Pradesh, the largest state of North-East India is unique state of the country in the sense that its altitude range between 70 – 7000 m, have 26 major tribes besides 110 sub-tribes, have 82 per cent of its land under forest and most of the area is under the control of local tribes which practice shifting cultivation. The paper presents the potentialities of agroforestry in Arunachal Pradesh. The different agroforestry systems prevailing in the state are also given in detail. Agroforestry systems which are scientifically tested and the direction in which research are to be done in future to extend agroforestry has also been presented.

INTRODUCTION

Indian Eastern Himalaya, covers the states of Assam, Sikkim, Arunachal Pradesh, Nagaland, Mizoram, Manipur, Tripura and Meghalaya (Kukreti, 2000). The erstwhile North East Frontier Agency, now Arunachal Pradesh, the largest state among the North-eastern states of India lies at latitude 26°28’-29°30 N and longitude 91°30’- 97°30 E with a geographical area of 83,743 km². The human population of the state is 10,91,113 (GOI, 2002). The recorded forest area in the state is 68602 km² which is 82.0 per cent of the geographical area of Arunachal Pradesh (Kukreti, 2000). The forest cover in the state forms the highest amongst all the states of the country and state is least densely populated. The state is bounded by Bhutan to the west, Myanmar to the east, China to the north and north east, and the plains of Assam to the south. There are 26 major tribes and 110 sub tribes which inhabit different parts of the state, with a life style totally dependent on the forest resources. Moreover, almost all the major tribes and sub tribes has been practicing shifting cultivation from the ancient time in this region which is integral part of sociocultural life of the tribal people.

ABSTRACT

Homegardens are traditional agroforestry systems present throughout the northeast India especially in foothill region. The high diversity and the intensive care that is given to the homegarden in and around Arunachal Pradesh results in a unique combination of high levels of productivity, stability and sustainability of the system. The homegardens studied here were vertically distributed in four different layers viz, floor, middle, sub-canopy and canopy. Such stratification has given rise to the distribution of a variety of species based on light requirement in the system. Density and diversity index of tree species in the homegardens were highest in Harmutty in the foothills (468.5 plants ha^-1 and 1.17 respectively), whereas lower values were recorded in Ziro in the upper elevation (16 plants ha^-1, 0.651 respectively). Soil nutrients were greater in Harmutty, followed by Doimukh, Nirjuli and then Ziro. Maximum plant detrital (litter and fine roots) biomass and their subsequent decomposition in the homegardens of Harmutty (10185.67 kg ha^-1) might be the probable reason for the efficient nutrient cycling and generation of more available nutrients.

ABSTRACT

Homegarden is a least studied agroecosystem of the world. Present study, conducted in 430 homegardens before Tsunami in five island groups namely North Andaman, Middle Andaman, South Andaman, Car Nicobar and Noncowry (former three, Andaman group and later two, Nicobar group of islands), India, reports composition, species structure and its distribution and functioning of the system. The homegarden is comprised of 6 components i.e., garden, livestock, poultry, fishpond, homesteads, and rice fields. Coconut and arecanut trees predominate in the garden. Fruits, spices and agroforestry trees are other ligneous species, which together with the former trees form multistorey canopy structure. But, composition and dominance of the tree species vary across the islands. Arecanut to coconut ratio is greatest invariably in all the homegardens in the Andaman. Family members do maximum 70 per cent labour in the homegarden and consume 35-65 per cent fruits, poultry, livestock and fishpond products, however, surplus is sold. Free range grazing in nearby protected forests is an age old practice of animal feeding whereas poultry birds are fed among the garden trees and household refuge. Livestock includes cattle, buffaloes and goats in Andaman and pig and goat in Nicobar. Cattle are used for milk, he buffaloes as a draft animal and pig and goat for meat. Cattle, mostly local breed, yield a little amount of milk, an average, 1 liter cow-1. Plantation crops production is low: coconut 18-30 nuts palm^-1 and arecanut 0.75 kg palm^-1. The homegardens serve the subsistence as well as earn income, but low (US$ 2357) to the house. In Nicobar, Nicobarese huts interspersed in a big natural coconut plantation form the homegarden. Tribe Nicobarese do not know crop husbandry, rather they pursue round the year sea fishing and pig rearing. They relish most pork, unripe boiled wild banana, Nicobari tuber, fruits and seeds of Pendanus and fried fish.

