eChapters

Abstract: Alley cropping system is known for several services like fodder and fuel production, nutrient management, and soil erosion control from hilly terrain in humid tropics, but it could not make in farmers field. This study explores the role of Gliricidia leaf manure on nitrogen management in soils. Simultaneously, the system is modified to make it highly profitable, so that it may become farmer’s friendly in humid tropics. For nitrogen management in soil, two methods (leaves being incorporated into soil vs. surface) and three times of application, i.e. zero week after sowing (0 WAS), two week after sowing (2 WAS) and four week after sowing (4 WAS), of Gliricidia leaf in soil was considered. Two additional treatments, urea (120 kg ha-1, equal to the leaves) and control (no urea + no leaves) are also maintained to compute recovery of nitrogen from the leaves by the crop, and to know if the leaf manure could produce grain yield equal to that of equivalent urea. The study reveals there is no effect of the method of application on the decomposition and release of nitrogen from the leaves, soil N mineralization, nitrogen uptake, shoot biomass and yield of the crop, but time of application affects these parameters significantly. Maximum 50 % nitrogen is released quickly from the leaves within 15 days and remaining 48-49 % gradually in 60 days. Rate of soil N mineralization; nitrogen uptake, shoot biomass and grain yield in maize are the highest in 2 WAS and lowest in 4 WAS treatment. Recovery of nitrogen from the leaves is very low ranging from 4.5 to 9.3 kg ha-1. The leaves do not produce yield in maize equal to that of equivalent urea. However, for synchronization of maximum release of N from Gliricidia leaves and it’s 

Abstract: Stall feeding to cattle is not practiced in the Andaman Islands since generations. In the morning, after milking, cattle are allowed to go for free range grazing in the nearby forest or coconut arecanut orchards. But, like mainland territory the cattle do not form herd. They are trained in such a way that come back home during evening where they are fed with concentrate before the milking. Coconut and arecanut orchards occupying more than 14000 ha land are second major land use after forest in the Islands. The forage production in the grazing lands are not sufficient to meet out the demand of huge livestock population particularly during the lean period, form January to April. An attempt has been made to know the effect of four N fertilizer levels (0, 60, 80 and 120 kg ha-1 N) on net soil N mineralization rate (NMR) and soil moisture (SM), and shoot biomass (SB), FP, shoot biomass/root biomass ratio (SB/RB), N concentration in SB, N uptake and nitrogen use efficiency (NUE) of three grasses [Guinea (Panicum maximum Jacq.), Para (Brachiaria mutica (Forssk) Stapf) and Hybrid-napier (Pennisetum purpureum Schumach.)] under three canopy positions [under canopy (UC, representing high shade), between canopy (BC, representing low shade) and open] of coconut trees (Cocos nucifera L.) in a coconut based silvopastoral system in the Island conditions. The study has revealed that the tree reduces light 59% under UC and 32 % under BC positions, but the N fertilizer levels increase NMR by 11 to 51 % under UC and 3 to 44 % under BC positions compared to the open. SM does not differ across the canopy positions

Abstract: The Trans Gangetic Plains of India is a large fertile tract of north-west India where intensive rice-wheat based farming has led to soil and water problems.  Agroforestry is among the viable options to overcome these problems. It has already shown positive effects such as increasing tree cover, augmenting wood needs of industries and ameliorating socio-economic status of farmers. Poplar based agroforestry models have been widely accepted by farmers. Site specific superior poplar clones have been developed for superiority, growth and resistance to pest and diseases. Farmers successfully grow the annual crops (sugarcane, turmeric), seasonal crops in winter (wheat, potato, mustard, mentha etc.) and summer season (cotton, moong, pearl millet, sorghum etc). The reduction in wheat grain yield varied from 10.2 to 46.6 per cent from first to sixth year as compared to open field. Selection of shade tolerant crop variety, appropriate sowing time, irrigation, seed and fertilizer dozes help to mitigate these losses. Wheat sown during first fortnight of November produced significantly higher grain yield than other sowing times. Wheat variety PBW 502 performed better amongst the six wheat varieties tested under poplar. Tree crop interactions influence the damage caused by insects and diseases. Cultural practices reduce the number of hibernating pupae of poplar leaf defoliators (PLD) which subsequently leads to lower incidence of these defoliators. Percent damaged leaves were more in fallow (5.44 - 60.53) and less in intercropped plantation (2.49 - 49.20). PLD adult emergence percentage was significantly less in intercropped and ploughed (49.5 and 67.5) than fallow (83.0) plantations

