Preface   On a global scale, land resources are becoming increasingly scarce. The quality of resources such as soil, water, plants and animals is also deteriorating. This loss in acreage threatens agricultural production and subsequently future global food security. Ensuring food security requires a multifaceted and multidisciplinary approach. Indian sub-continent assumes significant importance as climatic, ecological, and financial conditions need to be considered in the framework of sustainability. In addition, technological issues like inadequate infrastructural development, poor delivery of extension services and unorganized dissemination of market information make the task of achieving food security more difficult. Major socio-economic issues include low income, food insecurity; support services for nomadic pastoralists, out-migration and farm labour scarcity, poor literacy, low levels of livestock production, shortage of land and fodder, lack of credit and poor quality of agriculture inputs, inadequate markets for bumper harvests, large number of intermediaries in the market, poor infrastructure, limited participation of women in decision-making. Non-existence of policies and guidelines for marginal farmers, lack of prioritization and effective implementation for R&D, need for empowerment of farmers and protection of their interests are the policy issues. The book entitled “Agroforestry for Increased Production and Livelihood Security” would help in understanding the issues and options for small and marginal land holders and ensuring their livelihood through agroforestry. The contributors of the manuscripts have vast working experience in different aspects of agroforestry and from different agro-ecological situations ranging from North -Western Himalayas to eastern region, Indo-Gangetic plains, arid and semi-arid parts, costal and the Deccan Plateau. This compilation would be a ready reference and perfect guide to all those in the profession of teaching agroforestry, environmentalists, policy planners, students and the farmers in general. This book can be used as supplementary reading material in graduate and post graduate courses of forestry, agroforestry and allied biological sciences. This voluminous compilation is likely to boost the cause of development and promotion of usage of agroforestry and encouraging the farmers to take up agroforestry as a sound land use to earn their livelihood. We feel pleased to have compiled the information on agroforestry systems/practices and case studies in different agro-climatic regions of the Indian sub-continent and issues related to promotion of agroforestry. Reader’s views and suggestions on this edition are highly appreciable and would be a guiding force for future pursuits and improvement of subsequent editions.

INTRODUCTION Over the past two decades climate change has evolved from a debate about whether the planet is really warming to an increased focus on how to mitigate and adapt to its impacts. After an extensive review of the available literature on evidence of climate change, the Working Group I to the Fourth Assessment Report of the IPCC, 2007 concluded that “the warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average temperature”. “The scientific evidence is now overwhelming; climate change presents very serious global risks, and it demands an urgent global response” (Stern 2007).

INTRODUCTION The North-Eastern Himalayas comprise of eastern-Nepal, entire Bhutan, parts of North Bengal and the eight states of North-East India viz. Arunachal Pradesh, Assam, Meghalaya, Mizoram, Nagaland, Manipur, Sikkim and Tripura. The region is characterised by diverse agro-climatic and geographical situations. This has a predominantly humid sub-tropical climate with hot, humid summers, severe monsoons and mild winters. The total forest covering this part of India is 17.50 m ha (which includes 8 NE states and hills of West Bengal) which is about 65.94 per cent of the total geographical area (FSI 2013), and the rest either under crops or non-agricultural uses or un-cultivated land. The low area under agricultural crops is due to natural corollary of the physiographic features of the region, as major chunk of the land has more than 15 per cent slope, undulating topography, highly eroded and degraded soils, and inaccessible terrain. Continuous depletion of the forest cover in the region due to shifting cultivation, firewood, and timber collection is posing the most crucial problem resulting in poor soil health and the resultant environmental degradation. In order to overcome these problems the farmers of the Eastern Himalaya have evolved various types of crop rotations in consonance with the varied environmental conditions and agronomic requirements with tradition by practising different approaches since ages. These practices so developed through major and minor adjustments in land use strategies are mostly sustainable from ecological point of view (Dash and Mishra 2001).  The practises of agroforestry in this region exhibit a great deal of variation in crop diversity which is influenced by the crop composition and crop rotation. Along an altitudinal gradient, diversity in agroforestry practices is influenced by variation in ecological factors and difference in agricultural practices. Agroforestry has the potential to improve livelihood as it offers multiple alternatives and opportunities to farmers to improve farm production and income and also provides productive and protective (biological diversity, healthy ecosystems, protection of soil and water resources, terrestrial carbon storage) forest functions to the ecosystems. It is accepted as the sustainable management system that encompasses the variety and variability of animals, plants and micro-organisms which can be combined together to derive key functions of the agro-ecosystem, its structure and processes for, and in support of food production and food security. It is promoted widely as a sustainability-enhancing practice that combines the best attributes of forestry and agriculture. This practice is now recognized widely as an applied science and is instrumental in assuring food security, reducing poverty and enhancing ecosystem resilience at the scale of thousands of smallholder farmers in the tropics (Sharma et al. 2007). Therefore, strengthening linkages between knowledge systems using “Community” participatory management approaches is now seen as critical for sustainable forestry and agroforestry systems (Adhikari et al. 2007; Dhakal et al. 2007; Ramakrishnan 2007).  The mountain communities of eastern Himalayan regions have also adopted diverse agroforestry systems as their land use. Environmental, biological, socio-cultural and economic variation existing in the eastern Himalayas have led to the evolution of diverse and unique traditional agro-ecosystems, crop species and livestock, which facilitate the traditional mountain farming societies to sustain themselves. Appropriate agroforestry systems have the potential to check soil erosion, maintain soil organic matter and physical characteristics, augment nitrogen build-up through nitrogen fixing trees and promote efficient nutrient cycling (Patiram et al. 2003).These systems have today become an established approach of integrated land management system not only for renewable resource production but also for ecological consideration (Saha et al. 2012).

