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Nitrogen is the most important element on which depends growth and productivity of plants. It is also the most abundant molecule in the atmosphere (80%), yet it cannot be utilized by plants. The plant utilizable form of nitrogen is either, its most oxidized form, the nitrates or the most reduced state, the ammonia.  The indiscriminate use of nitrogenous fertilizers amounts to depletion of non-renewable fossil fuels used in fertilizer production. Sustainable agriculture depends largely on renewable resources and on-farm nitrogen contributions are achieved largely through biological nitrogen fixation (BNF), which helps in maintaining and/or improving soil fertility by using atmospheric nitrogen. Annually BNF is estimated to be around 175 million tonnes of which close to 79% is accounted for by terrestrial fixation.

The term soil refers to the outer, loose material of the earth’s surface, a layer distinctly different from the underlying parent rock. A number of features characterize this region of the earth’s crust. It is the natural medium, which supports plant growth. It provides the physical support needed for the root system and also supplies nutrients needed for plant growth. It is a perennial source of organic matter. It supports a vast population of microorganisms.

Biotechnology plays a very important role in agriculture as a result of its ability to modify microorganisms, plants, animals, and agricultural processes. The umbrella of microbial technology in agriculture covers numerous scientific activities, ranging from production of biofertilizers to that of microbial pesticides; from biological nitrogen fixation to lignocellulose degradation; from production of biomass and biofuels to transgenic plants. Terrestrial ecosystem contains an important dynamic living matrix termed soil, which is critical for agricultural production and food security. Soil forms the medium for growth and maintenance of a variety of plant species. Soil is considered a store house of microbial activity, though the space occupied by living microorganisms is estimated to be less than 5% of total space.

Introduction

Spices hold a special place in world trade and were a catalyst in many historical events, discoveries, wars and inventions. It has even been cited as an important element in the spread of knowledge and culture. Spices are non-leafy parts of plants used as a flavoring or seasoning. Asia is known as ‘Land of Spices’ as it is the place of origin, production, consumption and export of most spices. Out of the world’s 70 plant species grown as spices, 13 are considered major spices produced in Asia. Spices had many uses, from adding flavour to food to medicinal properties, but only grew in a few places. In the last decade, the annual average growth in spice production was 4.3% and trade in spices grew at an average of 5.8% /year. More sophisticated consumers, health-conscious eating habits (but also the rise in the amount of processed foods that use herbs and spices as inputs), rising incomes, increased world trade and globalisation are driving this new era of profitability. Spices are ideal commodities for international trade. They are normally exported in raw or dried form and are usually easy to store and transport. Consequently they do not need expensive infrastructure such as cold chain management or advanced storage facilities and they are not particularly time sensitive. In addition, they are recognised as high value products that can be produced relatively easily on small farms and do not require investments in advanced technology and machinery.

Introduction

Plantation crops are high value industrial crops with great economic importance and play vital role in trade. It contributes to environment protection and sustains a large number of agrobased industries. It has great potential for utilization of waste lands in varied agro-ecosystems like rainfed, dryland, hilly, arid and coastal, providing higher employment opportunities, nutritional security, eco-friendly, high potential for foreign exchange earnings and above all providing livelihood security to people. They contribute 25% of AGDP. Major plantation crops grown in India are coconut,cardamom,cinchona, arecanut, oilpalm, cashew, palmyra, rubber, cocoa, tea and coffee. These crops grown between 20° N and 20° S of equator occupy nearly 3.2 million ha with a production of 9.8 million tonnes. All these crops are perennial in nature and demand  labour round the year. All plantation crops enter international trade and all of them have a long juvenile period. Coconut, arecanut and cashew are cultivated by individual land  owners who are not organized to the same extent as  planters of tea, coffee and rubber.

Introduction

Flowers are the most fascinating objects in the world and many poems are written glorifying them. They are associated with mankind from the dawn of civilization. Flowers are an integral part of our day to day life and they find a place in worshiping, religious and social functions, wedding, interior decoration and self adornment. Flowers are used to convey the human feelings. To say it with flowers is very common in western culture. Emergence of a strong middle class and changing life style has created a great demand for cut flowers in India.

