eChapters

In the wild (forests) plants grow by their own, but in agriculture because of limited space they don’t have freedom to grow in a much natural way. This can lead to structural irregularities in their growth, and can hamper the overall plant’s development and this will impact the produce or crop yield. To deal with such constraints and to boost the crop production, the methods of thinning and pruning provide efficient ways to train the growth of young plants and maintain the health of grown-up plants.

11.1 Introduction

In agriculture, thinning means the removal of some plants or some parts of plants that show inconsistent growth and or are damaged by some pest or disease, without removing the whole tree or plant. The selective removal of branches, buds or roots is termed as pruning [1]. If the plants are overcrowded in a confined space, the overall health of the crop decreases due to the competitive stress from the neighbouring plants. Thinning and pruning is done to improve the growth rate or health of the plants by decreasing the competitive stress. Thinning and pruning in agriculture is the sensible removal of plant parts such as flowers, shoots, its branches or other parts to correct or maintain that structure of the tree and control be directed growth of the crop. This practice covers the precise removal of the unhealthy and obstructive part of the plant branch, leaves, fruits, buds, fruits, etc. Pruning improves the quality and longevity of the crop, leading to quality produce and increased yield of the field. This also helps in increasing the size of the fruit as it increases the availability of nitrogen required for growing and stimulating growth of the crop. There are several factors that influence the amount of pruning to be done, i.e., age of the plant, condition of the bark and wood, growth characteristics, whether cup crop/plantation is permanent or seasonal [2]. Pruning is done for controlling the size of the plant, controlling the structure makeup of the plant, controlling and improving the light distribution of the plants by the selective removal of leaves to improve the quality of the fruits, removing the diseased parts of the plant and to regulate the fruit crop and increase the life of the tree.

The principle behind thinning and pruning is to admit more sunlight to the branches that bear fruit by the selective removal of the unproductive branches which obstruct the sunlight to fall on the productive branches to increase the productivity white and vitality of the plant to obtain optimum healed of good quality crop [3]. Young trees are pruned so that they acquire the desired shape. In old trees it is done to stimulate flowering. In plants bearing fruits or crops, pruning is done to allow adequate sunlight to fall on fruit bearing branches, so that quality crop is produced. Very old plants heavy pruning is done to restore the vigour of the plant. It is also done so that the loss of nutrients being shared by the diseased peak or shading branches is reduced. The use of robotics and other automated systems can aid in the precise pruning and thinning of the crop. This will also automate the whole process and will save their requirement on the extensive manpower which ultimately saves time.

To cater the increased demand of food, it will be required that farmers are equipped with tools and methods to improve their yields and make informed decisions [1]. Also, with the increase in population, the agricultural land is decreasing by 1 lakh hectares per year and it is required to double the agricultural produce in the next 30 years to sustain the global food requirements.

The improvements in various technological fields like machine learning, navigation, robotics etc. and their applications in agriculture is required to meet this increasing need. One of the factors is to make the farmland ready for sowing the crops, spraying, etc. and this has to be done in a precise and faster manner to address the latter issues. So, the uses of autonomous tractors for such jobs offer accurate, precise and timely preparation of the fields for the cultivation.

12.1 Introduction

Autonomous tractors or driverless tractors are unmanned ground vehicles mainly employed in agriculture for various purpose like preparation of land for the crops, harvesting, spraying, and other agricultural purposes. They are equipped with GPS, autopilot, cameras, lasers (LiDAR), and other wireless technologies navigation and mutual coordination and offer saving of both the manpower and time. These autonomous tractors can be programmed to navigate their paths through the fields and are designed to avoid the obstacles while doing their jobs. These tractors automate various laborious field jobs and also minimize human intervention in the process.

These autonomous machines are regarded to revolutionize the agriculture industry and offer safety, sharing of resources, economical solutions per square area of land, etc. Several industries like Jhon Dheere, AgraBots, EcoRobotix, RowBot, etc.

Harvesting is one of the most labour intensive jobs in agriculture, and by implying the robotics in harvesting, the quantity of the harvested yield can be readily increased, thus saving a lot of time and human resources. This also aids in reducing the farm to market transportation times. The use of robotics can also reduce the seasonal requirement of the manual labour and thus reduce the recurring costs.

13.1 Introduction

The incorporation of robotics in agriculture has proved to be advantages for the farmers and thus for the economy. The automation of various agricultural processes led to the reduction of the operational costs and also in the reduction of the labour required. A possible solution to address the problems of labour availability and scaling up the harvesting of the crop is the incorporation of robotics.

The development of the civilisation humans have tried to domesticate the animals. Initially dogs were known to be the first pet domesticated by humans followed by the domestication of other animals like cattle, horses, sheep etc.

14.1 Introduction

When humans started to domesticate the animal, they have tried several ways to control them. Generally these animals are released in free space to graze and one of the known problems is to prevent them from overgrazing. So building a fence is one of the ways to limit their movement is one viable solution, but building a fence is limited to a smaller area. Since these animals are locked in a large number, so building a bigger fence and moving it every time for grazing is not viable. It can be observed in the history of humankind as that civilisation progressed the use of Shepherd dogs has been one of the widely accepted. Shepherd dogs not only help in shepherding and herding but also prevents these livestock from wolves

The incorporation of robotics will not only automate the process intelligently but also keep a vigil on various aspects of livestock management. In recent years there has been a substantial development in this regard. The development of robotic dogs for shepherding and herding purposes has found a lot of increment developments. SPOT developed by Boston dynamics and SwagBot developed by University of Sydney, are well-known robots developed in recent times for the purpose.

These robots are equipped with multiple sensors like LiDAR, gas and heat sensors, high-resolution cameras etc. The array of sensors are used to capture the data in real-time and is then used for decision-making processes. Also these reports are built to be rugged and can navigate on a variety of terrains.

Milk revolution with change in technology is gaining attention in India. Robotic milking reduces labour and increases efficiency irrespective of large dairy farms. A typical system requires a large camera- and spray-system robot. When activated to apply the disinfectant, the robot sends a six-foot- long pipe with the sprayer under the cow. These floor-mounted robots require expensive installation into the floor of the milking parlour, as well as fencing for employee protection.

15.1 Introduction

Mechanical draining has increased broad acknowledgment, especially in Western Europe, as an approach to lessen labor on dairy ranches, increment creation per cow, and improve the way of life of dairy ranch families draining 40 to 250 cows (De Koning, 2010). The developing ubiquity of this innovation is obvious in its fast pace. In 2009, the evaluated number of automated dairy ranches overall was 8,000 (De Koning, 2010). Only 6yr later, Barkema et al. (2015) proposed that this number had dramatically multiplied to 25,000 dairy ranches around the world. The level of groups utilizing this technology is most noteworthy in Scandinavian nations and the Netherlands (Barkema et al., 2015). Broad selection in these nations proposes in any event a proportion of accomplishment in helping dairy ranchers accomplish more noteworthy work productivity and a superior way of life, yet field experience recommends that wide variety exists in the measure of work spared and in the general fulfilment of early adopters.

Ber (Ziziphus maruritiana Lam.) is cultivated all over the desert part of the Indian subcontinent for its fresh fruits, which are rich in vitamin C, vitamin A and vitamin B-complex and minerals. It can be successfully cultivated even in the most marginal ecosystems of the subtropics and tropics. Ber or Indian jujube belongs to the genus Zizphus of the family Rhamnaceae and order Rhamnales. Ber is adopted to ecologically poor, drought prone areas, which encounter recurrent crop failures and thereby economic crises. It yields nutritious fruit, rich in vitamins and minerals than apple even in drought years and its cultivation is highly cost effective owing to very low input requirement. Ber cultivation also provides employment for people in different farm operations for production and sale of the produce. In India, Haryana, Punjab, Uttar Pradesh, Rajasthan, Gujarat, Madhya Pradesh, Bihar, Maharashtra, Andhra Pradesh and Tamil Nadu are major ber producing states. The area under cultivation with this fruit is 8.7 lakh ha with an annual production of 8.9 lakh tones in India (Baloda et al., 2012). About 125 varieties of ber are available in India. A few of these varieties are known for taste, size, amount of pulp and higher yields. The cultivars Umran, Kathapal and Gola are the most promising varieties of ber in North India (Azam-Ali et al., 2001).