INTRODUCTION Agroforestry has long tradition since dawn of the civilization. Farmers and/or land owners integrate different woody perennials in their cropping system along with the animal unit depending upon the physiographic and climatic conditions. It is well proven fact that such adopted systems/practices are location specific and information on such systems is very limited. Therefore, the benefits accrued from such systems are underexploited in comparison to its potential. With depletion of agricultural lands due to shift in rainfall pattern, landslide, run off, regular leaching of nutrients, drying up of natural springs and lack of irrigation facilities have resulted into uneconomical agriculture in the mountain regions of India in general and particular in Jammu & Kashmir. Most of the villages in mountains witness migration on a large scale and lands turning up barren and un-productive. The agroforestry system can provide a viable solution for such problems.

INTRODUCTION Rajasthan is the largest state of the country with a geographical area of 342,239 Km2 which constituents 10.41% area of the country. The state can be divided into four major regions; the Western desert with barren hills, level rocky and sandy plains; the Aravalli hills running south west to north-east; eastern plains with rich alluvial soils; and south-eastern plateau. The state has varied climate from semi -arid to arid. The average rainfall in the state ranges from 480 mm to 750 mm, being as low as 150 mm in arid region and 1000 mm in south-eastern plateau (FSI 2009). The recorded forest area is 32,639 Km2 which is 9.54 % of the state’s geographical area. The maximum forests are found in the Districts of Alwar, Banswara, Baran,, Bundi, Chittorgarh, Dhaulpur, Dungarpur, Jhalawar, Kota, Rajasamand, Swaimadhopur, Sirohi and Udaipur. The hot arid and semi-arid regions in the country accounts for 20 % of the country’s geographical area spread over seven states namely Rajasthan, Gujarat, Andhra Pradesh, Punjab, Haryana, Karnataka and Maharashtra. It comes nearly 31.63 m ha out of which 19.61 m ha alone is in the states of Rajasthan (62.00 % of total arid region). This area is characterized by low erratic rainfall, high temperature and wind velocity, coarse textured soils with low organic carbon and soil fertility status and poor water holding capacity. The underground irrigation water is limited and highly saline in most of the cases (Chandra 2005). Mono-cropping is a gamble in arid tract of Rajasthan due to low and erratic rainfall and frequent occurrence of drought during crop growth period leading to complete crop failure. To avoid complete crop failure the farmers are adopting mixed cropping system from very ancient time. But the system is not perfect during the adverse climatic situation due to low yield, long duration of traditional varieties and unmatched crop combinations. Therefore, in mixed or multi cropping system, the choice of drought hardy, short duration varieties of crops are necessary to ensure the production of crops even under adverse situations. It has been seen that drought occurrence during month of July and August leads to 67-100 percent decrease in production of pearlmillet and short duration pulses which are the main crops of the region grown under rainfed condition. The people in arid regions of India, since time immemorial has developed location specific agroforestry systems. The scattered trees /shrubs in the agricultural fields are common features of the landscape. Since the beginning of cultivation the farmers deliberately allowed the trees/shrubs to grow with crops. These trees provided them insurance during drought years and provided fodder, fruits, vegetables, timber, fuel, fiber etc. during lean period.