ABSTRACT

Andhra Pradesh is predominently an agrarian state, where 70 per cent of the people live in rural areas. Andhra Pradesh has 7 Agroecological zones spread over in coastal Andhra, Telangana and Rayalaseema regions with varied climatic situations. The existing agroforestry systems in costal Andhra are Mango-based Agrihorticulture system, Betelvine-sesbania system, Borrasus flabellefer, Glyrecidia boundary plantations, Eucalyptus, Causarina and Subabul block plantations. Besides Neem, Tamarind and jamuns are also found in isolated manner. In Telangana region, Custard apple based Agrihorticulture system, Mango based Agrihorticulture system, Boundary plantations of Neem, teak, Jamun etc., are present. Eucalyptus based Agrisilviculture system is propagated by ITC, Bhadrachalam in Khammam and elsewhere in the state. In Rayalaseema region in all the districts tamarind, mango and sweet orange based agroforestry systems are prominently seen. The betelvine - sesbania system alone is fetching an income of 100 crores/year to the states’ exchequer. The common trees and tree systems available in the state are : Azadirachta indica, Tamarindus indica, Acacia nilotica, Pithecellobium dulce, Parkinsonia aculeata, Pterocarpus santalinus, Dalbergia latifolia and many others.

ABSTRACT

Agroforestry a sustainable land use system being practiced since long back through out the country. A diverse climatic, edaphic, and environmental conditions prevailing in the country has made it possible to practice different kinds of agroforestry systems. The local research organizations and individuals have undertook various studies for the betterment of the local agroforestry systems for getting higher yields to meet the need of food, fodder, fuel wood etc. It was found that Jowar+Teak+Papaya followed by Chilli+Teak+Papaya combination gave more economic returns compared to pure agricultural crop. Casuarina equisetifolia, Grevillea robusta, Dalbergia sissoo and Melia dubia have been found to be suitable for agroforestry systems in dryland. Coffee based agroforestry system and other tree-crop combination tried have been elaborated in this paper.

INTRODUCTION

Agroforestry is a new word for the old practice of growing woody plants with agricultural crops and/or livestock together on the same land. Various experts and scientists working on agroforestry or involved in land use related sciences have defined agroforestry according to their individual understanding of what they call agroforestry.

“Agroforestry is sustainable management system for land that increases total production, combines agricultural crops, tree crops and forest plants and or animals simultaneously or sequentially and applies management practices that are compatible with the cultural patterns of the local population” (Chundawat and Gautham, 1993).

ABSTRACT

Agroecologically the state is divided into 13 zones based on altitudinal variations, precipitation pattern, soil type and topographic features. Land use systems that integrate woody perennials with other life forms abound in all these zones, along with a great diversity of trees and field crops. Although these practices are apparently specific to the topographic and edaphic factors, a complex pattern of overlapping which transgresses over a wide range of agroecological zones is obvious. An attempt is made to describe the important agroforestry systems of Kerala, both traditional as well as those potentially suitable.

INTRODUCTION

The state of Kerala with many woody perennial-based land use practices is often regarded as the “Mecca” of agroforestry. Most of these are, however, traditional systems evolved over centuries of cultural and biological transformations and may represent the accrued wisdom and insights of farmers who have interacted with environment, without access to exogenous inputs, capital or scientific skills. Over long periods in the history of land use in these highly populated humid tropical lands, such diverse land use systems have apparently remained as engines of food security, besides sourcing multiple products and services including certain intangible benefits (e.g., microclimatic modification, soil and water conservation); thus providing the rationale for the co-existence of an array of pluralistic land use orders often in close juxtaposition with one another. Yet another plausible explanation for the occurrence of many diverse woody perennial-based systems and practices over a relatively small geographical range is perhaps the brute heterogeneity of the Kerala landscape.