Nutritive Value

Many people are unaware that the ber is one of the most nutritive fruit, since ber is a common fruit. It is one of the richest sources of vitamin C, next only to aonla and Guava but better than citrus fruit and apple. The fruit pulp contains 13-20% total soluble solids and 0.20-0.80% acidity at fully ripened fruit. Ripe fruit of Umran contains 117 mg ascorbic acid/100 g of pulp. Ber fruit contains β-carotene (vitamin-A) at 81 µg/100 g of fruit, 5.6% sucrose, 1.54% glucose, 2.08% fructose, 1.00% starch and 1.13% total carbohydrates. Due this, so ber is often called the “poor man’s fruit”. Table 1 represent the nutritional composition of different ber varieties.

Cape gooseberry is the native of Peru and Chili (South America), but widely cultivated in Cape of Good Hope and hence called so. It is known by different name in various parts of the world. It is commonly called ‘Poha’ in Hawaii; ‘Golden berry’,’ Pompelmoes’ or ‘Apelliefie’ in South Africa; ‘Lobolobophan’ in the Philippines. In India it is commonly called ‘Rasbhari’, ‘Makoi’, ‘Tiparee’ or ‘Tepari’. Cape goose berry (Physalise peruviana L.) belongs to the family solanaceae. Out of 80 species of genus physalis, only three are well known for their fruit value. These are: (i) P. pubescen L. (ii) P. Peruviana L., and (iii) P. ixocarpa Brot. However these three species, Physalise peruviana L is the most popular due to its pleasant flavour and acid-sweet taste.

Chicory (Cichorium intybus L. var. sativum D.C.) plant is the herbaceous, perennial plant and supposed to have descended from the wild chicory (wild succory, blue sailors) which is often seen along roadsides with its blue flowers. The leaves are used as salads in human diet and other different purposes. They were reported to be stomachic (Baumann 1982, Franke, 1981) and their juice was used against eye disease and poisoning. The infusion of chicory was believed to be good for the liver, kidney and stomach. Initially the wild plant was used but since approximately 300 B.C., the crop was cultivated for this purpose. Beverages, soups and sauces made of chicory were reported to be used in Italy and Belgium as early in 16^th century.

For the first time, the root of chicory was used as a substitute of coffee in 1690 in Holland followed by many other countries like Sweden, France, etc. During 1806 and 1813, the cultivation and use of roasted roots of chicory as coffee substitute spread over the whole European continent. In the 19^th century, the main centres of cultivation of chicory were North-East France, Belgium, England, Russia, Holland and Australia. Subsequently it was raised on large scale in Poland, Hungary, Germany, Switzerland and India. Presently over 20% of the World’s consumption takes place in Eastern Europe, especially in Poland (6%) followed by Russia, Hungary, Romania, Czechoslovakia and East Germany. Twelve percent is reported to be consumed in South Africa, 9% in India and 2% in the United States (Clark and Macrae, 1987).

Ginger is used extensively as a spice in cuisines throughout the world. Ginger belongs to Zingiberaceae family and an English botanist William Roscoe (1753-1831) gave this plant the name Zingiber officinale in the year 1807. The name of the genus Zingiber derives from a Sanskrit word denoting “horn shaped” in reference to the protusions on the rhizomes (Ghosh et al., 2011). It is an oldest rhizome widely domesticated as a spice where the edible part is the swollen underground stem or rhizome. The Zingiberaceous plants have strong aromatic and medicinal properties and are characterized by their tuberous or non-tuberous rhizomes (Chen et al., 2008). Ginger is a medicinal plant that has been widely used all over the world, since antiquity, for a wide array of unrelated ailments including arthritis, cramps, rheumatism, sprains, sore throats, muscular aches, pains, constipation, vomiting, hypertension, indigestion, dementia, fever and infectious diseases (Ali et al., 2008). Ginger has direct anti-microbial activity and thus can be used in treatment of bacterial infections (Tan and Vanitha, 2004).

Mushrooms are good as nutritious food for all ages and under all conditions of health. The mushroom is a fleshy, space-bearing organ of non-green edible fungi. Its fleshy nature of mushroom is responsible for its main attraction to human being as a source of food. Like other fruit and vegetables, mushrooms are soft textured and highly perishable in nature. Mushroom are potential sources of nutrients. They can convert nutritionally valueless substances into high fat and protein food. Mushroom proteins are comparable to muscle protein in nutritive value. Being a good source of vitamins and proteins it is considered be a distinct food. The digestibility of protein in these is 72-83%. Mushrooms are edible fungi; assume considerable importance in human diet as they are good source of non starchy carbohydrate, dietary fibre, minerals and vitamins-B and essential amino acids. Mushrooms are popular their delicacy and flavour rather that food value. However, it is now a well-established fact that they are excellent sources of vitamins and minerals (Vijaya Khader, 1988). The vitamins in mushroom are well retained during cooking, canning, and dehydration. The White button mushrooms (Agaricus bisporus), Shiitake mushroom (Lentinus edodes), Pleurotus species (Pleurotus osteatus, P. flabellatus, P. sajor caju etc.), Paddy straw mushrooms (Volvariella volvacea), Winter mushrooms (Flammulina velutipis), Jew’s ear mushrooms (Auricularia polytricha) are commercially cultivated species of mushroom. In India, mainly three species viz., white button, oyster or dhingari and paddy straw mushrooms are commercially cultivated at large scale.

Tropical fruit tree are important crops which supplement and improve the quality of diet. Many of the species have multi-purpose uses in that they produce non food products such as fuel, timber, fodder, medicines and industrial products for small holders. Harvesting from these trees enable rural people to provide nutrition for a balanced diet and generate income thus alleviate poverty. Tamarind (Tamarindus indica L) can be found throughout much of the tropics, it is grown unattended in backyards, roadsides or waste lands. Tamarind is ideally suited for avenue plantings as a roadsides tree, in and around villages as a multipurpose species for agro-forestry system or as protective firebreaks for forest margins. It is a valuable timber species widely used for making furniture, tool handles, charcoal, oil mills, rice pounders and fuel wood. The leaves are an important source of food and herbal medicine and the edible pulp of ripe fruits is used as a flavouring agent in cooking, soups, jams, chutneys, sauces, pickles etc. The fruit pulp of tamarind forms the “Tamarind of Commerce”. The name tamarind is derived from the Arabic word ‘Tamar-u’l-Hind’ because the dark brown pulp of the fruit was thought to resemble dried dates. It was therefore called the Tamere-hindi or ‘date of India. The production of Tamarind in India was estimated 201000 tonees for year 2017-18 (Horticulture statistics, 2018), India is the world’s largest producer of tamarind products. It is particularly abundant in the India states of Madhya Pradesh, Bihar, Andhra Pradesh, Karnataka, Tamil Nadu and West Bengal. The production in India is mainly concentrated in the drier southern states and the produce is collected by the villagers and sold in the market. In India, the average production of tamarind pods per tree is 175 kg and processed pulp is 70 kg/tree (Kulkarni et al., 1993).