INTRODUCTION India is endowed with a rich and vast diversity of natural resources. However, increasing demographic pressure, unscientific use of soil and water, rapid industrialization and urbanization are leading to over exploitation of the resources. Prime agriculture lands are being diverted for non-agriculture use. The per capita availability of cultivated land has declined over the years from 0.53 ha in 1950 to 0.32 ha in 2001 and is expected to further reduce to 0.23 ha by 2025 and to 0.09 ha by 2050 (GOI 2011). Owing to population pressure the consumption of fuel-wood and fodder in the country is much higher than what can be sustainably removed from forests. In India, nearly 86 million tonnes of fuelwood is being removed from the forests and plantations every year in excess of what they are capable of producing on sustained basis (Planning Commission 2001). Our rich and bountiful biological diversity is also showing signs of erosion which is affecting the livelihoods of millions of people who are directly or indirectly dependent on it. Further, water is mostly treated as a free commodity in the country which is leading to its unsustainable exploitation. Erosion due to wind and water is also leading to depletion of natural resources. About 5334 m tones of soil is lost (16 t ha-1) due to wind and water erosion annually which is highest in black soils (24-112 t ha-1) followed by Shiwaliks (80 t ha-1) and shifting cultivation (27-40 t ha-1) (Mandal et al. 2008). It is now widely accepted that future of food, livelihood and environmental security depends upon the attention paid to conservation, sustainable development and management of natural resources. Corrective measures are immediately required to check the damage caused to the resource base and environment.  Traditionally, trees and crops were grown in association with each other on farm lands. The reason was to get multiple outputs from same piece of land, though such systems were exclusively meant for sustenance with little or no commercial intent. As the population increased there was a need to produce more food and hence slowly the tree component vanished from the farmlands and monocropping became dominant. Over a period of time, due to monocropping, soil degradation had been observed. The need of the hour is to accept the trees as an integral part of the farming system to revert soil degradation and erosion and also to reduce the dependence of external inputs in form of fertilizers, pesticides etc. in the production system. Of late, incorporating trees on the farm lands has been given impetus to get multiple products (fodder, fuel, timber, fiber and fruits) on one hand and resource conservation (soil, water and environment) on the other. Different agencies (institutes, universities and NGO’s) are working on developing region specific agroforestry models to derive maximum advantage of production and conservation from every unit of land. Agroforestry is capable of yielding both wood and food besides conserving and rehabilitating ecosystems. Agroforestry generates high income and minimises risks through efficient utilization of available resources and is thus considered   a potential technology for commercial and protective farming. The extent of the area under agroforestry is not very clear. Trees outside forests in India is estimated between 14,224 million (Ravindranath and Hall 1995) and 24,602 million (Prasad et al. 2000) which is spread over an equivalent area of 17 million ha (GOI 1999) supplying 49% of the 201 million tonnes of fuelwood and 48% of the 64 million m3 of timber consumed annually by the country (Rai and Chakrabarti 2001). Dhyani et al. (2006) reported 7.45 million ha under agroforestry.  As per one of the estimates, about 27.52 million ha is under various types of tree plantations, which include agroforestry, social forestry, farm forestry and others (Table 1). The task force on Greening India (Planning Commission 2001) has identified a potential of 10 millions ha in irrigated lands and another 18 million ha in rainfed areas that could be developed through agroforestry on watershed basis.  The present chapter focuses on the advantage of integrating trees on the farm lands in form of agroforestry for natural resource management.