ABSTRACT

Tamil Nadu, the southern most state of India has 8 per cent of the country’s population and its net sown area is only 4-5 per cent of the country’s area. The state is endowed with varied physiography from hills to coastal lands and hence varied agroclimatic and edaphic conditions. This paper details the characteristics of different agroclimate and provides varied perennial and annual components being practiced in different combinations in these agroforestry systems.

INTRODUCTION

Land is a major non renewable natural resource. With the increase in population, the demand of land for all activities increases. The requirement of food, fibre, fodder and fuel of the ever increasing population has to be met with the finite land resources. In India, the pattern of land use in agriculture and forestry took a drastic turn during the period from fifties to eighties. Conservation, development and management of the available land is basic for ensuring food, ecological, environmental and economic security of our country. Tamil Nadu’s population is around 8 per cent of the total country and the net sown area is only a meager 4-5 per cent of that of the country. With the ever increasing population and expanding industrialization, steps need to be taken to utilize the land to the optimum extent possible and to identify and utilize lands effectively and efficiently in order to make full use of their maximum capability.

ABSTRACT

Modelling has been used in natural sciences since centuries in one-way or the other. However, system modelling as a discipline in itself is established in the recent years. Agroforestry modelling is a complex process that essentially involves at least two elements viz. tree and crop, where tree is the long term and crop is the short-term component. Agroforestry models, usually, predict tree growth and yield and the reduction/enhancement in crop yield as influenced by the tree component in temporal and spatial sequence. In this paper the need of modeling, stages of model development, its validation and classification of models are given. The models, which are relevant to agroforestry, have also been given.

INTRODUCTION

Agroforestry combines agriculture and forestry technologies to create more integrated, diverse, productive, profitable, healthy and sustainable land use systems. According to the Association for Temperate Agroforestry - “Agroforestry practices are intentional combinations of trees with crops and/ or livestock that involve intensive management of the interactions between the components as an integrated agroecosystem”. These key characteristics are the essence of agroforestry and are what distinguish it from other farming or forestry practices. To be called agroforestry, a land use practice must satisfy all of these criteria:

ABSTRACT

The popularity and belief in natural and herbal healthcare systems is inseparable from traditional ethos and practices in India. India has been known to be a rich repository of medicinal plants since time immemorial. Now many countries like China, Cuba, India, Sri Lanka, Thailand etc. have endorsed the official use of traditional system of Medicines in their healthcare programmes. The western system of medicine (allopathy) too has a large component of plant based drugs and most potent medicines use specific chemical constituents which in turn has generated bulk demand. A dramatic increase in exports of MAP’s (medicinal and aromatic plants) attests to global interest in their products as well as in the traditional health system. Past efforts of 27 years in agroforestry research and extension is now yielding results; Agroforestry is coming up in private as well as community lands in a big way for both subsistence as well as commercial purposes. Incorporation of medicinal plants in agroforestry will not only diversify the cropping system but will also lead to conserve and reduce pressure on medicinal plants in forest besides improving economic status of the farmers.

ABSTRACT

The integration of woody perennials on the farm lands for obvious reasons has been the common practice with the farming community for ages. It is true that the integration of trees on the farmland, albeit paves the way for the improvement of existing system, but nevertheless creates complex biological interactions, which may not necessarily result in yield advantage. Management of multipurpose tree species, especially agroforestry tree species, integrated on the farmland with crops, is essential for two reasons, i) because canopy size decides the transmission of photosynthetically active radiation to the understorey crops and ii) that the impact of canopy management practices some times have drastic implications. Canopy management practices like coppicing; pollarding and partial crown removal not only affects foliage and branch wood biomass production but also modifies physiological parameters and resource utilization pattern. This paper deals with the need and techniques of managing canopy as well as the research activities carried out in this regards.

ABSTRACT

Women nearly constitute half of the population of the mountainous region of northwestern Himalayas. Rural hill women with their multiple roles and functions in the society, form an integral part of sustainable development of hills. Irrespective of age and health, they have to perform domestic household and agriculture work. Collection of fodder, firewood and fuel wood from the forest areas for energy requirements and household cooking are also done by women. The present paper provides the background information about the women in hilly areas and their dependence on agroforestry for meeting daily requirements of household.