Abstract: Economy of Bihar is solely dependent on agriculture. Only 7% area is under forest as against a minimum 33% required for ecological balance. 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 some agroforestry systems have been recommended and are discussed in this paper. Economics of some of the successful system has also been discussed. A detailed account of prevalent agroforestry practices in Bihar is also given. Agri-horticulture system is most popular system adopted by large and medium farmers in the region. Finally, constraints in adopting and carrying out research in agroforestry along with future strategies to extend agroforestry in Bihar are also given in the paper.

Introduction

Agroforestry land use system is one of the most important means for improving productivity of rural resources. People’s perception about agroforestry varies with their use perspectives. Only 7 % area is under forest as against a minimum 33 % required for ecological balance. Per capita consumption of wood fuel in Bihar is 0.27 m3 per year and industrial wood is 0.054 m3. One of the studies, on demand and supply of wood in Bihar conducted by Division of Forestry

Abstract: Dry land ecosystems cover about 41% of the earth’s land surface including hyper arid region. There is a considerable difference between them, in which arid region covers 7% of global lands. These are barely productive and provide a meager existence to small populations, usually nomadic with little settlements as in Thar desert. In addition to hyper arid, other types are arid, semi and dry-subhumid, which are in danger of becoming desertified. Environmental conditions are harsh affecting agriculture production. People of Indian arid zone are well acquainted about agroforestry- an age old practice in India, but maintaining only a few trees on farmlands does not serve the growing demand of fodder, fueldwood and food. Adoption of alternate land use systems like alley cropping, lay farming, tree farming, dryland horticulture etc. may intensify crop production and sustain the rural livelihoods. The selection of tree/shrub species may be based on the tolerance towards drought, salitnity/alkalinity prevailing in the region. Based on arrangements and combinations of trees/shrubs with associated crops, agroforestry are categorized into: agri-silviculture, agri-horticulture, agripasture, silvipasture, hortipasture and silviherbal. Common trees are P. cinreraria, T. undulata, Salvadora oleoides, Acacia nilotica, A. tortilis, Ailanthus excelsa, Zizyphus nummularia, Z, mauritiana etc.

Introduction

Agroforestry has vast potential not only to meet the demands of fuel, fodder, timber, medicine and other Non-wood Forest Products but also to enhance green cover, soil and water conservation and reduce pressure on forests. The objective of agroforestry is to take advantage of the complimentary relationships between trees, crops and livestock in such a way that the productivity, stability and sustainability of the total system are maintained. It has great potential in improving degraded and affected sites and has been recognized as a restoration agent, rehabilitation process, and bioremediation mechanism, in addition to increasing farm income.

Agroforestry is not a new practice for the farmers of Tamil Nadu.  It has been in practice in various forms e.g. growing Acacia leucophloea in the grazing lands with Cenchrus ciliaris in the Kangayam tract of Tamil Nadu exists from time immemorial to meet the mixed farming in that tract. In late 60’s farmers in coastal areas of Chengalpattu and Cuddalore districts started growing Casuarina to be sold as firewood.  This effort was entirely of the farmers without any support from the Government.

Abstract: Agro-ecosystem analysis of the island farming system revealed four distinct micro farming situations (MFS) viz., Hilly (MFS I), Slopping hilly upland (MFS II), Medium upland valley (MFS III) and Low lying valley (MFS IV). The enterprise combination study indicated the suitability of plantation based cropping sequences + backyard poultry and livestock in hilly areas, Short and medium duration paddy, vegetables, floriculture, plantations, fodder + backyard poultry + goat,  fish cum poultry cum duck and cattle in slopping hilly uplands, vegetables, plantations + backyard poultry, fish cum poultry cum duck in medium upland valley and long and short duration paddy, vegetables + backyard poultry, fish cum poultry and cattle in low lying valley micro farming situations. Productivity and profitability analysis of different farming systems under various micro farming situations revealed that net return obtained from cropping was Rs 3,26,408,  livestock and poultry was Rs 64,300 in MFS I where as under MFS II, it is Rs. 1,53,989 from cropping, Rs 77,176 from livestock and backyard poultry and Rs 12,465 from poultry + duck + fish. In MFS III, net return obtained from cropping was Rs 9,297 livestock was Rs 72,306 and poultry was Rs. 2,630 and poultry + duck + fish was Rs 24,957. Similarly, in MFS IV, net return obtained from cropping was Rs 57,760 where as Rs 90,893 was obtained from livestock, Rs 11,000 from backyard poultry and Rs 14,872 from poultry