INTRODUCTION Agroforestry is a land use option that increase livelihood security and reduce vulnerability to climate and environmental change. Agro-forestry has many potential, such as to enhance the overall (biomass) productivity, soil fertility improvement, soil conservation, nutrient cycling, micro-climate improvement, carbon sequestration, bio drainage, bio- energy and biofuel etc. There are many agroforestry systems practiced in India from time immemorial, but the potential of home gardens and their socio-economic significance is very well documented.   Home gardens represent land use systems involving deliberate management of multipurpose trees and shrubs in intimate association with annual and perennial agricultural crops  and livestock within the compounds of individual houses (Fernandes and Nair 1986). Home gardens can also be called as Multitier system or Multitier cropping. Home gardens are highly productive, sustainable and very practicable. Food production is primary function of most home gardens on sustenance basis.

INTRODUCTION Promoting agroforestry is a major opportunity to deal with problems related to land-use and CO2-induced global warming (Albrecht and Kandji 2003). As per recent projections, the area of the world under agroforestry will increase substantially in the near future. Undoubtedly, this will have a great impact on the flux and long-term storage of carbon in the terrestrial biosphere (Dixon 1995). Several studies have shown that inclusion of trees in the agricultural landscapes often improves the productivity of systems while providing opportunities to create carbon sinks (Winjum et al. 1992; Dixon et al. 1993; Krankina and Dixon 1994; Dixon 1995). The amount of carbon sequestered largely depends on the structure and function of agroforestry systems - which to a great extent, are determined by environmental and socio-economic factors. Other factors influencing carbon storage in agroforestry systems include tree species and management system. The significance of agroforestry with regards to carbon sequestration and other CO2 mitigating effects is being widely recognized. There are sound reasons to believe that agroforestry can contribute significantly to carbon sequestration. It is important that research attention is focused on this aspect of agroforestry systems (Nair and Nair 2002).

INTRODUCTION The ultimate objective of forest tree breeding is to develop fast growing high yielding genetically improved superior strains in order to replace the wild natural forest stands so as to obtain higher forest productivity per unit area and time. A breeding programme, in fact, involves purposeful management of genetic variability present in a taxon. The variation is regulated through controlled mating. This obviously, needs detailed information on the nature and extent of genetic variation on one hand and equally on the reproductive biology of the species. A clear understanding of phenological behaviour, time of anthesis, time and duration of stigma receptivity, fertilization, mode of pollination, seed development etc. is necessary for attempting crosses between genetically different forms which is invariably involved in the breeding programmes. Although, tree breeding work has been done to a great extent on the temperate species (Devey et al. 2002; Murat et al. 2006; Gotzenberger et al. 2007), no serious efforts were made in the past on tropical forest species including Jatropha (Jatropha curcas), presumably due to the consideration that similar breeding methods may perhaps, be applied to the tropical trees as well. This, however, is not applicable, as the phenological and reproductive features are typical different to each species. It was in this background that the present research article was planned to collect information on floral biology, breeding behaviour and hybridization programme in Jatropha for subsequent application in its genetic improvement.

INTRODUCTION Total forest cover in India is 70.17 million ha or 21.34% of the total geographical area according to the State of Forest Report 2015. Of this, 8.59 million ha (2.61%) is very dense forest, 31.54 million ha (9.59%) is moderately dense and rest of 30.04 million ha (9.14%) is open. The trees outside forest (TOF) are estimated to cover 9.26 million ha area which constitutes about 2.82% of the total geographical area of the country.  Thus the total forest and tree cover of the country is 24.16% of the total geographical area. The estimates of total growing stock of forest and TOF are 4.195 billion m3 and 1.573 billion m3, respectively. The total growing stock of wood in the county is estimated to be at 5.678 billion m3 which implies an average growing stock of 72.63 m3 ha-1 in 79.42 million ha of forest and tree cover (FSI 2016).