INTRODUCTION

More than ninety per cent of mountain population inhibit in rural areas. Women nearly constitute half of the population of the region having composite social profile. Mountain specificities which consists of habitats, societies and their interactions and adaptations can prove to be constraints as well as opportunities. Comparative economic growth or development and dynamism in social-economic structure are due to interlinking of various land use systems including agriculture, horticulture, forestry, animal husbandry and tourism. Rural women play a pivotal role in sustainable development of their areas and form an integral part of subsistence rural economy (Thakur, 2003). They are considered nucleus of hill farming because of their multiple functions/ role in the society. Hence this section of the society in the region is the main and basic asset. They depend on their surrounding environment for many of the basic needs, therefore they are inextricably linked with natural resources and environment, and thus have to cope with the harsh environment by developing mountain specific adaptations.

ABSTRACT

The paper discusses distribution of bamboo, their uses and bamboo based agroforestry systems in India and their future potential. Bamboo, one of the fastest growing plant species is extremely versatile and has been traditionally put to a large number of uses. Application of modern technology and industrial processing has catapulted bamboo into a new global limelight. At present there is huge demand of bamboo based raw material viz., timber, plywood, bamboo flooring, edible bamboo shoots, etc. in the international market and most of the international market of bamboo is captured by China. In India, most of the bamboo raw material comes from natural forest. To capture the emerging bamboo market we have to increase the bamboo cultivation outside the forest under different bamboo based agroforestry systems. Experiments have shown that bamboo based agrisilviculture systems is technically and economically feasible in our country under different agro-ecological conditions. The agriculture crops which can be profitably grown with bamboo are soybean, pigeon pea, ginger, turmeric, etc. Keeping in view the international scenario, ecological conditions and taking clues from China’s success stories, some of the bamboo based agroforestry system components are also proposed.

ABSTRACT

Minerals are important raw materials for the economic development of any nation. However, unscientific mining for minerals poses a serious threat to the environment. Mine spoils from outer Uttaranchal Himalaya are highly variable from loose to hard and compact at places. Rehabilitation technology for degraded mine sites consist of several steps, each of them playing an important role. Rehabilitation of these spoils is imperative to meet our demand of fuel, fodder, timber, reduce soil erosion and improve environmental pollution. The paper presents the efforts of rehabilitation of mine spoils in Uttaranchal Himalayas both mechanical as well as vegetative measures. Agroforestry techniques used in rehabilitation of mine spoils has been given in this paper.

INTRODUCTION

Himalayan region which constitute about 54 million ha (16.5%) area of the country is characterized by marginality, inaccessibility and fragility, compounded by high intensity erratic rainfall, steep slopes, large scale deforestation and faulty management practices. Natural resources in the region are under great stress due to mounting human and livestock populations. The increasing frequency of natural disasters, e.g. landslides, floods, droughts and deterioration of water bodies due to accelerated deforestation, conversion of marginal/forest land into agriculture and unscientific developmental activities e.g. mining, roads etc. further aggravate the problem. Soil erosion is the major constraint in crop production. High intensity rains in the monsoon season cause excessive runoff and soil loss. On erosion-prone steep slopes, about 50 per cent of the rainfall is lost as runoff, carrying with it 20 t ha-l soil.

ABSTRACT

In agroforestry and forestry sectors, little efforts have been made for tree improvement research in India. Planting of genetically poor quality of seedlings/propagules is one of the major reasons of low level impact of agroforestry systems in Indian Agriculture. Most of the agroforestry tree species have not been even gone through simple selection for superior types (plus trees). Exploration, collection and conservation of germplasm of woody agroforestry species, selection for fast growing trees, clonal propagation, seed orchards and other advances in tree breeding are still in fancy stage. At present, all the woody agroforestry species are propagated through collected seeds and/or propagules by unskilled labourers. It is well known that through tree breeding and establishment of seed orchards of improved genotypes, significant achievements towards the improvement of productivity of economic tree products is possible as happened in agricultural crops in India and industrial trees in USA and Europe. Even by small efforts of tree improvement, productivity of economic tree products can be raised by 20-30 per cent. In this paper breeding methodology, limitations, status and strategy of various agroforestry species has been discussed in special reference to Leucaena leucocephala (Subabul), Prosopis cinereria (Khejri), Azadirachta indica (Neem), Populus spp., Dalbergia sissoo (Shisham), Acacia nilotica (Desi babul), Eucalyptus spp. Casuarina equisetifolia (Casuarina), Albizia lebbek (Desi siris) and Jatropha curcus (Ratanjot).