Introduction

India has a long history in the cultivation of vegetable crops and it sustains the livelihood of a large section of population directly or indirectly. Vegetable crops offer high returns,  have a potential to alleviate the poverty of people, provide nutritional security and essential raw materials for agro industries. These crops also offer greater rural employment opportunity and have high potential for foreign exchange earning. India bestowed with varied soil and high climatic conditions has excellent potential for growing both tropical and temperate vegetables. India is the second largest producer of vegetables in the world after China. The total area under vegetables is estimated 5.9 million ha which contributes more than 2.5% of total cropped area. The production is estimated  90.83 milion tonnes. China having a production of about 278.59 million tonnes  is the largest producer of vegetable crops in the world. The annual growth rate in vegetables is of the order of 2.6%. Potato, brinjal, tomato, chilli, cabbage, onion, cauliflower,okra and peas are grown on commercial scale. West Bengal, Uttar Predesh, Bihar, Orissa and Karnataka are the leading vegetable producing states. Maharashtra, Gujarat, Karnataka, Uttar Pradesh and Andra Pradesh are the leading states in onion production where as West Bengal, Uttar Predesh and Bihar are the leading potato producing states. Bengal, Orissa, Bihar and Assam are the leading brinjal producing states.

Introduction

Fruits are undoubtedly God’s gift to mankind. Fruits are protective foods as they contain vitamins, minerals and enzymes, necessary for better functioning of human body and for fighting diseases. History of fruits is as old as that of Adam and Eve who ate the forbidden apple. Date palm seems to be the earliest fruit cultivated by man as early as 7000 B.C. Pomegranate is also one of the oldest fruits which was under cultivation as early as 3500 B.C. During ancient times, monks survived solely on fruits and milk giving an indication about importance of fruits and antiquity of fruits in India. India is the place of origin of mango, banana, phalsa, jack fruit, bael, aonla and a few citrus fruits whereas all other fruits are introduced from foreign countries. Litchi, loquat, persimmon, peach and sweet orange are from China; papaya, guava, sapota, avocado, custard apple and pineapple are from tropical America; and apple, plum, pear, date palm, mangosteen, strawberry, cherry, almond, walnut, apricot, grape and pomegranate are from the Central Asiatic Regions.

Aconites, the tuberous roots of which contain highly toxic alkaloids, are deadly poisons. In small doses, aconites are beneficial in nasal catarrh, sore throat, gibbous, paralysis and chronic fevers. Aconitum is a genus of perennial, erect or rarely twining herbs distributed over North temperate regions of world. The mountains of Eastern Asia form the primary centre, presenting the greatest diversity of genus. About 28 species are reported from India, mostly confined to alpine and subalpine belts of Himalayas. Of the Aconitum spp. occurring in India, roots of nine species are obtained in Indian market. In fact, aconite sold in Indian market is a mixture of 304 species. Still, A. ferox, known as Indian Aconite, is considered the most important.

A. ferox is a perennial herb with tuberous roots. Roots are paired, daughter tuber, ovoid oblong to ellipsoid, with filiform root fibres. Leaves are scattered, orbicular-cordate to reniform, palmately 5 lobed, resembling melon leaves. Petioles are pubescent. Flowers are pale dirty blue, borne in a dense terminal raceme, 10-25 cm long. Follicles are oblong with long, obovoid winged seeds.

Aloe, known for laxative property is one of the old natural remedies that have emerged as modern miracle drug. Popularly known as ‘nature’s sun screen’ has growing use as skin tonic in cosmetic industry and as a nutraceutical. Aloes are also quite popular among succulent ornamental plants because of their stiff, harsh and rugged habit and are commonly grown in deserts and other dry situations. Genus Aloe is indigenous to African continent and Mediterranean countries such as Greece and Southern Italy, and got naturalized in arid tracts of India. In India, Aloe barbadensis is cultivated on a small scale in Rajastan, Andhra Pradesh and Gujarat (CSIR, 1998).

Botany

Genus Aloe belonging to Liliaceae comprises 275 species distributed in Africa, Asia and America. Forty-two species belong to Madagascar region, 12-15 to Arabian Peninsula and rest are distributed over tropical South Africa. Aloe barbadensis, A. ferox and A. arborescens are used as herbal drugs. In India, only four species occur and of these, Aloe barbadensis is the most widely naturalized species. These taxa comprise several varieties viz., officinalis, chinensis, littoralis and they cross freely and several intermediary forms occur in semi wild state.