INTRODUCTION Medicinal and aromatic plants (MAPs) play a critical role in the healthcare provision of much of the world’s population, whether they are used to make a decoction in rural Africa, to extract an alkaloid in Switzerland or as a health food supplement in the United States. MAPs are important from several perspectives like preventive and curative treatments and are source of income to underprivileged or aboriginal people who collect these herbal plants from forests or cultivate on their field. The importance and value of traditional and indigenous herbal medicine was the subject of WHO’s campaign during the 70’s, which led to an appeal to all member countries to do their utmost to preserve their national heritage in the form of ethno-medicine and ethno-pharmacology and to re-include the use of known and tested medicinal plants and derivatives into their primary health care in rural areas, as well as an alternative when modern medicine is not available.  Out of more than 400 plants species used for production of medicine by the Indian herbal industry, fewer than 20 species are currently under cultivation in different parts of the country (Uniyal et al. 2000). According to the Department of Ayurveda, Yoga and Naturopathy, Unani, Siddha and Homoepathy (AYUSH), India has 5,662 varieties of medicinal plants and of these trading takes place in 460, while 178 are exported in huge quantities (over 100 metric tonnes per year) and about 70 per cent of India’s population use traditional medicines derived from numerous plant species (Niraj et al. 2002; Saigal et al. 2002). It is estimated that in developing countries, about 90 per cent of medicinal and aromatic plants are harvested from wild while cultivated lands account only for 10 per cent of the total medicinal plants in active trade (Karki 2002). The increasing demand calls for cultivation of these valuable healers on commercial basis. However, the available land cannot be brought directly under MAPs cultivation. There is need to identify the landuse systems, already in practice, which may provide condition congenial for better growth and development of medicinal and aromatic plants as they are naturally getting in the wild. Tree plantations, fruit orchards and home gardens seems to be the viable option for commercial cultivation. Out of these fruit orchards could be more potential land use. Fruit trees have long gestation period of 8-10 years and till canopy development, the interspaces can be conveniently used for cultivation of medicinal and aromatic crops to get additional income. Even at later stages of orchard development trees have minimal adverse affect on the growth and yields of a number of medicinal plants grown as intercrops compared to the yields in the open (Nair et al. 1989), in some instances there may be reduction of yield of MAPs and fruit component, but the combined returns from both the components are greater than from sole cultivation. This temporal scale is even more in case of shade loving medicinal and aromatic plants. Peasants prefer fruit trees on their farms (Raintree 1992; Franzel et al. 1996) with perspective of contribution to consumption (Salam et al. 2000) and income generation (Ayuk et al. 1999; Delobel et al. 1991). Thus, these components are well thought-out to be beneficial due to low labour input and comparatively high returns round the year. This chapter presents a brief review of growth, yield and economic viability of such tree-crop combinations and further explore their potential under fruit tree based horti-medicinal agroforestry systems.

INTRODUCTION Nearly 60% of the population of the country is dependent on agriculture. Rainfed agriculture supports 40% of the population and 75% of the poorest of the poor in the country (Pant 2001). Therefore, maintenance of health of production base stands as a prime goal to be achieved for sustainable production, prosperity and posterity. Tree culture is highly necessitated for amelioration of climate, soil, production of firewood, fodder, timber, fibre, fruit, gum etc. Hence, agroforestry is a viable option particularly in the Indian context.

INTRODUCTION Wood has been a source of fuel from time immemorial for human societies. It has been used directly as firewood and also as charcoal. The world today is energy deficient. Energy derived from fossil fuels is costly, unsustainable and its extensive use is polluting the environment. The much talked about phenomenon of ‘Global Warming’ has been ascribed to the higher accumulation of greenhouse gasses in the atmosphere released from the use of fossil fuels and also deforestation. Wood biomass is one of a range of renewable energy resources. It has an advantage over wind and solar energy, for example, as these cannot necessarily deliver power when required. Wood besides being renewable is also a clean and carbon-lean fuel and could play a valuable role in our contribution to climate change mitigation.