Abstract: The study reports the influence of biophysical and socio-cultural factors on composition, diversity and distribution of plant species in the homegardens of the Andaman and Nicobar archipelago of India. In Nicobar mostly an aboriginal tribe the Nicobari predominates. The Nicobaries are Christians. However, in the Andamans people from different parts of Indian subcontinent have been rehabilitated in the mid twentieth century. Mixed culture prevails in South Andaman, but in the other Andaman islands either Bengali or Tamil culture predominates. Biophysically, South Andaman is hilly whereas Nicobar is flat. Rests of the islands lie in-between the two extremes. But, all are similar climatically. Twelve to thirty-four plant species are found in the homegardens that are planted, cared and harvested. These plants are: palm, fruit, spice and forest trees, formed three-storey structure in Andaman and two-storey structure in Nicobar’s homegardens. Floristic similarity among the homegardens of the Andamans is 82 to 92%. However, it is only 12-18% between the homegardens of Andaman and Nicobar. Compared to Nicobar, species richness is greater in the homegardens of the Andamans. But, diversity is higher and evenness lower in the homegardens of Nicobar. All plant species in the Nicobar’s homegardens are spontaneous in regeneration. Among the Andamans, proportion of spice trees is higher in the homegardens of South Andaman, mango and citrus in North Andaman, and pineapple and vegetables

Abstract: Acacia nilotica (L.) Willd. Ex Del is an important multipurpose tree of traditional agroforestry system in the central India. The present chapter reports influence of tree canopy positions, i.e. mid canopy, canopy edge and canopy gap, of Acacia nilotica (12-yr) on texture, organic C, total and mineral N and P and soil pH, in different depths of soils, on productivity of rice during rainy and wheat during winter season. It also reports how residual nitrogen under the tree influence yield of rice following its felling after completion of rotation cycle. Sand particles are found to decline by 10% and 9% whereas clay particles increase by 14% and 10% under mid canopy and canopy edge, respectively, than in open. Clay particles are not influenced by the canopy positions. Soil organic C, total N, total P, mineral N (NO3- -N and NH4+- N) and P are greater under mid canopy and canopy edge positions than in open. Soil organic C and N pool sizes are maximum in 0-10 cm and decline with depths. Total and mineral P contents are nearly uniform across the depths. C/N ratio increases with soil depth. Despite greater nutrients pools under the tree, density, aboveground biomass, belowground biomass, aboveground biomass / belowground biomass ratio and yield of the rice decline by 27.5%, 27.5%, 19.1%, 14.8% and 24.9%, respectively. Like the rice, yield of wheat also declines under the tree. 

Introduction

Agroforestry refers to practices, which deliberately or intentionally mix or retain woody perennials on the crop/animal production systems. It combines elements of agriculture, crops and/ or animals with elements of forestry in production system in a unit of land, either simultaneously or sequentially. The term woody perennials includes tree, shrubs, bushes, palm, bamboos, etc. which in agroforestry context are often referred to as multipurpose trees and shrubs (Wood, 1988). The word deliberate has significance a few trees remaining during the process of land clearance for agriculture is not agroforestry. To qualify as agroforestry, a system should actively promote the woody perennials for a particular purpose, or purposes, on the farm (Bhatt et al., 2001). This land use system is particularly suitable for resource poor marginal farmers became diverse needs are fulfilled by one system with escape routes during natural calamities. In hill agro-ecosystems, agroforestry plays an important role in sustainable resource conservation and food security. It is also used to diversify and intensify farming systems through integration of indigenous tree-crops.