A large number of people in developing countries have traditionally depends on products derived from plants, especially from forests, for curing human and livestock ailments. Additionally, several aromatic plants are popular for domestic and commercial uses. Collectively they are called medicinal and aromatic plants (MAPs). About 12.5% of the 4,22,000 plant species documented worldwide are reported to have medicinal values. With dwindling supplies from natural sources and increasing global demand, the medicinal and aromatic plants, will need to be cultivated to ensure their regular supply for processing and value added products.

The term “Medicinal and Aromatic plants” generally denotes those non-aromatic and aromatic plants, which are used for medicinal, perfumery, dye and cosmetic purposes. They are rich in secondary metabolites and are potential sources of drugs. Generally the whole plant roots, stem, bark, leaves, flowers, fruits, gums and oleoresins, etc. are used.

India has been considered as treasure house of valuable medicinal and aromatic plant species. Ministry of Environment and Forests have identified and documented over 9500 plant species considering their importance in the pharmaceutical industry. In the present context of ‘back to nature’ in health care, it is relevant that these valuable plant species are not only preserved but also their cultivation developed in order to meet the entire demand of the domestic industries as also to exploit the bright prospect for export. Shift from collection to cultivation of medicinal & aromatic plants will also ensure purity, authenticity and sustainable supply of raw materials required for herbal drugs, including polyherbals.

India has a population of one hundred twenty four crore plus and feeding this large a population calls for a strong FPI. The industry also assumes importance in the national economy due to the immense employment generation opportunities it offers and the export revenue it earns. Food Processing Industry (FPI) in India is a sunrise sector that has gained prominence in the recent years. Easy availability of raw materials, changing lifestyles and favourable fiscal policies has given a considerable push to the industry’s growth. FPI serves as a vital link between the agriculture and manufacturing sectors of the economy. Strengthening this link is critical to reduce wastage of agricultural raw materials, improve the value of agricultural produce by increasing shelf-life as well as by fortifying the nutritive value of the food products and ensure remunerative prices to farmers as well as affordable prices to consumers. The industry has very low processing level i.e., 2.2% for fruits and vegetables, around 35% in milk, 21% in meat and 6% in poultry products, which is significantly lower by international standards. For e.g., processing of agriculture produce is around 40% in China, 30% in Thailand, 70% in Brazil, 78% in the Philippines and 80% in Malaysia. Value addition to agriculture produce in India is just 20% with wastage estimated to be valued at around US $13 billion.

India has the second largest producer of food with arable land of 159.65 million hectares and has the highest acreage under irrigation. Next to China, India ranks second largest food producer in the world and has the potential to immerge the biggest with its food and agricultural sector. India accounts for less than 1.5% of international food trade despite being one of the world’s major food producers, which indicates huge potential for both investors and exporters. Food and food products are the biggest consumption category in India

The major components of foods are the protein, carbohydrates and fat. The spoilage of foods containing fats includes the deterioration of the fatty components; the principal difficulties found in their preservation are in the development of rancidity. The spoilage of fats and oils has received much attention and substantial progress has been made in their preservation. One of the major causes of food deterioration is the chemical oxidation of unsaturated fatty acids in the lipids present in all foods. These fats are present in fat deposits and in cell membranes. End products of lipids oxidation, mainly aldehydes and ketones, contribute to the rancid off flavour and odours in the foods.

Fatty acids in food occur in the form of esters with the alcohol. The predominant esters are triacylglycerols accompanied by minor amounts of mono- and diacylglycerols and free fatty acids. The unsaturated bonds present in all fats and oils represent active sites that can react with oxygen. This reaction leads to formation of primary, secondary, and tertiary oxidation products that may make the fat or fat containing food unsuitable for consumption. Other consequences of oxidation include discolouration; changes in the texture, flavour and taste; and loss of nutritional value due to the destruction of essential fatty acids as well vitamins. Unsaturated fatty acids are subject to oxidation at their double bonds. In the presence of suitable catalysts, or in contact with lipooxidase enzymes, long chained unsaturated fatty acids may be fragmented to short chained fatty acids. The cleavage usually involves an intermediate peroxide formation. Many chemicals compounds aid in food preservation to protect the nutrients, flavour and texture, and storage stability of food stuff for longer period.

A white to light brown powder, is a heteropolysaccharide derived from the cell wall of higher terrestrial plants. It is mainly used in food as a gelling agent in jams and jellies. Today it is also used in fillings, sweets, as a stabiliser in fruit juices and milk drinks and as a source of dietary fiber in foods. Pectin is a heterogeneous grouping of acidic structural polysaccharides, found in fruit and vegetables and mainly prepared from ‘waste’ citrus peel and apple pomace. Pectin has a complex structure. Preparations consist of sub-structural entities that depend on their source and extraction methodology. Commercial extraction causes extensive degradation of the neutral sugar-containing side chains.

Pectin was first isolated and described in 1825 by Henri Braconnot, though the action of pectin to make jams and marmalades was known long before. To obtain well set jams from fruits that had little or only poor quality pectin, pectin-rich fruits or their extracts were mixed into the recipe. During industrialization, the makers of fruit preserves soon turned to producers of apple juice to obtain dried apple pomace that was then cooked to extract pectin. Later, in the 1920s and 1930s, factories were built that commercially extracted pectin from dried apple-pomace and later citrus-peel in regions that produced apple juice in both the USA and in Europe. At first pectin was sold as a liquid extract, but nowadays pectin is often used as dried powder that is easier to store and handle than a liquid

Fruit and vegetables play an important role in human nutrition. They are vital source of essential minerals, vitamins and dietary fibre and supply complex carbohydrate and protein. They are good source of calcium, phosphorus, iron and magnesium and contribute over 90% of dietary vitamin C. Green and yellow fruits and vegetables are a rich source of vitamin A (β-carotene). Thiamine, niacin and folic acid, which are required for normal functioning of the human body, are also present in significant qualities. Fruit is an important food in diet designed to reduce the risk of coronary heart disease in developed countries. It is not surprising, then, that certain fruit components exert pharmacological or therapeutic effect. The antioxidant properties of β -carotene may also a role in prevention of some forms of cancers. Packing and handling systems have been developed to move the product from farm to consumer expeditiously in order to minimize quality degradation. Food irradiation is a physical process like drying, freezing, thermal processing (canning and pasteurization) that can be used to disinfest, sterile and preserve food. The use of chemical preservatives to inhibit the growth of spoilage bacteria in modern food system has been recognized as deterrent to health. The present day, customer demands food products with no chemical preservatives, free from additives, natural with assured safety and better long shelf life.

The deterioration in foods during storage may include loses in organoleptic desirability, nutritional value, safety and aesthetic appeal. Food is subjected to physical, chemical and biological deterioration. Heat, cold, light, humidity, other radiation, gas composition, moisture, dryness, natural food enzymes, micro and macro organism, and industrial contaminants are adversely affect the food quality and their shelf life. The practice of drying, curing and fermentation are among the conventional methods of preservation used for thousand years.

The paddy grain contains a rough outer covering called husk. It accounts for about one-fifth to one - fourth of the weight of paddy. The inner kernel, called brown rice or dehusked rice, again contains some soft outer layers, jointly called bran. It accounts for about 6-8% of the brown rice weight, including the small germ (1-2% by weight) located in one corner. Rice milling is the process of removing the husk and a part of the bran from paddy in order to produce edible rice. Rice milling system ranges from the home-scale to the large, complex modern rice-processing installations. They include hand-pounding equipment, single hullers, emery sheller-cum-huller mills, emery sheller-cum-cone polisher mills and the modern rubber – roller rice mills. Rice milling industry does not only mill rice but it also carries many other essential functions, such as cleaning and grading, drying, storage, quality control etc. for the production of better quality rice. All these processes are discussed in this paper.