INTRODUCTION Climate change is one of the most important global environmental challenges facing humanity with implications for food production, natural ecosystems, freshwater supply, health, habitat destruction biodiversity, etc. According to the latest scientific assessment, the earth’s climate system has demonstrably changed on both global and regional scales since the pre-industrial era. Since the very beginning of civilization, land resources have been under tremendous pressure for food and forest products. Anthropogenic activities have affected the biosphere through changes in the landuse and forest management activities, thus altering the natural balance of greenhouse gases in the atmosphere. The environmental security thus, has become a serious concern across the globe. The meteorological records have shown significant increase in the environmental temperature referred to as the global warming. Human activities have increased green house gases and raised global temperature by 0.50 C over the past 100 yr, which may increase by 1.4 to 5.8°C during the next century (Bhadwal and Singh 2002). Evidence of this global crisis include the rise in global sea levels by 3.4 mm yr-1 ((http://climate. nasa.gov/vital-signs/sea-level/) through the melting of the world’s snow peaks and glaciers, which poses a threat to millions living in coastal areas. A drastic effect on splitting of huge glacier in the Antarctica has already been registered, which has thrown a challenge to save the earth, lest the very survival of the mankind will be jeopardized. Each degree rise in temperature will displace the limits of tolerance of land species some 125 km towards the poles or 150 m vertically on mountains. The Inter-governmental Panel on Climate Change (IPCC) estimates that 20 to 30 per cent of plants and animals could be at risk of extinction if average global temperatures reach the projected levels (Hawkes et al., 2000).

INTRODUCTION Carbon dioxide gas is fundamental to sustaining life on earth for two reasons (i) it is a source of C for photosynthesis, and (ii) it acts like blanket in atmosphere that keeps the earth warm. Molecular CO2 absorbs short wave solar radiations and release them as long wave infra red radiations. An atmospheric concentration of 300 ppm is adequate to support life on earth. CO2 accounts for about half of the greenhouse effect. The natural concentration of green house gases (GHGs) has been essential to life on earth, creating the average temperature of 15ºC. Without the naturally occurring green house effect, the average temperature would be minus 18ºC. CO2 concentration has now reached 400 ppm. If present trends continue then CO2 levels would reach 600 ppm in 2100 and 1300 ppm in 2200 and level off at 1800 ppm in the year 2400 (Harvey and Danney, 2000). With increasing CO2 concentration the amount of solar radiation absorbed by atmosphere would increase and make earth warmer. The higher atmospheric temperature can affect global hydrological cycle and alter the distribution and productivity of terrestrial biota. This can have devastating consequences for human life as each 10C increase in temperature, vegetation zones may change dramatically, moving toward the poles by 200-300 km. Further, each 1ºC of global warming will also increase water evaporation, leading to about 2% greater mean global precipitation.

INTRODUCTION Himachal Pradesh, the mountainous state is well known for its natural wealth. It is situated between 300 22’ 40"to 330 12’ 40" N latitude and 750 45’ 55" to 790 04’ 20" E longitude in the western Himalayas. The 12 districts viz., Bilaspur, Chamba, Hamirpur, Kangra, Kinnaur, Kullu, Lahaul & Spiti, Mandi, Sirmaur, Shimla, Solan, and Una of the state covered 10.5 per cent of the Indian Himalayan Region (IHR) and 1.69 per cent of country’s geographic area. State experienced high variation in an elevation and climatic conditions. An elevation of the stateranged from 350 to 6975 metres above mean sea level (amsl.) that increases from west to east and south to north.On the basis of elevation and slope,the state is divided into fourdistinct topographical regions: (1) Shiwalik Hills, (2) Mountains-Lesser Himalaya, Greater Himalaya and Trans Himalaya, (3) Valleys-Shiwalik dun valleys, fluvial, and glacio-fluvial valleys, and (4) Mountain Passes (Singh and Kumar, 2014). Whereas, physiographically, state is divided into four agro-ecological zones: the Shivaliks’ low, mid and high-hills; and the cold and dry or the alpine zone (Table 1). The 70% of the state area is steep to very steep, about 19% is moderate to moderately steep, and 11% is gentle to nearly level slopes.

INTRODUCTION Soil is known to harbour an array of micro-organisms. The soil micro-organisms play vital roles in the half-hidden portion of the plant i.e., the rhizosphere, where they are invariably present and are stimulated by organic substrates supplied by the plant. These are known to form the mutualistic, symbiosis with photosynthetic plants and play a key role in increasing availability of plant nutrients, the improvement of their uptake, the production of plant growth regulators, plant protection against root pathogens etc. in both natural and man-modified eco-systems.