Abstract: The adoption of agroforestry systems has gained wider attention in the Multilateral Environment Agreements (MEA), international academia and policy makers for their multifunctional role and dynamics of ecosystem services. The Convention on Biological Diversity (CBD) has put forward ecosystem approach while Intergovernmental Panel on Climate Change (IPCC) emphasized agroforestry as an appropriate means to reduce emissions and enhance sinks of green house gases. Traditional agroforestry systems such as cardamom-based and farm-based practices are good examples in the Eastern Himalayas. We analyzed the management diversities and functional roles of these agroforestry systems for their productive and protective functions, biodiversity conservation, carbon sequestration, reduction of run-off rainfall, improvement of soil fertility, nutrient dynamics, nutrient release through decomposition, N2-fixation, energetics and efficiencies. Use of N2-fixing Himalayan alder (Alnus nepalensis) in large cardamom (Amomum subulatum) and Albizia spp. in mandarin agroforestry are traditional innovations. The agroforestry systems and practices are examples of how fragile and steep slopes of the mountains are converted into ecologically resilient productive zones. These adaptive traditional agroforestry provide options for sustainable management of natural resources from a unit land use types to a landscape level land use stages and offer opportunities for socioeconomic benefits.

Abstract: Shifting cultivation locally called Jhuming is a part and parcel of tribal life of the North Eastern Hill Region of India and it has direct bearing with their socio-cultural system. It is a boon to the farmers as long as the jhuming cycle is sufficiently longer (10-15 years) as this would not only produce a good crop but also gives sufficient time for ecological restoration and biophysical balance. However, with the increase in population pressure on land the jhuming cycle is getting drastically reduced (3-6 years). As a result of this, soil health is getting degraded and overall ecosystem is in threat. Many important flora and fauna are in the verge of extinction. As we cannot run away from the problem at least thinking about posterity, we have to find a decisive solution immediately. Developing improved methods of jhum cultivation like proper bunding, residue recycling, use of high yielding varieties etc. are few short term options. However long term viable options would be proper land configuration like terraces, water harvesting, agroforestry, adoption of integrated farming system approach and above all education and awareness among the tribal farmers which would help in sustaining the ecosystem of the region.

Abstract: The size of the homegardens ranged between 0.10-1.00 ha; they were located in tropical region with multi-storied structure, commonly containing three layers but sometimes with four layers. Individual households were the sampling units and for each homegarden, the area was measured and crop composition, species richness and uses of plant species was enumerated through direct observation and interviews with the farmers. The composition and richness of species varied between the homegardens but was related to site characteristics and size of the garden. A total of 231 plant species (105 tree species, 50 shrubs and 76 herbs) belonging to 88 families were recorded from the gardens among which 27% species were common to all gardens. Among the trees, as many as 24 species (23%) were common to all the homegardens. The vegetable species constituted the major functional group followed by fruits. Homegardens were found to be a good reservoir of plant genetic resources that preserve diverse landraces, cultivars, and many more ecologically and economically important plant species. Our study depicts that the homegardens can play an important role in food security and sustainable livelihood support of this hilly people in a variety of ways and can be an alternative to shifting cultivation.

17.1 Introduction

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

16.1 Fuel Cell

Fuel cell is an electrochemical device that convert chemical energy of a reaction directly into electrical energy. The basic physical structure of a fuel cell consists of an electrolyte layer in contact with a porous anode and cathode on either side. A schematic representation of a fuel cell with the reactant or product gases and the ion conduction flow directions through the cell is shown in Fig. 16.1

15.1 Introduction

The oceans cover 71% of the earth’s surface and it acts a natural collector and store of solar energy. On an average day, 60 million sq. km. of tropical seas absorb an amount of solar radiation equivalent in heat content to about 245 billion barrels of oil, if this energy could be trapped, large scale renewable source becomes available especially for tropical countries. The energy available in the ocean is clean, continuous throughout the year and renewable.

Renewable energy contribution to the available energy resources is very important to the country as it is presently facing an energy resources crunch. Out of the total installed capacity of approximately 370.106 GW as on March 2020, Renewable Power Plants including hydro-electric plant contribute 35.86 % of total installed capacity. However, with the present increase in demand, more attention is required to extract the renewable sources so that at least 50 to 60 % share for the total energy requirement by the renewable energy sources.