Good Agricultural Practices

Guidelines for Good Agricultural Practices of Medicinal and Aromatic Plants is intended to apply to the growing and primary processing of all such plants traded and used in food, feed, pharmaceutical, flavouring and perfume industries. The main aim is to ensure that the raw material meets the demands of the consumer and maintains standards of the highest purity. Important aspects are that, these are produced hygienically, in order to reduce microbial load to a minimum, and are produced with care, so that the negative impacts affecting plant during cultivation, processing and storage can be minimised. The guidelines provide guidance for producers to reduce raw material contamination to the lowest level. This document can be used in bilateral relationship between the supplier and the customer and the products documentation is regarded confidentiall (EUROPAM).

Medicinal plants and their various products are extensively utilized not only in traditional systems of medicine but also in modern medicine throughout the world. In recent times, they have also attracted attention of scientists encompassing various disciplines of medicine and biotechnology for search of new drug molecules and modern drug development. Although several research strategies are followed for drug development only the traditional, empirical and molecular methods/strategies are mostly applied. There is also need of scientific validation for safety, efficacy and rational use of traditional form of medicine along with development of standards for identity, purity and strength (Singh and Bagchi, 2002).

Approaches of Drug Developement

Following approaches are generally employed to discover and invent new therapeutic agents from plants viz. screening of plant materials, identification of active constituents, pharmacological and clinical evaluation and drug design.

Phytochemistry

Pytochemistry is concerned with enormous variety of organic substances that are elaborated and accumulated by plants and deals with chemical structures of these substances and biosynthesis, and their natural distribution and biological function. Chemical constituents of plants can be classified in different ways. Based on biosynthetic origin, solubility properties and presence of certain key functional groups, it is classified as phenolic compounds, substances that are readily recognized by their hydrophilic nature and by their common origin from aromatic precursor shikimic acid. Terpenoids share lipid properties and a biosynthetic origin from isopentenyl pyrophosphate (Fig. 1). Organic acids, lipids, alkenes and related hydrocarbons, polyacetylenes and sulphur compounds are derived biosynthetically from acetate. Nitrogen compounds of plants like amino acids, amines, alkaloids, cynogenic glycosides, indoles, purines, pyramidines and cytokinins and chlorophyll are basic substances recognized by their positive responses to either ninhydrin or Dragendorff reagent. Monosaccharides, oligosaccharides, sugar alcohols and cyclitols are water-soluble carbohydrates and their derivatives. Macromolecules of plants such as nucleic acids, proteins and polysaccharides are easily separated from other constituents by their high molecular weights (Harborne, 1984). Some of the therapeutically active compounds are discussed below:

Plants have been a major source of therapeutic agents since time immemorial. The increasing acceptance of traditional herbal systems of medicine, like Ayurveda, within India and outside has resulted in the revival of ancient traditions of medicine. Medicinal plants and their derivatives are thus looked upon not only as a source of affordable healthcare but also as an important commodity item of international trade and commerce. As per World Health Organization estimates, traditional medicines, mostly plant drugs, cater to the health needs of nearly 80% of the world population. The medicinal plant related trade is growing rapidly every year due to the growing recognition of natural products being non-narcotic, with relatively less side effects and being easily available at affordable costs.

In India, medicinal plant sector has traditionally occupied an important position in the socio-economic, cultural and spiritual arena of rural and tribal lives. About 8000 flowering plants, 650 lichens, 650 algae, 200 pteridophytes and 150 bryophytes are attributed with medicinal properties. The Indian coded systems encompasses a large number of treaties on recognized systems of medicine viz. Ayurveda, Unani and Siddha. The Ayurvedic system of medicine, which cater to the health needs of a major segment of population currently utilizes as many as 1000 single drugs and over 8000 compound formulations of recognized merit. Other systems of medicine viz. Siddha, Unani and Amchi (Tibetan) systems of medicine together utilize about 1800-1900 medicinal species. Many medicinal plants are the source of clinically useful prescription drugs being used in modern systems of medicine. Also incredible knowledge on phyto medicine is acquired in non-coded form by tribals and rural community, as is clear from evidences related to folklore medicine. Recognizing their importance, medicinal plant sector has been identified as one of the key areas by the Government of India and the Department of Indian System of Medicine and Homeopathy.