ABSTRACT

Contour hedgerow technology has different names in different regions. Sloping Agriculture Land Technology (SALT) has alley farming with hedgerow barrier technology. It is basically an agroforestry system in which nitrogen - fixing trees or shrubs are planted very closely in rows and cash crops grown in between the alleys. The SALT has been considered as an alernative to shifting cultivation. Forest dwellers are mostly tribals and shifting cultivation have been their practice for food production. The slash and burn has caused enormous damage to the forest composition. The forests on the hills and on the mountains have suffered a lot due to “Podhu” cultivation. The similar situations have been observed also in most of the Asian country. The hilly area has been considered under the hedgerow system for soil and water conservation. The introduction of the agroforestry systems in the farmers fields and in the wastelands have brought potential forest farming. The young leaves of some hedge row plants provide good fodder for livestock. Hedgerows can also be managed to provide fuelwood, if necessary. The hedgerows and their trimming provide mechanical and biological barriers and help minimise soil erosion by reducing surface runoff velocities, leading to higher deposition of soil sediments and living source of nutrient cycling. The food and cash production has been observed to be the most essential components in four types of SALT models.

What is Nanotechnology? Answers differ depending on who you ask, and their background. Broadly speaking however, nanotechnology is the act of purposefully manipulating matter at the atomic scale, otherwise known as the “nanoscale.” Coined as “nano-technology” in a 1974 paper by Norio Taniguchi at the University of Tokyo, and encompassing a multitude of rapidly emerging technologies, based upon the scaling down of existing technologies to the next level of precision and miniaturization. Taniguchi approached nanotechnology from the ‘top-down’ standpoint, from the viewpoint of a precision engineer.

Foresight Nanotech Institute Founder K. Eric Drexler introduced the term “nanotechnology” to the world in 1986, using it to describe a ‘bottom-up’ approach. Drexler approaches nanotechnology from the point-of-view of a physicist, and defines the term as “large-scale mechano synthesis based on positional control of chemically reactive molecules.” In the future,“ nanotechnology” will likely include building machines and mechanisms with nanoscale dimensions, referred to these days as Molecular Nanotechnology (MNT).

Nanomaterials are a field which takes a materials science-based approach to nanotechnology. It studies materials with morphological features on the nanoscale, and especially those which have special properties stemming from their nanoscale dimensions. Nanoscale is usually defined as smaller than a one tenth of a micrometer in at least one dimension, though this term is sometimes also used for materials smaller than one micrometer.

An aspect of nanotechnology is the vastly increased ratio of surface area to volume present in many nanoscale materials which makes possible new quantum mechanical effects, for example the “quantum size effect” where the electronic properties of solids are altered with great reductions in particle size. This effect does not come into play by going from macro to micro dimensions. However, it becomes pronounced when the nanometer size range is reached. A certain number of physical properties also alter with the change from macroscopic systems. Novel mechanical properties of nanomaterials are a subject of nanomechanics research. Catalytic activities also reveal new behaviour in the interaction with biomaterials.

A semiconductor is a material that has an electrical resistivity between that of a conductor and an insulator.

A semiconductor is a substance, usually a solid chemical element or compound that can conduct electricity under some conditions but not others, making it a good medium for the control of electrical current. Its conductance varies depending on the current or voltage applied to a control electrode, or on the intensity of irradiation by infrared (IR), visible light, ultraviolet (UV), or X rays.