There are various forms of ocean energy such as Ocean Thermal Energy Conversion (OTEC), Wave Energy, Tidal Energy, Salinity Gradient Energy, Offshore Wind Energy, Marine Currents, Marine Biomass Conversion. Among these, the first three forms are likely to be technically viable for the future.

More recently Ministry of New and Renewable Energy (MNRE), Government of India hasdeclared Ocean Energy as renewable energy, and clarified to all the stakeholders that energy produced using various forms of ocean energy such as tidal, wave, ocean thermal energy conversion among others shall be considered as renewable energy.

MNRE reported that, the total identified potential of tidal energy is about 8000 - 9000 MW, with about 7000 MW in the Gulf of Cambay in Gujarat, about 1200 MW in Gulf of Kutch and less than 100 MW in Sundarbans. Primary estimates of wave energy potential along Indian coast are about 5 – 15 MW/m, so that theoretical estimates are around 40 – 60 GW. Ocean Thermal Energy Conversion (OTEC) has a theoretical potential of 180,000 MW in India subject to suitable technological evolution. As of date, there is not any installed Ocean Energy capacity in India.

14.1 Introduction

Hydro-electric power is electricity produced by the movement of fresh water from rivers and lakes. Gravity causes water to flow downwards and this downward motion of water contains kinetic energy, that can be converted into mechanical energy, and then from mechanical energy into electrical energy in hydro-electric power stations. (“Hydro” comes from the Greek word hydra, meaning water). At a good site hydro-electricity can generate very cost-effective electricity.

13.1 Introduction

Geothermal energy is the nature-based heat generated from within the earth. Underneath the earth’s relatively thin crust, temperature range from 1000 to 4000°C & in some areas, pressures exceed 138 MPa is available. Geothermal energy is most likely generated from radioactive thorium, potassium and uranium dispersed evenly throughout the earth’s interior which produce heat as part of the decaying process. This process generates enough heating, keep the core of the earth at temperature approaching 400°C. Composed primarily of molten nickel & iron, the core is thought to be surrounded by a layer of molten rock, the mantle at approximately 100°C. Nine major crustal plates float on the mantle & currents in the mantle cause the plates to drift, colliding in some areas and diverting in others. When two continental plates converge a complex series of chemicals in the form of molten magna rises in the earth’s crust and depending upon its magnitude, it may break the crust and reach at the earth surface. Volcano, hot spring, geysers & fumaroles are natural geothermal resources near the surface and perhaps where economic drilling operations can tap their heat and pressure.

12.1 General

The term “biomass” generally refers to renewable organic matter generated by plants through photosynthesis. Materials having organic combustible matter is also referred under biomass. Biomass is an important fuel source in our overall energy scenario. Biomass is produced through chemical storage of solar energy in plants and other organic matter as a result of photosynthesis. During this process conversion of solar energy in sugar and starch, which are energy rich compounds takes place. The chemical reaction of photosynthesis can be written as:

6CO₂ + 6H₂ O + sun light → C₆ H₁₂ O₆ + 6O₂ + 636_kcal

It indicates that the storage of 636 kcal is associated with the transfer of 72 gm carbon into organic matter. Biomass can be directly utilized as fuel or can be converted through different routes into useful forms of fuel. In fact, biomass is a source of five useful agents, which start with `F’ like Food, Fodder, Fuel, Fiber and Fertilizer. Further, biomass has many advantages like.

11.1 General

Biogas is generated through a process of anaerobic digestion of organic materials. The materials normally used are human and animal waste, crop residues, agro-industrial waste and other biomass in a combination with water. Biogas production technology contributes in following ways:

(a)It provides a better and cheaper fuel for cooking, lighting and for power generation.

(b)It produces good quality, enriched manure to improve soil fertility.

(c)It provides and effective and convenient ways for sanitary disposal of human excreta, improving the hygienic conditions.

(d)It generates social benefits such as reducing burden on forest for meeting cooking fuel by cutting of tree for fuelwood, reduction in the drudgery of women and children etc.

(e)As a smokeless domestic fuel, it reduces the incidence of eye and lung disease.