INTRODUCTION Phytotoxin literally means “plant poison”; it may refer to any toxin produced by a plant. Phytotoxins generally have allelopathic effect. Allelo-chemicals when added/released to substratum may be directly or indirectly harmful or beneficial to the growth and development of the associated vegetation or to the source plant itself. The definition of allelopathy accepted by the International Allelopathic Society is; “any process involving secondary metabolites produced by plants, algae, bacteria and fungi that influence the growth and development of agricultural and biological systems” (Torres et al. 1996). Allelo-chemicals are defined as bio-communicators suggesting the possibility of active mixtures, because of the findings in which single compounds are not active or are not as active as a mixture (Macias et al. 1998). 

INTRODUCTION The interactions of plant communities – natural or man-made, with their pests are invariably complex, and the complexity further increases with the diversity of the system. When a farmer adopts agroforestry instead of monocultures, the opportunities of relatively easy monitoring of the pest and their frequent disturbance through crop rotation, tillage and burning are traded against a greater stability of the system with an increased potential for self-regulation, which is however complex and more difficult to control. For this trade to be successful in reducing pest risks, agroforesters should not merely rely on increased diversity, but should attempt to integrate into their decisions the full range of traditional and scientific knowledge on the interactions between plant species, planting designs and management practices on one hand, and pests and their natural enemies on the other hand. This obviously requires collecting knowledge and organizing in more systematic way than up to now.

INTRODUCTION The terms agro-forestry and farm forestry are used interchangeably in India with respect to the establishment and/or management of trees on farms for productive purposes. It also particularly recognizes the use of trees and shrubs on farms to support agricultural production, protect soil and water resources, enhance biodiversity, sequester carbon, and improve landscape values. Lundgren (1982) defined “Agroforestry as a collective name for land use systems and technologies where woody perennials are deliber-ately used on the same land unit as agricultural crops and/or animals, either in some form of spatial arrangement or temporal sequence. In agroforestry systems there are both economical and ecological interactions between the different components”. It has been proposed that including a tree component within the farming system, either on bunds and boundaries (sequentially with crops) or intercropped in an agroforestry type configuration, can lead to increased land productivity while diversifying the farming enterprise (Atta-Krah et al. 2004; Huxley 1999; Young 1989), and increase economic security for small farmers (Russell and Franzel 2004).

INTRODUCTION The entire Himalayan region is vast and its diverse geographical grouping is unique and has complex ecosystem and occupies about 18% of the total geographical area of India. Indian Himalaya (27O 50' – 37O 06' N and 72O 30' – 97O 25' E) includes the parts of trans, north-west, west, central and east Himalaya and covers approximately an area of 4,19,873 Km2 with 2500 Km length and 240 Km width. The north-western Himalayas generally represent the Himalayan tract from Kumaon in Uttar Pradesh to Chitral in Gilgit. The Himalayan ranges situated in this region exhibit a diverse climate, topography, vegetation, ecology and land use pattern. The annual average rainfall varies from 8 cm in Ladakh to over 200 cm in some parts of Himachal Pradesh and Uttar Pradesh. The vegetation may vary from the scrub in the lower hills to arctic in the Greater Himalayas. The unique physiography, climatic conditions and soil characteristics of the area has resulted in a variety of habitats and a significant biological and cultural diversity. Along the altitudinal gradient (300-800 m.a.s.l) the vegetation varies from sub-tropical, temperate, sub-alpine to alpine types. It supports about 8000 species (47.06% of the total flowering plants of India) of which 30% are endemics, 10.2% trees, 8.44% wild edibles and over 15% medicinal (Samant and Dhar 1997).

Introduction Biodiversity provides enormous direct economic benefits, an array of indirect essential services through natural ecosystems, and plays a prominent role in modulating ecosystem function and stability. It provide farming systems and taxa the means to recycle nutrient, reduce insect, pest and disease problems, control weed, maintain good water and soil conditions, handle climate stresses while producing commodities necessary for human survival. It is estimated that 1400 m ha of croplands and agro-ecosystem may provide ecosystem services worth US$ 92 ha-1 per year in pollination, biological control, and food production amounting to total US $ 128 x 109 per year (Costanza 1997). Moreover, Thrupp (1997) explained several benefits provided through conservation of biodiversity (Figure 1). The animal and plant diversity and the knowledge of associated management of these resources are the assets with the farmers which are important in marginal and difficult farm conditions. Higher diversity allows greater access to available resources, and hence increased net primary production and decreased nutrient losses. Diversity management can constitute a central part of livelihood management strategies of farmers and communities in different production system (Rege et al. 2003). The multifunctional services of biodiversity in amelioration of agro-ecosystems as given in Table 1 have also been emphasized by both the Millennium Ecosystem Assessment (2005) and the International Assessment of Agricultural Science and Technology for Development (2008). 