An external electrical field changes a semiconductor’s resistivity. Devices made from semiconductor materials are the foundation of modern electronics, including radio, computers, telephones, and many other devices. Semiconductor devices include the transistor, solar cells, many kinds of diodes including the light–emitting diode, the silicon controlled rectifier, and digital and analog integrated circuits. Solar photovoltaic panels are large semiconductor devices that directly convert light energy into electrical energy. In a metallic conductor, current is carried by the flow of electrons. In semiconductors, current can be carried either by the flow of electrons or by the flow of positively–charged “holes” in the electron structure of the material.

Polymeric nanoparticles are nanoparticles which are prepared from polymers. The drug is dissolved, entrapped, encapsulated or attached to nanoparticles and depending upon the method of preparation, nanoparticles, nanospheres or nanocapsules can be obtained. Nanocapsules are vesicular systems in which the drug is confined to a cavity surrounded by a polymer membrane, while nanospheres are matrix systems in which the drug is physically and uniformly dispersed.

In recent years, biodegradable polymeric nanoparticles have attracted considerable attention as potential drug delivery devices in view of their applications in drug targeting to particular organs/tissues, as carriers of DNA in gene therapy, and in their ability to deliver proteins, peptides and genes through oral route of administration.

In spite of development of various synthetic and semi synthetic polymers, natural polymers still enjoy their popularity in drug delivery, some of them are: gums (Eg. Acacia, Guar, etc.,) chitosan, gelatin, sodium alginate, and albumin. A range of materials have been employed to delivery of bioactive agents. A polymer used in controlled drug delivery formulation, must be chemically inert, non-toxic and free of leachable impurities. It must also have an appropriate physical structure, with minimal undesired aging, and be readily processable. Some of the polymeric materials are: cellulosics., poly(2-hydroxyethyl methacrylate), poly(N-vinyl pyrrolidone), poly(methyl methacrylate), poly(vinyl alcohol), poly(acrylic acid), polyacrylamide, poly(ethylene-co-vinyl acetate), poly(ethylene glycol), poly(methacrylic acid).

“Small is beautiful”, today we know that small is not only beautiful but also powerful. With the range of applications that nanoparticles find in varied fields of engineering and science, nanoparticles seem a promising option when compared to the conventional materials used. Nanoparticles are particles that have at least one dimension in less than 100nm range. They have a high surface to volume ratio and thus mass transfer and heat transfer properties are better than bulk materials. Recently; core/shell nanoparticles are finding widespread application. There is a class of core/shell nanoparticle that has its entire constituent in the nanometer range. Core/shell nanoparticles are nanostructures that have core made of a material coated with another material. They are in the size range of 20nm-200nm. Also, composite structures with these core/shell particles embedded in a matrix material are in use. The necessity to shift to core/shell nanoparticles is the improvement in the properties. Taking into consideration the size of the nanoparticles, the shell material can be chosen such that the agglomeration of particle can be prevented. This implies that the monodispersity of the particles can be improved. The core/shell structure enhances the thermal and chemical stability of the nanoparticles, improves solubility, makes them less cytotoxic and allows conjugation of other molecules to these particles. The shell can also prevent the oxidation of the core material. “When a core nanoparticle is coated with a polymeric layer or an inorganic layer like silicabecausethe polymeric orinorganiclayerwould endow the hybrid structure with an additional function/property on top of the function/property of the core hence synergistically emerged functions can be envisioned”.

A fullerene is any molecule composed entirely of carbon, in the form of a hollow sphere, ellipsoid, or tube. Spherical fullerenes are also called buckyballs, and cylindrical ones are called carbon nanotubes or buckytubes. Fullerenes are similar in structure to graphite, which is composed of stacked graphene sheets of linked hexagonal rings; but they may also contain pentagonal (or sometimes heptagonal) rings.

The first fullerene to be discovered, and the family’s namesake, was buckminsterfullerene C₆₀, made in 1985 by Robert Curl, Harold Kroto and Richard Smalley. The name was homage to Richard Buckminster Fuller, whose geodesic domesit resembles. Fullereneshave since been found to occur (if rarely) in nature.