(f)It also helps in generation of productive employment.

The biogas technology is primarily based on fermentation of cellulosic rich organic matter under anaerobic conditions. The methane producing bacteria become more active after the creation of anaerobic conditions, thus, the gas produced become rich in methane & carbon dioxide, beside traces of hydrogen sulphide, ammonia, oxygen, water vapour etc. depending on the feed material and other conditions. For burning of gas, it is necessary that methane contents should be more than 50 per cent. The complete knowledge of process of methane production including its chemistry, physiology, bio-chemistry, micro-biology and bacteriology has been studied over years in many parts of the world. The culture and isolation of microbes under various environmental conditions have been successfully experimented to improve rate of reaction. The conditions, under which cattle dung, organic wastes, bushes, weeds etc. will produce methane, can be understood through chemistry of fermentation.

10.1 Introduction

Winds are the motion of air around the Earth. This movement in air is caused by the uneven heating of the planet’s surface by the sun. The idea of using wind as a form of power is not new. The traditional applications of wind were primarily as sources of kinetic energy for rural, agricultural and a limited number of industrial uses such as pumping water and grinding grain.

Presently wind energy can be used for two major applications, such as wind mills for pumping water for drinking as well as for irrigation purposes and second application is as aero-generator for electricity generation for domestic and industrial uses. In addition to this, presently wind energy battery charger are also available, which can store energy for lights, radio communication, hospital equipment and to power various emergencyrelated equipment.

The wind energy has an enormous resource, but the problems of utilizing the winds are many and varied. Wind energy is very diffuse in nature and local topographical features significantly alter the prevailing winds, thus leading to the extremely site specific nature of wind energy.

Scientists have estimated that as much as 10% of the world’s electricity could be prepared by wind generators by the middle of 21 century. India has estimated wind power potential of 40,000 MW. India now, ranks fourth in the world in wind power generation.

The world’s largest wind farms are in California (USA), where wind turbines can generate power up to about 1120 MW. The first wind mill used as source of electric power was built in Denmark in 1890.

9.1 Introduction

Basically, for heating or cooling the space using solar energy, the solar energy is to be collected, stored and distributed properly in the space to be heated or removed from the space to be cooled. There are two basic approaches for solar houses, there are:

(a)Active solar house technology

(b)Passive solar house technology

In active approach, the solar energy is collected and stored in some separate solar energy collector and then energy is distributed in the space where heating is to be done using electrically operated pumps and fans coupled with radiator etc. The storage of solar energy in active solar house may be in the form of storage as sensible heat or storage as latent heat or chemical heat storage. As per requirement of heating the size of solar collector and storage system be decided. Generally, the active concepts of solar houses are used for heating purpose. Active concept can also be used for space cooling applications. Solar vapor compression and absorption system can be used for this purpose, essentially, this includes incorporation of solar heat collectors, thermal storage system, auxiliary heat supply system (to compensate intermittent nature of sun energy) and control systems. Further, there are three ways of solar space heating i.e. solar air systems, solar liquid systems and solar heat pump systems.

8.1 Introduction

Solar energy can be directly converted into electrical energy. Energy conversion devices which are used to convert sun light into electricity by use of the photovoltaic effect are called solar cells. The advantages of solar cells are:

1.They are reliable, convenient and durable.

2.It is green, sustainable and pollution free technology.

3.Directly solar radiation can be converted into electricity (conversion of global solar light by flat plate photovoltaic).

4.Maintenance cost is quite low therefore suitable even in isolated and remote area, since no moving parts are involved.

5.Solar cells are quite compatible with almost all environments, respond instantaneously with solar radiation.

6.Considerable expected lifetime i.e. 20 years or even more.

7.1 Introduction

A greenhouse is quasi-permanent structure, covered with a transparent or translucent material, ranging from simple homemade designs to sophisticated pre-g\fabricated structures, wherein the environment could be modified suitable for propagation or growing of plants. Materials used to construct a greenhouse frame may be wood, bamboo and steel or even aluminum. Covering can be glass or various rigid or flexible plastic materials. Depending on the covering material, different terminology have been used in the context of greenhouse structures as mentioned below:

Glasshouse: A greenhouse with glass as the covering material is called glasshouse

Polyhouse: It is a greenhouse with polyethylene as the covering material.