Unlike other food grains, rice is mostly consumed as cooked whole grain, Milling technology is therefore geared to obtain maximum outturn of milled rice and to reduce breakage to the minimum. The single huller mills are by and large located in villages or in localities where paddy is custom milled for produces and they still handle the bulk of the country’s production. The large-capacity rice mills located in urban or semi-urban areas for commercial milling are of ½ to 4 tones per hour capacity and handle the rest of the paddy milled. Some battery hullers are still in operation as large commercial mills, specially for milling parboiled paddy.

Foods are classified into three groups on the basis of ease of spoilage. Spoilage meant a condition produced by the excessive growth of microorganisms leading gradually to decay or decomposition. The stable or non perishable foods like sugar, flour, grains and dry products do not ordinarily spoil unless handled carelessly. The semi-perishable food like potatoes, onions, apples, waxed fruits, fruits and vegetables having thick skin can be protected from spoilage if properly handled and processed. The perishable foods, like livestock products, seafood, and poultry items, dairy products, and most fruit and vegetables spoil readily unless special preservatives methods are used. The spoilage of foods may be caused by molds, yeast, bacteria, enzymes, food constituents and insects. The use of food additives have become necessary to prevent spoilage other wise caused by the growth of bacteria, yeasts and molds.

Food spoilage usually refers to undesirable changes occurring in food due to the action of micro-organisms, insects and enzymes. The original nutritional value, texture, flavour of the food are damaged, the food become harmful to people and unsuitable to eat. Today however, preservation has used such factors as temperature, water activity, pH, gases, organic acids, salts, antibiotics, irradiation, packaging and various combinations of these factors. Foods vary greatly in the length of time for which they can be held in their natural form without spoilage. Preservatives retard product spoilage caused by mold, air, bacteria, fungi or yeast. Bacterial contamination can cause food-borne illness, including life-threatening botulism.

In India, people are mostly vegetarian, depending largely on cereals and pulses, as their staple foods, which provide the main source of dietary proteins and calories. The proteins from pulses are known to be inferior quality, due to the deficiency of sulphur containing amino acids as well as due to other factors like digestibility, availability of amino acids, anti-nutritional factors, etc. The anti-nutritional factors present in this type of food, including their contents of enzyme inhibitors, lectins, flatulence factors, tannins, phytic acid and saponins. Anti-nutritional factors can cause detrimental effects to humans and animal growth and performance by impairing intake, uptake, or utilization of other food and feed components, or by causing discomfort and stress to humans and animals. The anti-nutritional factors mainly occur in pulses and grain legumes and foods and feed material prepared from grain legumes and pulses.

Substance which, from nutritional point of view, interferes with normal growth, reproduction or health when consumed regularly in amount existing in a normal component of diet should be considered as harmful and toxic. A significant part of human population relies on legumes as staple food for subsistence, particularly in combination with cereals. They are unique foods because their rich nutrient content including starch, protein, dietary fibre, oligosaccharides, phytochemicals (especially the isoflavones in soybean) and minerals. Their nutritional contents contribute to many health benefits to human.

Food technologies now have more sweeteners from which to choose than ever before. With the obesity epidemic and the public attention it currently receives, plus the increasing interest in foods with added benefits sweeteners that allow for consumer appealing labeling are of particular interest. These sweeteners fall into basic categories, those that are essentially calories free, often referred to as low-calories or intense sweeteners, and those, which are significantly reduced in calories, which may be referred to as reduced calories-sweeteners, bulk sweeteners, or sugar replaces. These sweeteners when used alone or in combination may permit such labeling as ‘low-calories’, ‘reduced-calories’, ‘light’ ‘sugar-free’ and ‘dose not promote tooth decay’.

The ideal sweeteners does not exist, it would be at least as sweet as sucrose and provide the same properties to a product as sucrose, with processing parameters similar to those of sucrose so that existing equipment can be used. It would be colourless, odourless and noncariogenic, with a clean, pleasant taste and have immediate onset and not much lingering. Solubility and stability are important. The ideal sweetener must be compatible with a wide range of food ingredients because sweetness is but one element of a complex food flavour system. Even sucrose is not perfect, being unsuitable for some applications.

Extrusion cooking is an emerging technology having advantages of low production cost, capable of producing end products in various shapes and sizes, from a variety of food materials with easy digestibility, maintaining hygiene and high product quality and leaving no effluents or hazardous materials. Minimal energy consumption and processing costs and possibility of flavour addition are the added advantages of technology. The process/technique has the versality and ability to constituently produce a given product in continuity at a given set of pre – determined specifications. It destroys fat splitting enzymes to avoid rancidity and thus extends the shelf life of products considerably. Microorganisms present in food materials are destroyed. It can be effectively utilized to develop functional and designer foods by using several locally available under-utilized food materials. However, it leads to increased package cost as puffed or expanded food products have low bulk density. R & D studies are further needed for co – extrusion of variety of cereals with high fibre content foods and micronutrients.

Fruit jelly is an important part of diet of all human being. It is easily digestible, highly refreshing, appetizing and nutritionally far superior to many foods. Today, a wide variety of fruit jellies are consumed in the home, at work place and sport stadium. There has been considerable increase in the consumption of fruit and vegetable jellies in the world during last few years. Jelly is a semi-solid product prepared by boiling a clear strained fruit extract free from pulp after the addition of required amount of sugar, citric acid and pectin. It should contain minimum 65 percent of total soluble solids and minimum 45 percent of fruit portion (Dhawan, 1998). Guava is rich source of pectin and acid content and have thick flesh is preferred for jelly making. For getting good quality jelly, mix under-ripe fruits give better pectin content and ripe fruits provide the flavor. Winter season fruits yield better quality jelly (Singh and Dhawan, 1983). It is a clear or translucent fruit spread made from sweetened fruit (or vegetable) juice and set using naturally occurring pectin. Additional pectin may be added where the original fruit does not supply enough. Jelly can be made from sweet, savory or hot ingredients. It is made by a process similar to that used for making jam, with the additional step of filtering out the fruit pulp after the initial heating.

Jellies are the products used as bread spreads all over the world. These are made from fruits rich in pectin. Guava, because of its rich pectin content, is processed into jelly. Processing of guava into jelly is practiced by processors all over the world. Colouring of jams and jellies has been an age old practices colorants. Great attention is being paid now days to the usage of natural colours in view of the hazards that the synthetic colours pose to human health. Incorporation of carrot resulted in colour improvement over control. Jelly containing carrot as a colouring source was found slightly better than other vegetables. Jelly is a semi-solid product prepared by boiling a clear strained fruit extract free from pulp after the addition of required amount of sugar, citric acid and pectin. It should contain minimum 65% of total soluble solids and minimum 45% of fruit portion (Dhawan, 1998).

Much of the post-harvest losses of fruits and vegetables in developing countries is due to the lack of proper storage facilities. While refrigerated cool stores are the best method of preserving fruits and vegetables they are expensive to buy and run. Consequently, in developing countries there is an interest in simple low-cost alternatives, many of which depend on evaporative cooling which is simple and does not require any external power supply. India is the second largest producer of fruits and vegetables in the world after Brazil and China respectively. Storage of fresh horticultural produce after harvest is one of the most pressing problems of a tropical country like India. India’s total fruits and vegetables production is lost during harvest, storage, grading, transport, packaging and distribution in a year which reduces the growers share. Due to their highly perishable nature, about 20-40% of total fruit and vegetable production go waste during various steps of the post-harvest chain, smooth transport and insufficient cool storage space/ facility at farmer’s level and high cost of refrigerated storage so further enhances loss of fruits and vegetables. Temperature and humidity play major role in storage of fruits and vegetables Temperature can be controlled by using energy consuming methods such as air-cooling, hydro-cooling, vacuum-cooling, chilling, ice cooling, freezing, etc.