The discovery of fullerenes greatly expandedthe numberof known carbon allotropes, which until recently were limited to graphite, diamond, and amorphous carbon such as soot and charcoal. Buckyballs and buckytubes have been the subject of intense research, both for their unique chemistry and for their technological applications, especially in materials science, electronics, and nanotechnology.

There aremany different points of view aboutthe nanotechnology. These differences start with the definition of nanotechnology. Some define it as any activity that involves manipulating materials between one nanometer and 100 nanometers. However the original definition of nanotechnology involved building machines at the molecular scale and involves the manipulation of materials on an atomic (about two-tenths of a nanometer) scale.

The debate continues with varying opinions about exactly what nanotechnology can achieve. Some researchers believe nanotechnology can be used to significantly extend the human lifespan or produce replicator-like devices that can create almost anything from simple raw materials. Others see nanotechnology only as a tool to help us do what we do now, but faster or better.

The third major area of debate concerns the timeframe of nanotechnology-related advances. Will nanotechnology have a significant impact on our day-to-day lives in a decade or two, or will many of these promised advances take considerably longer to become realities?

Finally, all the opinions about what nanotechnology can help us achieve echo with ethical challenges. If nanotechnology helps us to increase ourlifespans orproduce manufactured goodsfrom inexpensive raw materials, what is the moral imperative about making such technology available to all? Is there sufficient understanding or regulation of nanotech based materials to minimize possible harm to us or ourenvironment? Only timewill tell how nanotechnology will affect our lives.

Atoms and molecules are the essential building blocks of every object. The manner in which things are constructed with these basic units is vitally important to understand their properties and their reciprocal interactions. An efficient control of the synthetic pathways is essential during the preparation of nanobuilding blocks with different sizes and shapes that can lead to the creation of new devices and technologies with improved performances. Traditionally nanoparticles were produced only by physical and chemical methods. Some of the commonly used physical and chemical methods are ion sputtering, solvothermal synthesis, reduction and sol gel technique

Basically there are two approaches for nanoparticle synthesis namely the Bottom up approach and the Top down approach. In the Top down approach, scientists try to formulate nanoparticles using larger ones to direct their assembly. The Bottom up approach is a process that builds towards larger and more complex systems by starting at the molecular level and maintaining precise control of molecular structure.

These two different methods highlight the organization level of nanosystems as the crossing point hanging between the worlds of molecular objects and bulk materials.

The top-down approach has been advanced by Richard Feynman in his often-cited 1959 lecture stating that “there is plenty of room at the bottom” and it is ideal for obtaining structures with long-range order and for making connections with macroscopic world. Conversely, the bottom-up approach was pioneered by Jean-Marie Lehn (revealing that “there is plenty of room at the top”) and it is best suited for assembly and establishing short-range order at the nanoscale. The integration of the two techniques is expected to provide, atleast in principle, thewidest combination of tools for nanofabrication.

It is classified asbottom-up manufacturing which involves building up of the atomor molecular constituents asagainstthetop methodwhich involves making smaller and smaller structures through etching from the bulk material as exemplified by the semiconductor industry.

Chemical synthesis is spontaneous organization of molecules into stable, structurally well-defined aggregates at the nanometer length scale. Chemical synthesis is largely an art form (i.e., theory often does not quantitatively predict how to make new materials from molecules).Yet, chemical synthesis can be quite powerful (e.g., proteins and complex organic molecules can be made from simple reagents) Semiconductor nanocrystals have been synthesized via “natural self-assembly” in two steps:

1.Capped cluster molecule forms spontaneously from molecular reagents in solution

2.Cluster molecules crystallize out of solution

Nanoparticles synthesis is done by two major routes, which include classical synthesis and green synthesis. The green synthesis techniques generally utilize relatively non-toxic chemicals non-toxic solvents, biological extracts and systems. Biological methods are considered safe and ecologically sound forthe nanomaterial fabrication asan alternative to conventional physical and chemical methods

Nanoparticles

Gold, silver, and copper have been used mostly for the synthesis of stable dispersions of nanoparticles, which are useful in areas of photography, catalysis, biological labeling, photonics, optoelectronics and surface-enhanced Raman scattering (SERS) detection

The need for biosynthesis of nanoparticles rose as the physical and chemical processes were costly. So in the search of cheaper pathways for nanoparticle synthesis, scientists used microorganisms and then plant extracts for synthesis. Nature has devised various processes for the synthesis of nano- and micro- length scaled inorganic materials which have contributed tothedevelopment of relatively newandlargely unexplored area of research based on the biosynthesis of nanomaterials.