Agronomic Research

Statistical tools are used in all branch of agriculture. It is mainly used for efficient planning of experiments and for interpreting experimental data. A good researcher should be aware of statistical techniques, which helps not only summarization of data but also interpretation of data.

10.1. Parameters Used in Statistics

Population

The aggregate or totality of all possible objects possessing the specified characteristic is called a population. Thus, a population may consist of all plants in a plot or field.

Sample

A portion of the population is known as sample. For statistical inferences about a population from a sample, it is essential that the samples are representative of the population.

Cost of Cultivation

The expenditure incurred from sowing to harvest including the field preparation can be worked out and expressed in Rs. ha^-1.

Gross Return

Total income obtained from multiplication of unit cost of main product as well as byproducts and its total yield and expressed in Rs. ha^-1.

Net Return

Net return is obtained by subtracting cost of cultivation from gross return and expressed in Rs. ha^-1.

Net return = Gross return – total cost of cultivation

The thrust of Indian Agriculture in the post green revolution period was an enhancing agricultural productivity through sustainable practices. In order to achieve its, the government of India implemented a national level programme for the development of rainfed areas through the watershed approach. A watershed is a community-based programmes that is organized in a specifically earmarked area with a defined time frame and focuses on a wide range of issues and activities for integrated development of the village. The main focus is laid on water, food and fodder security and employment generation

The watershed approach aimed at augmentation and stabilization of production and productivity, minimizing ecological degradation, reduction in regional disparity, opening up of greater opportunities for employment of rural poor in the rainfed areas. A similar approach has been adopted for developing the more resource poor areas — drought prone, desert and wastelands — and to provide sustainable means of livelihoods to the rural poor in these areas. Promotion on the economic development of the village community, optimum utilization of the watershed’s natural resources like land, water, vegetation, employment generation and development of the human and other economic resources of the village and encourage restoration of ecological balance in the village are the main objectives of watershed development programmes.

Comparison of different cropping systems with reference to land use and yield advantages is possible through various efficiency indices. The various cropping and farming systems practiced in an area have to be properly evaluated to decide their suitability and relative advantages. The comparisons can be made with reference to many factors viz., yield, monetary, water use efficiency, nutrient use efficiency, total dry matter production, intensity of land use etc., The cropping as well as farming systems research are being perused at national level with major focus for identification of location specific efficient systems since 1990. However, on perusal of research publications we find that the data of cropping systems are interpreted in different ways with major focus only on production and net return on hectare basis. In fact, these two aspects are not the indicator of the efficiency of a particular system. Many advances have been made in recent years to identify the efficient system for a particular location. Some of the methodologies, which are of concern to crop scientists in general and agronomists in particular, are highlighted here for ready reference to the researchers, agronomists and crop planners. Different indicators of system efficiency are as follows (Gangwar et al., 2003).

Weed management practices are evaluated for its efficiency in terms of effective control of weeds and economics of control measures through various indices under sole crop situation as well as intercrop situation.

6.1. Indices for Sole Crop Situation

The absolute effect of particular method or a chemical in reducing the weed competitions and increasing the crop productivity are measured effectively by various indices. The comparisons of weed control methods are usually based on the yield, weed population and weed dry matter from the control as well as treated plots.

Agricultural water consumes about 85% of the available water. The future hopes to solve world’s food problem lies in irrigation development. Considering the need of efficient management of water, which is crucial at this point understanding of different efficiencies of the irrigation related experiments or projects, is necessary. Irrigation efficiency is used to evaluate how effectively the available water is used in crop production. Water is conveyed through canal system, watercourses and channels to crop fields. Irrigation is applied to store water in the effective root zone of soil for use of crops. A considerable loss occurs after its diversion from sources to its actual use by crops. The extent of water loss in the process decides the irrigation efficiency. Irrigation efficiency declines as the water loss increases. A high efficiency of an irrigation project is always desirable. The efficiency may be estimated for various operations beginning from diversion of water to its actual use by crops, uniformity in its distribution in the root zone, its use for crop productivity, economics and so on.