6.1. Introduction

Solar crop drying has been demonstrated to be cost effective and an effective alternative to traditional and mechanical drying systems, especially in location with god sunshine during the harvest season. Considerable energy savings can be made with open sun drying since the source of energy is free and sustainable. However, this method of drying is extremely weather dependent and has the problems of contamination, infestation, microbial attacks, etc., thus affecting the product quality. Additionally, the drying time required for a given commodity can be quite long and results in post-harvest losses. Solar drying of agricultural products in enclosed structures by natural convection is an attractive way of reducing post harvest losses and low quality of dried products associated with traditional sun-drying methods. The crop is vulnerable to damage due to hostile weather conditions. The crop is also susceptible to re-absorption of moisture, if it is kept on the ground during periods of no sun, which reduces its quality. This type of problem can be solved by solar dryer. Many dryers have been developed and used to dry agricultural product in order to improve shelf life .Most of these either use expensive sources of energy such as electricity or combination of solar energy and some other form of energy which is not cost effective and dependent on regular supply of fuel.

Principally, drying requires temperature for removing moisture from product, air flow rate to remove moisture from drying chamber and optimum relative humidity within the drying chamber to allow fast drying. These all three requirements for drying can easily be achieved from solar energy. Solar drying is one of the direct applications of solar heat, which involves removal of moisture from the products through the application of solar energy. The removal of moisture requires only low temperature heating, which can be met easily by absorbing solar energy by the surface. This increases the temperature of the air inside the dryer. The moisture produced from the drying product is usually carried out along with the exhaust air. The characteristic of solar energy is good for the drying at low temperature i.e. high flow rates with low temperature rise. The intermittent nature of solar radiation can not affect the drying performance at low temperature. Further, solar energy is available at the site of use and saves transportation cost.

5.1 Introduction

Energy in the form of heat is one of the main energy requirements in domestic, agricultural, industrial and commercial sector of our economy. From an enduse point of view, solar thermal energy finds its application in these areas. Solar thermal energy devices convert radiant energy of the sun into thermal energy for different productive works. In fact, solar energy consists of infrared radiation, it is characteristics of infrared radiation that whenever it falls on any object, it converts into thermal heat energy.

The conversion of sun light into thermal energy is easily or conveniently achieved by means of a metallic or plastic cover, painted black with ordinary black board paint or having selected coating over it and covered with one- or double-glazing cover for transmitting solar radiation inside it. This metallic cover is known as absorber, below it either channels or pipes or passages for allowing entry of water or air are provided, through which heat energy is transferred to working medium either air or water. The absorber plate is covered with suitable thickness of insulating material on its back or sides for preventing loss of heat from the absorber plate. This complete system is enclosed in an airtight box. When exposed to solar radiations, the blackened metallic surface absorbs solar energy and converts into heat. This heat could be used for cooking of food, heating of water and air, evaporation of moisture form the grains etc. In fact, absorber works on the principle of black body, which absorbs maximum and a good absorber, is a good emitter. Hence generated heat could be utilized for different applications.

Horticulture word derived from Latin word: Hortus meaning ‘Garden’ and cultura means ‘cultivation’.

Father of horticulture: Thomas Andrew Knight, John Lindley, Liberty Hyde Bailey.

1^st artificial hybridization in fruit crop in world: T. A. Knight.

Father of vegetables: L. H. Bailey.

1^st book in horticulture: Fruit growing in India: W.B. Hayes (1945) & related to litchi.

Export growth of fresh fruits and vegetables in term of value is 14% and of processed fruits and vegetables is 16.27%.

Contribution of horticulture sector to agriculture GDP (2013-14): 29%.

India is largest producer of Coconut, Cashew, Tea and Spices.

4.1 Introduction

Heat is energy which flows due to difference in temperature. Whereas energy is stored heat. Therefore, when the heat energy transfer is completed. It is stored in the form of potential or kinetic energy, in general as internal energy. Heat as energy is measured in terms of observed changes in other forms of energy & other physical properties. A heat transfer analysis is required for estimating the size, the efficiency and cost of the equipment necessary to transfer a specified amount of heat in a given time. It is well known fact that the size of a solar collector or a heat exchanger depends not so much on the amount of heat to be transmitted but rather on the rate at which heat is to be transferred under given conditions.