The most commonly used technique has been discussed and we have tried to generalize the type of particle that can be synthesized by each of these methods. Though it is not a rule that is applicable to all cases but it can be applied to most cases.

Polymerization Radical Polymerization

The polymerization could be a free radical polymerization or an atom transfer radical polymerization. The process of atom transfer radical polymerization (ATRP) is better than the free radical polymerization as control of molecular weight and size of the particle can be achieved. The coating of polymer on silica nanoparticles is generally done by ATRP. The surface of the silica particle is modified with a suitable initiator.

Techniques have been developed to produce nanotubes in sizeable quantities, including arc discharge, laser ablation, high pressure carbon monoxide (HiPCO),andchemicalvapor deposition (CVD).Mostof these processes take place in vacuum or with process gases. CVD growth of CNTs can occur in vacuum or at atmospheric pressure. Large quantities of nanotubes can be synthesized by these methods; advances incatalysis and continuous growthprocessesare making CNTs more commercially viable.

1. Mechanical Properties of Nanomaterials

Scientific challenges in nanoscience and nanotechnology include the development of nanomaterials with novel mechanical properties. The need for scratch, mar and/or abrasion resistance is well established in various markets, including fingernail polishes, flooring, plastic glazing, headlamp covers and other automotive parts, transportation windows and optical lenses, where clear scratch-resistant coatings are used. Because the nanosize, many of their mechanical properties of the materials is modified, among others, hardness and elastic modulus, fracture toughness, scratch resistance, fatigue strength, and hardness. Energy dissipation, mechanical coupling within arrays of components, and mechanical nonlinearities are influenced by structuring components at the nanometer scale. This includes also the interpretation of unusual mechanical behavior (e.g., strengths approaching the theoretical limit) and the exploration of new ways to integrate diverse classes of mechanically functional materials on the nano-size.

Strength

Carbon nanotubes are the strongest and stiffest materials yet discovered in terms of tensile strength and elastic modulus respectively. This strength results from the covalent sp² bonds formed between the individual carbon atoms. In 2000, a multi-walled carbon nanotube was tested to have a tensile strength of 63 gigapascals (GPa). (This, for illustration, translates into the ability to endure tension of 6300 kg on a cable with cross-section of 1 mm².) Since carbon nanotubes have a low density for a solid of 1.3 to 1.4 g·cm”³, its specific strength of up to 48,000 kN·m·kg”¹ is the best of known materials, compared to high-carbon steel’s 154 kN·m·kg”¹. Under excessive tensile strain, the tubes will undergo plastic deformation, which means the deformation is permanent. This deformation begins at strains of approximately 5% and can increase the maximum strain the tubes undergo before fracture by releasing strain energy.

Nanoparticle characterization is necessary to establish understanding and control of nanoparticle synthesis and applications. Characterization is done by using a variety of different techniques, mainly drawn from materials science. Common techniques are electron microscopy (TEM, SEM), atomic force microscopy (AFM), dynamic light scattering (DLS), x-ray photoelectron spectroscopy (XPS), powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF),ultraviolet-visible spectroscopy and dual polarisation interferometry.

Whilst the theory has been known for over a century (see Robert Brown), the technologyfor Nanoparticle trackinganalysis (NTA) allows direct tracking of the Brownian motion and thismethodtherefore allows the sizing of individual nanoparticles in solution.

X-ray scattering techniquesarea family of non-destructive analytical techniques which reveal information about the crystallographic structure, chemical composition, and physical properties of materials and thin films. These techniques are based on observing the scattered intensity of an X-ray beam hitting a sample as a function of incident and scattered angle, polarization, and wavelength or energy.