INTRODUCTION Indigenous agroforestry systems exhibit a great intricacy with respect to their components where trees, shrubs, climbers and grasses are common. In the north-western Himalaya, farmers maintain naturally regenerating tree/shrub species, particularly on edges of terraced agriculture fields without any significant input of manpower. These systems are called as indigenous agroforestry system (Ram and Singh 1996; Vishvakarma et al. 1998, Thakur et al. 2004 and 2005). Shrubs have been meeting the fuel wood requirement of the local peasants from forest as well as village wasteland and field boundaries. Shrub dominated ecosystems extend from arctic to tropical region and occur over the entire moisture gradient from desert to wetland (Specth 1979; DI Castro 1981; West 1983). 

INTRODUCTION Biodiversity  refers to varieties of life on the Earth including  animals, plants, microbes and genes within them, their habitats and ecosystems and all variations within a given ecosystem, biome or entire planet. Biodiversity is the basis of life on Earth, important for the functioning of ecosystems, provides us with products and services without which we cannot live. Consider our food range in India. It ranges from Indian bread (chapatti), rice and rice products and related curries and other varieties made out of different vegetables. These food items are made of wheat, paddy, maize, bajra, ragi, potato, tapioca, sweet potato,  yams and corns, pulses like pigeon pea, green and black gram, Bengal gram, soyabean, vegetables like tomato, brinjal, cucumber, pumpkin, drum stick, bitter gourd, snake gourd, bottle gourd and various gourds, French bean, amaranth and  so many leafy  vegetables, spices and condiments like chilly, cardamom, ginger, turmeric, pepper, nutmeg, clove, cinnamon, cumin, coriander, fenugreek etc. This is the diversity of food we have in India. Similarly, all other groups such as herbal medicine, ornamentals, timber and non-timber species are also very diverse.

INTRODUCTION The latest Assessment Report (AR-5) of Intergovernmental Panel on Climate Change (IPCC) has concluded that warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The report further pointed about the warming of atmosphere and ocean; shrinking of glaciers, sea level rise and more frequent and intense extreme weather events. The most critical information pertains to the increase of the concentrations of greenhouse gases. The report figures that human influence, primarily the burning of fossil fuels, has been the “extremely likely” dominant cause of global warming over the past several decades. Based on the scientific evidences, it is reported “warming by the end of the 21st century will lead to high to very high risk of severe, widespread, and irreversible impacts globally” (Edenhofer et al. 2015).

INTRODUCTION   A single teaspoon of soil has more organisms than the total number of people in this planet. Therefore measuring microbial population and their activity in soil is essential in order to measure the potential of a soil to mineralize nutrients. The rhizosphere is the biologically active zone of soil, where plant roots and microorganisms interact, and is of significant importance for plant performance as well as for nutrient cycling and ecosystem functioning (Singh et al. 2004; Marschner et al. 2004., Bhaduri et al. 2015). The structure of rhizosphere microbial communities is the result of complex interactions between plant genotype and fertilization (Aira et al. 2010).

INTRODUCTION Resource, land use patterns and erosion of homrgardens biodiversity have been at the core of the debate on sustainable ecosystem management today. Homegardens are considered as a resource system of multiple functions and an important wheels of vehicle for biodiversity, environmental and ecological benefits, food security (either directly food grains, fruits, vegetables and root crops or indirectly improving soil conditions and there by promoting understory crop productivity especially on degraded sites), soil conservation potential, nutritional security, socio-cultural as well as mitigation of the impact of climate change and job creation in developing and under developed countries. While increasing human population, urbanization and pressure on the earth’s ecosystems, has resulted in the breakdown of these traditional agroforestry systems, accompanied by increasing economic, cultural, nutritional, and environmental problems, there is little awareness that homegardens are under similar threats.