Food is a complex system of inorganic and organic compounds. These compounds are present in food in unique combination and uniquely organized structures, and therefore, every type of food has unique characteristics, nutritive value, sensory quality, texture, etc. Food items are always in physical, chemical and biological dynamics, however rate of change vary from food to food. Those highly perishable in nature undergo faster rate of spoilage as compare to those semi-perishable or stable. Foods are affected by nearly every variable of environment. Heat, cold, light or other radiations, oxygen, moisture/dryness, natural food enzymes, microorganisms, macro-organisms, industrials and agricultural contaminants, time, etc. - all adversely affect the foods resulting to its spoilage or deterioration. Spoilage may be referred to the losses in nutritive value, sensory desirability, safety and aesthetic appeal to the unacceptable level. Level of unacceptability is the subject of socio-economic status and policies of the state. A food which is of unacceptable quality for one society may be of acceptable quality for other society.

History reveals that food was the root cause of many wars and also the battles were won or lost over food spoilage and its control. Wars and the need to provide safe food to armies in the region far away from the areas of their production have always focused attention on the problem of food spoilage, and this valid today even. Some of the most important advancements in the technology of food preservation were made during the war-time. Of these, most important was the technology of preventing food from spoilage for months together developed by French scientist Nicolas Appert for French army. He won awarded money of 12,000 Francs in 1908 for this. The World learnt the art of canning foods in which the food is packed in a sealed metal container and heated sufficiently. He, however, could not explain the principle behind the preservation by canning. Some 50 years later, work of Louis Pasteur explained that the growth of microorganisms was the major cause of food spoilage which are killed in Appert’s method of preservation.

Fruits and vegetables are very important food commodities not only in developing country like India but all over the world. India, which is the most densely populated country in Asia continent, is still struggling to achieve self-sufficiency to feed about 135 crores people. For this purpose, fruits and vegetables have got their specific importance to provide a balance and healthy diet to the Indian people. Therefore, the reduction of post-harvest loss of fruit and vegetables is a complementary means for increasing production. It may not be necessary to considerably step up the production of fruits and vegetables with the growing demand if the post-harvest loss is reduced to a great extent. The cost of preventing losses after harvest in general is less than preventing a similar additional amount of fruit and vegetable crop of the same quality

Fruits are important source of Pro-vitamin A and vitamin C. In addition, vegetables also supply fair amount of carbohydrates, protein and energy and add colour, flavour and aroma to human diet. India is one of the largest producers of fruits and vegetables. Fruits and vegetables are an important supplement to the human balanced diet as they provide the essential minerals, vitamins and dietary fibre (roughage) for maintaining the tear and wear of the over body. Fresh fruit and vegetables have a short shelf life under ambient conditions of temperature and humidity due to their highly perishable nature. They soon lose their freshness and become subjected to mould and bacterial attack, and consequently decay and become useless as articles of human diet. Fresh fruits and vegetables are valued for their quick sources of available energy. Fresh fruits have high water content (70-96%), varying amount of carbohydrate (3-27%) and fibre (0.2-3.1%) and a low content of protein, fat and minerals. Ideal climatic conditions ensure round the year availability of broad range of fruit and vegetables in large quantities. The production of fruits and vegetables was 97.00 MT and 179.60 MT during the 2017-2018 in India

India is today the second largest producer of fruit and vegetable after China with a total annual production of 281.75 million tons in 2017-18. Fruit and vegetables are essential components of the human diet and nutrition constitute. Fruit and vegetable are also element of diversification in agriculture for additional income generating resource and employment generation area. Although India is the largest producer of fruit in the world, the production per capita is only about 100 g per day. Huge losses to the extent of 20 to 40% of the total production are reported due to lack of adequate infrastructure and transportation facilities and higher the transportation cost. Thus the per capita availability of fruits is further reduced to 60 -80 g per day which is almost half the requirement for a balanced diet. The fruit production in India has recorded a growth rate of 3.9%, whereas the fruit processing sector has grown at about 20% per annum. However, the growth rates have been extensively higher for frozen fruits and vegetables (121%) and dehydrated fruits and vegetables (24%).

Fruit and vegetables are mostly seasonal crops but they are demanded by consumers throughout the year. They are very highly perishable in nature, which is difficult to preserve for the longer period of time under ambient storage conditions. The low temperature storage retarded the activity of various biological and biochemical agents of spoilage and provides longer shelf life to the fruit and vegetables The temperature is brought down by taking out the heat with the help of mechanical refrigeration, This system is based on a liquid absorbing heat as it change to a gas. The more common mechanical refrigeration system use a refrigerant such as (Ammonia, Freon etc.,) takes out the heat from the chamber/ store as it is expand. The spoilage agents are microorganism such as (e.g., bacteria, yeast and molds etc.) and larva. Optimum storage temperature for most products is one slightly above the freezing point of the product. Some fruit and vegetables are particularly sensitive to storage temperature are susceptible to called storage disease when stored at temperature below as or above the critical temperature e.g.,

Packaging is essential for the safe and easy marketing of any food products and for the retention of their natural characteristics till consumed or utilized otherwise. Packaging is also an essential part of processing and distribution of foods. Packaging used for processed foods can contribute marketing to the retention of the quality characteristics. It must protect a variety of assaults including physical damage, chemical attack and contamination from biological vectors including microorganisms, insects and rodents. Environmental factors such as oxygen and water vapour will spoil foods if they are allowed to enter packages freely. Contamination of foods by microorganism can spoil foods or cause life-threatening diseases. With dehydrated food, packaging serves a multi protection role. Depending on the product being packed, packaging has to provide protection against moisture pick up, loss of volatile components, oxidation and damage of product itself. With the development of food industries, use of different types of plastic containers becomes widely popular owing to its several advantages.

Although packaging has, in recent years, been accused of using up valuable resources, it is nevertheless absolutely essential. Packaging is vital to protect and conserve the items contained within it. The dominant purpose of packaging is to protect the product so that it reaches the consumer in the same condition as when it was first made. However there is a lot more to the effectiveness and usefulness of packaging than just protection. When a consumer picks up their carton of freshly squeezed mango juice, they are not aware of the energy and money saved by the packaging they are grasping in their hands. In order to fully understand the essential role packaging plays in every day life, it is necessary to understand the guiding principles behind it.

Food is a major determinant of health, nutritional status and productivity of the population. It is, therefore, essential that the food we consume is wholesome and safe. Unsafe food can lead to a large number of food-borne diseases. It is necessary that the food available is safe, hygienic, wholesome and its quality must be assured. Quality of foods can be defined as the ‘composite’ of those ‘characteristics’ that differentiate individuals units of a product and have significance in determining the degree of acceptability of that unit by the buyer. In general, the quality control is the maintenance of quality at levels and tolerance acceptable to the buyer, minimizing the cost for the vender. But, from the scientific angle the overall quality refer to technical, physical, chemical, microbiological, nutritional and sensory parameters to achieve the wholesome food. These quality factors depend on the specific attributes such as sensory properties, based on flavour, colour, aroma, taste, texture, quantitative properties viz. percentage of sugar, protein, fibre etc and hidden attributes like peroxide, free fatty acids, enzymes etc. Though quality attributes are many, not all need to be considered for a particular product. It is imported to determine how far relatively the factor is in relation to the total quality of the product.

Hence, the quality attributes of a particular is based on the composition of the product, expected deteriorate reaction, packaging used, shelf required and the type of the consumer i.e., deployed in terrain conditions or in peaceful situation. With the ultimate goal of protecting the consumer, quality standardization systems have come into force for regulating the gamut of operations in food manufacture. In a broader sense, food laws and Regulation cover the related acts affecting the marketing, production, labeling, food additives used, dietary supplements, enforcement of General Manufacturing Practice (GMP), Hazard analysis and critical Control Point (HACCP), federal laws and regulations, factory inspections and important-export inspections.