4.2 Modes of Heat Transfer

Heat is transferred from one body to another in three possible ways, conduction, convection, and radiation.

3.1 The Sun

The Sun is a star. It is a huge, spinning, glowing sphere of hot gas. It appears so much larger and brighter than the other stars because we are so close to it. The Sun is the center of our Solar System and contains most of the mass in the Solar System. All of the planets in our Solar System, including Earth, orbit around the Sun. In sun the energy generation is a multi-step process of thermo-nuclear fusion reactions. In the thermo nuclear fusion hydrogen (four protons) combines to form helium (one helium nucleus). The mass of the helium nucleus is less than that of four hydrogen protons and mass having been lost in the reaction is converted to energy. The reaction is represented as

2.1 Introduction

The name thermodynamics stems from the Greek words therme (heat) and dynamis (power), which is most descriptive of the early efforts to convert heat into power. It may be defined as the science that deals with the relations among heat, work and properties of a system. Today, thermodynamics is broadly interpreted to include all aspects of energy and energy transformations, including power generation, refrigeration, and relationships among the properties of matter. It is viewed as the science of energy, and thermal engineering is concerned with making the best use of available energy resources.

Thermodynamics basically entails four laws or axioms known as Zeroth, First, Second and Third law of thermodynamics.

The zeroth law deals with thermal equilibrium and establishes a concept of temperature.

The first law pertains to the conservation of energy and introduces the concept of internal energy.

The second law indicates the limit of converting heat into work and introduces the concept of entropy.

The third law defines the absolute zero of entropy.

The concept of energy was introduced by Newton in the field of mechanics during generalizing the hypothesis of kinetic and potential energies. Energy may be defined as the capacity to do work and it is a scalar quantity. It cannot be seen or observed. Its presence can, however, be felt by the properties of the system. There occurs a change in one or more properties of the system in case of energy transfer. The absolute value of energy of a system is difficult to measure, whereas the energy change is rather easy to calculate. Energy follows the conservation law, one of the most fundamental laws of nature, which simply states that during an interaction, energy can change its form from one form to another but the total amount of energy remains constant, that is, energy cannot be created or destroyed only form can be changed.

1.1 General

Renewable technologies are considered to be clean sources of energy. The optimal use of these resources minimize environmental impacts, produce minimum secondary wastes, and are sustainable based on current and future economic and social needs. Sustainable development requires methods and tools to measure and compare human activities’ and its environmental impacts for various products. Renewable energy sources (RES), which include biomass, hydropower, geothermal, solar, wind, and marine energies, supply 14% of the world’s total energy demand. Renewable resources refer to primary, domestic, and clean or inexhaustible energy resources. Large-scale hydropower energy supplies 20 % of the global electricity need. Wind power in coastal and other windy regions is a promising source of energy.

Renewable energy resources can make a decisive contribution to the economic, social and sustainable development of rural regions in developing countries, yet the consumption of fossil fuels is dramatically increasing along with improvements in the quality of life, the industrialization of developing nations, and the increase of the world’s population. It has long been recognized that excessive consumption of fossil fuel leads not only to a diminishing fossil fuel reserves more quickly, but also has a significant adverse impact on the environment. Such impacts result in increased health risks and the threat of global climate change. Changes to improve environmental conditions are becoming more politically acceptable globally, especially in developed countries. Society is slowly moving towards seeking more sustainable production methods, minimizing waste, reducing air pollution from vehicles, generating distributed energy, conserving of native forests, and reducing greenhouse gas emissions. Increasing consumption of fossil fuel to meet out current energy demands, however, has sounded alarms over regarding potential energy crisis. This has generated a resurgence of interest in promoting renewable alternatives to meet the developing world’s growing energy needs. Excessive use of fossil fuels has caused global warming from carbon dioxide emissions, therefore, promoting renewable forms of clean energy is eagerly required. To monitor the level of these greenhouse gas emissions, an agreement that has fulfills the objectives of the Kyoto Protocol was create with overall pollution prevention targets.