The food is considered as one of the essential for the maintenance of life. Manufacturing of the food product is not enough form the food industry. It is necessary that the food available is safe, hygienic; wholesomeness and its quality must be assured. The food industry is an important segment of industries in India and has its own peculiarities unlike other industries. Food processing industry has been recognized by government as a major sector of growth. It must be free from harmful additives, microbes and remain so for a period, it is intended to be consumed. Therefore, the methods employed in quality and food safety assurance programme within the food industry will vary considerably in accuracy and sophistication according to the type of process and size and nature of resources available. Since the international market has become demanding in terms of quality, safety and delivery, installation of Hazard Analysis Critical Control Point (HACCP) in food industry would provide a competitive edge to food supplies in the international market. Food control refers to all activities carried out to ensure the quality, safety and honest presentation of the food at all stages from primary production through processing and storage, to marketing and consumption. The term has been used to describe a total national effort involving an integrated approach between government and all segment and sectors of the food industry. Food control is linked to improvement in the health of the population, potential of a country’s economic development and reduction of spoilage and food losses.

A wide variety of quality determinants is employed, including size, colour, maturity and extent of blemishes. Quality is a measure of the degree of excellence or degree of acceptability by the consumer. The marketing of fresh fruit and vegetables is aimed eventually ay appealing to the consumer for whom tradition plays a major role in determining the acceptability of a food item. The eating habits of people are conservative. The increase of direct market from producer to supermarket chains is leading to the imposition of standards to predetermined specification by the supermarkets. Important factors in quality for the consumers are: appearance, including size, colour, shape, condition and absence of defects, texture, flavour and nutritional value. Quality is the ultimate criterion of the desirability of any food product to the consumer. The overall quality of food depends on the nutritional and other hidden attributes. Quality of foods can be defined as the ‘composite’ of the ‘characteristics’ that differentiate individual units of a product and have significance in determining the degree of acceptability of that unit by the buyer.

The word nutrition first appeared in 1551 and comes from the Latin word nutrire, meaning “to nourish.” Today, we define nutrition as the sum of all processes involved in how organisms obtain nutrients, metabolize them, and use them to support all of life’s processes. Nutritional science is the investigation of how an organism is nourished, and incorporates the study of how nourishment affects personal health, population health, and planetary health. Nutritional science covers a wide spectrum of disciplines. As a result, nutritional scientists can specialize in particular aspects of nutrition such as biology, physiology, immunology, biochemistry, education, psychology, sustainability, and sociology.

Disease is defined as any abnormal condition affecting the health of an organism, and is characterized by specific signs and symptoms. Signs refer to identifying characteristics of a disease such as swelling, weight loss, or fever. Symptoms are the features of a disease recognized by a patient and/or their doctor. Symptoms can include nausea, fatigue, irritability, and pain. Diseases are broadly categorized as resulting from pathogens (i.e., bacteria, viruses, fungi, and parasites), deficiencies, genetics, and physiological dysfunction. Diseases that primarily affect physical health are those that impair body structure (as is the case with osteoporosis), or functioning (as is the case with cardiovascular disease). Mental illnesses primarily affect mental and social well-being.

The foods we eat contain nutrients. Nutrients are substances required by the body to perform its basic functions. Nutrients must be obtained from diet, since the human body does not synthesize them. Nutrients are used to produce energy, detect and respond to environmental surroundings, move, excrete wastes, respire (breathe), grow, and reproduce. There are six classes of nutrients required for the body to function and maintain overall health. These are carbohydrates, lipids, proteins, water, vitamins, and minerals. Foods also contain non-nutrients that may be harmful (such as cholesterol, dyes, and preservatives) or beneficial (such as antioxidants).

The foods we eat contain nutrients. Nutrients are substances required by the body to perform its basic functions. Nutrients must be obtained from diet, since the human body does not synthesize them. Nutrients are used to produce energy, detect and respond to environmental surroundings, move, excrete wastes, respire (breathe), grow, and reproduce. There are six classes of nutrients required for the body to function and maintain overall health. These are carbohydrates, lipids, proteins, water, vitamins, and minerals. Foods also contain non-nutrients that may be harmful (such as cholesterol, dyes, and preservatives) or beneficial (such as antioxidants). Nutrients that are needed in large amounts are called macro-nutrients. There are three classes of macro-nutrients: carbohydrates, lipids, and proteins. These can be metabolically processed into cellular energy. Micro-nutrients are nutrients required by the body in lesser amounts, but are still essential for carrying out bodily functions. Micro-nutrients include all the essential minerals and vitamins. There are sixteen essential minerals and thirteen vitamins.

A forest is a large area dominated by trees. Many definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing and ecological function. Although a forest is usually defined by the presence of trees, under many definitions an area completely lacking trees may still be considered a forest if it grew trees in the past, will grow trees in the future, or was legally designated as a forest regardless of vegetation type. According to the Food and Agriculture Organization, forests covered four billion hectares or approximately 30% of the world’s land area in 2006. Forests are the dominant terrestrial ecosystem of earth, and are distributed around the globe. Forests account for 75% of the gross primary production of the earth’s biosphere, and contain 80% of the earth’s plant biomass.

DEVELOPMENT OF MODERN FORESTRY

Systematic management of forests for a sustainable yield of timber began in Portugal in the 13th century when Afonso III, the king of Portugal planted the trees to prevent coastal erosion and soil degradation, and as a sustainable source for timber used in naval construction. His successor Dom Dinis continued the practice and the forest exists still today. Forest management also started in Germany in the 14th century and in Japan in the 16th century. The practice of establishing tree plantations in the British Isles was promoted by John Evelyn during second half of the 17th century.

During the late 19th and early 20th centuries, forest preservation programmes were established in British India, the United States and Europe. Sir Dietrich Brandis is considered the father of tropical forestry. He brought European concepts and practices to the tropical and semi-arid climate zones. The enactment and evolution of forest laws and binding regulations occurred in most Western nations in the 20th century in response to growing conservation concerns. Tropical forestry is a separate branch of forestry which deals mainly with equatorial forests that yield woods such as teak and mahogany. One of the applications of modern forestry is reforestation, in which trees are planted and tended in a given area.

Agroforestry is a new name for a set of old practices. The general concept of agroforestry is to integrate trees and agriculture so as to create a more diversified landscape, while providing the producers with new environmental and economic benefits. In other words, agroforestry is a method of farming that allows trees and shrubs to grow along with crops and/or livestock, therefore blending agriculture and forestry in the same production system. In fact, man’s association with forest is much older than with agriculture. First man was a food gatherer and hunter in forests. Then he realized that the seeds of the fruits he collected germinated, grew into plants and bore the fruits again and thus man started to cultivate foods. Man’s desire to live in a community created settled agriculture.

The pressure on the agricultural lands has increased manifolds due to the increasing population, expansion of urban area and the industrialization process. The environment has also been disturbed. Soil is losing its productivity and the biodiversity is threatened. Farming community is trying all means to increase the land productivity. Chemical fertilizers and pesticides are applied in higher proportion, causing environmental pollution hazards. Under all these circumstances agroforestry has shown that besides sustainable agriculture it can also help promote a better environment. Trees have always played an important role in mankind’s survival. This relatively young science known as agroforestry was brought from the realm of indigenous knowledge into the forefront of agricultural research four decades ago and was promoted widely as a sustainability-enhancing practice that combines the best attributes of forestry and agriculture.

Trees have been used in cropping systems since the beginning of agriculture. Throughout the world, at one period or another in its history, it has been the practice to cultivate tree species and agricultural crops in intimate combination. In the tropics, human beings underwent a transition from hunting/gathering to the use of domesticated plants and livestock. As a part of the process, they cut down trees, cleared the debris by burning and sowed crops in the ash-enriched soil. It was the ‘slash-and-burn’ agriculture, a primary forerunner of the present-day agroforestry and a practice that might have originated in the Neolithic period, around 7000 BC.

There are innumerable examples of traditional land-use practices involving combined production of trees and agricultural species on the same piece of land in many parts of the world. Trees were an integral part of these farming systems and they were deliberately retained on farmlands to support agriculture. These practices are now known as agroforestry. However, the ultimate objective of these practices was not tree production but food production.

The words ‘system’, ‘sub-system’ & ‘practice’ are commonly used in agroforestry literature. In a broad sense, a system is defined as a group of associated elements forming a unified whole and working together in a well-defined regular relation for a common goal. An agroforestry system refers to a type of agroforestry land-use that extends over a locality to the extent of forming a land utilization type of the locality. Sub-system and practice are lower-order terms in the hierarchy with lesser magnitudes of role, content and complexity. However, these terms are used loosely, and almost synonymously.

Classification of agroforestry systems is necessary in order to understand and provide a practical framework for evaluating systems and developing action plans for their improvement. Any classification scheme should satisfy the following criteria (Nair, 2008).

The word ‘social forestry’ was coined by Westoby and used in the ninth Commonwealth Forestry Conference at New Delhi in 1968. In India the term was first used by the National Commission on Agriculture, Government of India in 1976, to denote tree raising programmes to supply firewood, small timber and minor forest products to rural population. Prasad (1985) defined social forestry as forestry outside the conventional forests which primarily aims at providing continuous flow of goods and services for the benefit of people. This implies that the production of forest goods for fulfilling the needs of the local people is social forestry. Thus, conceptually it deals with the people to produce goods such as fuel, fodder, small timber, etc. to meet the needs of local community particularly the underprivileged section (Shah, 1988).

Urban forestry is not a new concept, but it is one which appears to have growing potential. With increasing urbanization in the 20th century, the incorporation of trees into urban settlements has also increased. The management of all trees within the urban area is considered a distinct discipline of forestry. Urban forestry was conceptualized in the late 1960s in North America, and grew out of what was initially termed environmental forestry. Trees and urban forests can make our cities cleaner, cooler, greener, safer, healthier, happier and nice places to live.

Management approaches to soil, including problems of soil degradation and low soil fertility, have recently undergone major changes. The earlier concept was to concentrate on achieving high levels of production from the more fertile areas, leaving the marginal lands for extensive use only. Steeply sloping and highly drought-prone areas were mostly left without any cultivation as production from these areas was hardly cost effective. Soil constraints were to be overcome by inputs like improved crop varieties, fertilizers, chemical control of pests and diseases, and the use of irrigation.

The approach of use of newly developed high yielding crop varieties, improved agronomic management practices, use of chemical fertilizers, efficient water management and timely plant protection measures has been successful in achieving large increases in crop productivity in recent years. On the other hand, continuous application of fertilizers at higher rates leads to environmental problems. Yield responses to fertilizers have declined because of soil physical degradation and micronutrient deficiencies. Above all, large numbers of poor farmers simply can neither afford high levels of fertilizers and other purchased inputs, nor do they have the capital to take on the risk involved in their use. Increasing the area under irrigation has also run into severe constraints in the form of limits to available freshwater resources.

Agroforestry systems are not simply systems where trees and crops or animals give useful products to the farmers, rather systems where trees and crops and/ or animals interact. Interaction literally means influence or mutual or reciprocal action. So, component interaction refers to the influence of one component of a system on the performance of other component as well as the system as a whole.

In agroforestry systems, trees are grown in close proximity to crops and pasture. Their performance would largely depend on their ability to share various growth resources in a given environmental situation. Various interactions take place between the woody trees and herbaceous plants (crops or pastures) which is referred to as tree-crop interface. These interactions take place through the media of soil and microclimate and may exert favourable or adverse effects on the crop. Study of interaction helps to know how the components of agroforestry utilize and share the resources of the environment, and how the growth and development of any of the components will influence the others. Interaction occurs both above and below the ground and includes a complex set of interactions relating to radiation exchange, the water balance, nutrient budget and cycling, shelter and other microclimatic modifications.

The success of an agroforestry system relies heavily on exploitation of the component interactions. In an ideal relationship, production of trees as well as crops or grasses in combination could be comparable to their sole performance. Agroforestry could be even more advantageous if the production of associated components is increased due to influence of trees. This is possible because trees are capable of improving productivity of soil in many ways. A large number of trees are known to fix nitrogen symbiotically. Nevertheless, instances of crop inhibition in association of trees are not uncommon. Such inhibitions are primarily caused by shade effect as well as competition for below-ground resources such as nutrients and water. In some cases, inhibitory effect may also result from allelochemicals secreted by some of the tree species.

Farmers have been growing trees for different purposes for thousands of years. Tree species that are grown to provide more than one significant function are called multipurpose trees. These functions may be productive such as producing fuelwood, timber, fibre, fodder, food, medicine, etc. and/or protective such as soil conservation, shade, shelterbelt, microclimate amelioration, land sustainability, biodiversity preservation, etc. All trees are multipurpose; some, however, are more multipurpose than others. Tree species can be multipurpose in two ways.

Agroforestry is a land use system that involves two or more plant species at least one of which must be a woody perennial. When perennial woody and herbaceous components are grown together on the same piece of land their performance would largely depend on their ability to share various growth resources in a given environmental situation. Due to difference in growth pattern and resource requirement of the components in agroforestry situation, a close interactive relation is obvious. Thus, careful management practices for the components are required to establish a successful agroforestry system. The characteristics of the trees and crops, and their interactions, can be modified with good management practices in order to take advantage of the positive characteristics and minimize the effects of the negative ones. Effective and efficient agroforestry management may be divided into two groups; tree management and agricultural crop management.

FACTORS AFFECTING THE SELECTION OF TREE SPECIES

Trees in an agroforestry system contribute significantly to the total output of the system and therefore, success of the system depends on the selection of the tree species. The following factors are to be considered to choose the best tree species for the agroforestry systems in a particular site.

Ecology of a place is influenced by a number of biotic and abiotic factors. An agroecological zone is broadly homogeneous in climatic and edaphic factors, but not necessarily contiguous, where a specific crop exhibits roughly the same biological expression. On the other hand, the characteristics of an agroecological zone influence the crops and cropping patterns of the zone. Thus, there are considerable variations in the types and management practices of agroforestry systems being followed in different agroecological zones.

AGROFORESTRY FOR HUMID AND SUBHUMID TROPICS

Humid and subhumid tropical regions have much variation in biological, social and economic parameters. The characteristics of humid tropics include high mean annual rainfall of more than 1500 mm, dry season of less than four months in a year and mean annual temperature of more than 22° C. Rainfall usually exceeds the evapotranspiration. However, demographic pressure has caused excessive deforestation and overgrazing which developed soil related problems like low soil fertility, low organic matter, high acidity and high rainfall erosivity. The agroforestry practices designed for this region should aim for improved fallows, soil fertility improvement and conservation, food production, etc. Thus, the common agroforestry systems in this zone are taungya, homegardens, alley cropping, plantation-crop combination, windbreaks, silvipastoral systems and various intercropping systems. Shifting cultivation is a common practice in tropics which should be discouraged as it causes environmental degradation and ecological imbalance, soil erosion and soil nutrient loss.

A watershed is a geohydrological unit or all the land and water area bounded by a divide which contributes runoff to a common point. Watershed is considered to be synonymous with ‘catchment basin’ and ‘drainage basin’. In watershed management approach, development is not only confined to agricultural lands but also covers the area, starting from the highest point of the land to the outlet of the natural stream. Watershed management becomes increasingly important as a way to improve livelihood of people while conserving and regenerating their natural resources.

Watershed management is the process of creating and implementing plans, programmes and projects to sustain and enhance watershed functions that affect the plant, animal and human communities within a watershed boundary. It implies the judicious use of all the resources, i.e., land, water and vegetation in an area to prevent soil erosion, improve water availability and increase food, fodder, fuel and timber on sustained basis.

India shares 17.4% of the world population, while its land is only 2.4% of the total geographical area of the world. Naturally, the pressure on the land is often beyond its carrying capacity. Therefore, the productive lands, especially the farmlands in India are in the constant process of various degrees of degradation and are fast turning into wastelands. At present, approximately 55.76 million hectare area of the land is lying as wastelands in India. Out of these lands, about 50% lands are such non-forest lands, which can be made fertile again if treated properly. In the last 60 years India’s lush green village forests and woodlots have been deforested to the maximum. To restore this ecological imbalance by developing the degraded non-forest wastelands, Government of India had created the Department of Wasteland Development during July, 1992 under the Ministry of Rural Development, which has been subsequently reorganized and renamed Department of Land Resources, with a broader mandate.

National Wasteland Development Board was established in 1985 mainly to tackle the problem of degradation of lands, restoration of ecology and to meet the growing demands of fuelwood and fodder at the national level. The Board was reconstituted in August, 1992 and was made responsible for development of wastelands mainly in non-forest areas in totality by involving local people at every stage of development. It aims at creating a scenario where the Government acts as a facilitator and the people at the grass root level become the real executioner of the programme. The degradation of environment in the fragile Indian subtropical ecosystem is basically attributed to the following factors.

Human societies over the ages have depleted natural resources in different ways and degraded their local environments. Indiscriminate cutting down of trees and accelerating the construction works lead to global warming and climate change. Climate scientists believe that human-induced deforestation is responsible for 18-25% of climate change. Accumulation of greenhouse gases in the lower atmosphere is the main cause of global climate change. The concentration of these gases in the earth’s atmosphere is increasing, mainly due to deforestation and the combustion of fossil fuels which release carbon dioxide.

The earth receives heat energy constantly from the sun through radiation. Some of the heat is absorbed and some is reflected. Carbon dioxide works like an invisible blanket that wraps around the earth and traps the heat inside, similar to the function of a greenhouse. A greenhouse is a structure that is used in colder climates to grow plants. Even when outside temperatures drop below freezing point, greenhouses are still warm enough inside to grow plants. Greenhouses are made of glass, which allows solar radiation to enter. The heat is trapped inside the greenhouse, allowing plants to grow all the year round. Increasing concentrations of carbon dioxide in the earth’s atmosphere insulate it like a greenhouse, leading to a gradual warming of the earth’s atmosphere. Carbon dioxide is the major greenhouse gas, but there are others as well, including methane and nitrous oxide.

Mitigation means addressing the causes of climate change, while adaptation attempts to tackle its effects. The Intergovernmental Panel on Climate Change defines mitigation as an anthropogenic intervention to reduce the sources or enhance the sinks of greenhouse gases and adaptation as the adjustment in natural or human systems to a new or changing environment (IPCC, 2007).

Greenhouse gas emission is likely to rise by 25-90% by 2030 relative to 2000 and the earth could warm by 3° C at the end of this century. Even with a temperature rise of 1-2.5° C, the Intergovernmental Panel on Climate Change predict serious disastrous effects, including reduction in crop yields in tropical and subtropical areas leading to increased risk of food shortage, spread of climate responsive diseases such as malaria, and an increased risk of extinction of 20-30% of all biodiversity present on earth (IPCC, 2007). Carbon dioxide is the most important among all greenhouse gases. Carbon sequestration may be defined as the process of removing C from the atmosphere and depositing it in a reservoir. It entails the transfer of atmospheric carbon dioxide, and its secure storage in long-lived pools (UNFCCC, 2007).

From the agroforestry point of view, carbon sequestration involves primarily the uptake of atmospheric CO₂ during photosynthesis and transfer of fixed carbon into vegetation and soil pools for ‘secure’ storage. It occurs in two major segments of agroforestry systems; aboveground and belowground. The total amount sequestered in each part differs greatly depending on a number of factors including the region, the type of system, site quality, and previous land-use (Nair, 2012). On average, the soil and aboveground parts are estimated to hold major portions, roughly 60 and 30%, respectively, of the total carbon stored in tree-based land-use systems (Lal, 2010). Sequestering CO₂ from atmosphere through natural techniques such as afforestation, reforestation, natural regeneration of forests and the adaptive agriculture is more economically and ecologically sound in increasing the carbon storage capacity of the terrestrial ecosystems (Dhyani, 2014). Although carbon sequestration through afforestation and reforestation of degraded natural forests has long been considered useful in climate change mitigation, agroforestry offers some distinct advantages (Murthy et al., 2013). The carbon in the aboveground and belowground biomass in an agroforestry system is generally much higher than the equivalent land use without trees. An agroforestry system has higher carbon sequestration potential than pastures or field crops (Kirby and Potvin, 2007).

In agroforestry systems the various components like tree, crop and pasture exist in different proportions and orientations. It is difficult to find out which agroforestry system is the best suited for a given land situation. Similarly, it is to be decided which technologies are required for refinement and improvement of the existing agroforestry practices. But without sufficient knowledge of the existing system in a particular land situation, it is very difficult to set the research priorities for modification and development of this system.

Diagnosis and Design (D & D) is a systematic and objective methodology developed by International Centre for Research in Agroforestry (ICRAF) to initiate, monitor and evaluate agroforestry programmes. D & D is based on the philosophy that knowledge of the existing situation (diagnosis) is essential to plan and evaluate (design) meaningful and effective programmes in agroforestry research for development. The methodology plays a strategic role in all the phases of the agroforestry research process. D & D in agroforestry is unique and it has been specially developed for the following purposes.

Agroforestry systems are more complex than the agricultural systems. The long-term nature of trials involving woody species and the varying objectives of agroforestry trials demand that adequate caution be exercised in their design. Several characteristics of the trees like slow growth, long-term effects on their surroundings, long life, age of trees, the area over which the influence of trees extend, etc. complicate the issue of designing experiments for these systems. Agroforestry experiments are often established on marginal sites which include sloping lands, and sites with infertile and degraded soils. It is thus difficult to find homogeneous sites of such problem areas, especially sloping lands where plots along contour lines are long and linear. Germplasm of many agroforestry tree species are usually collected from different origins which lack uniformity. Therefore, experimental materials in an agroforestry experiment may not be of uniform quality.

There are several features of agroforestry systems that require some modification of the methods usually used in agricultural experiments. Important issues related to agroforestry experiments include

Economic analysis provides a rational basis for making decisions in allocating scare resources among various options to achieve competing goals. If resources were not limiting, there would be no need for economic consideration. Some important basic principles of economic analysis are outlined below.

PRINCIPLES OF ECONOMIC ANALYSIS

Optimization criteria

The additional return obtained from using one additional unit of an input should be considered to optimize net income from several possible production options. If option ‘x’ gives a higher return to land than other options, then additional units of land should be allocated to option ‘x’.

Agricultural extension is a term that has long been used to describe a non-formal educational system aimed at improving the livelihood of farmers. Extension education aims at three main types of behavioural changes in relation to knowledge (things known), attitudes (things felt) and skills (how to implement the things). This can be achieved through persuasion and motivation for the changes. The core activities in extension are education and training. Extension is now being regarded as a much wider task of integrating indigenous and new skills and techniques, derived from study or research, into an overall framework of discussion and cooperation between the people and the extension organisation. The extension worker is primarily engaged in the ‘selling’ of ideas to bring about changes in the knowledge, attitudes and skills of the individual. Functions of extension in a broader sense include