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One of the attractions of ornamental fish keeping is to multiply the fishes in captivity. Although techniques used for ornamental fish breeding are not much difficult, the breeding methods for specific ornamental fish species are closely guarded secrets. Farmers have operated almost entirely on their own, developing their own methods and rely on many years of experimentation. In India, the most important breeding centres for ornamental species are located in Kolkata, Mumbai, Chennai and Kochi. Ornamental fishes are broadly classified into two groups based on their breeding methods- Egg layer or oviparous and live bearer or viviparous species. Oviparous fishes lay floating, adhesive or non-adhesive eggs that may be scattered, laid in bubble nests or deposited on substrates or in shallow pits. The breeding and rearing of live bearers are easier than egg layers, which begin with handling the live bearers.

The indigenous ornamental fish which are very popular overseas, are being harvested from the wild and exported. This in the long run, may lead to depletion of stock due to over harvesting of our valued native fish species. Hence, breeding of native fish species is also equally important for a sustainable trade of ornamental fishery and to conserve the natural stock. Some fishes breed naturally with ease, whereas others are bred by artificial techniques like hand stripping and hypophysation. In nature, the fishes are stimulated by changes in environmental factors. These conditions can be simulated to some extent in the aquaria by providing specific biological requirements for spawning.

I. Breeding of Zebra danio (Brachydanio rerio)

Brachydanio rerio is commonly known as zebra danio. The zebra danio, as the name implies, is characterized by a number of bright blue or purple horizontal lines, which run from the head to the caudal fin. This pattern is repeated in the anal and caudal fins too. The flanks have prussian blue colouration and operculum has golden blotches. The dorsal fin of this species has an olive yellow base and there are blue gold markings on the anal fin.

As the ornamental fish industry expands throughout the world, genetic considerations have become more important in terms of production, sustainability and conservation. Genetic technologies are now being applied to increase food production in aquaculture through traditional and modern breeding programmes. Genetic markers can help to manage capture fisheries and distinguish farmed from wild stocks in mixed fisheries. Genetic technologies are also now finding application in post-harvest and trade to assist in product identification and traceability. Genetic improvement of fish has considerably increased the fish production from aquaculture. It includes selective breeding, hybridization, polyploidy, gene and nuclear engineering. For any genetic selection programme, induced breeding is the basic and initial step. Intensive selective breeding is practiced with various species of fish in perfecting appearance, shape and color so that new strains are produced.

Domestication

Most of the fish being widely grown in captivity are domesticated to some extent, but there are very few which have undergone genetic improvement. Just as terrestrial livestock and crops are bred to be not only productive, but productive in convenient proximity to humans, aquatic plants and animals are now undergoing these same pressures.

In comparison to agriculture crops, fruit plants and animals, aquaculture is much behind with regard to the domestication of the fish, especially ornamental fish. Never the less, a good number of ornamental fish have been domesticated which can be considered for selective breeding to improve their traits. The available technologies and tools could be used to remarkably speed up domestication and genetic improvement process.

Domestication implies much more than merely keeping wild animals in farms or homes. Domestication is a very long process, during which captive individuals become more adapted to captive environments. Domestication leads to permanent genetic modifications of a bred lin-eage, while taming or keeping wild fish in captive conditions is only conditioned behavioral modification of individuals. The entire life cycle of the domesticated fish species must be fully closed in captivity. Once full life cycle is completed in captivity, the process of domestication can proceed further.

The first truly domesticated fish species was certainly the goldfish, for which the domestication was initiated by the Chinese about 1500-2000 years ago.

Ornamental fishes are very prone to diseases due to their captive habitat. Fish health management is an important issue of concern at all the ornamental fish production facility. Proper water quality is required to be maintained in the aquarium for the good health of the fish. However, the chance of infection in these fishes is very high. Many limiting factors viz. water quality, over crowding, nutritionally imbalance food, rapid fluctuation in water temperature, lack of oxygen or poor husbandry practices influence the health status of the stock. The symptoms/signs indicate whether the fish is suffering from a particular disease or not. If the fish are observed to be swimming actively and there is no noticeable abnormality in the behaviour, it means there is nothing to worry about the health of the fish in the aquarium. On the other hand, diseased fish may look off colour, restless and/or behave erratically. In such a situation, the fish should be closely observed for visible infection and remedial measures should be taken immediately. Stock improvement in terms of disease prevention must be a top priority issue. In order to achieve healthy fish species, it is necessary to have a health management protocols in every farming practices.

Ornamental fish breeding and trade provide excellent opportunities for employment and income generation. One of the most critical determinants of the success of the trade is the problem of delivering a quality product to the market. The know-how of collection, critical handling, packaging methods are essential for serving the successful transport of live tropical fish to their final destination. However, a major impediment in expanding the trade of indigenous fishes is the poor roads/communication from most of the collection/landing centres to the town, non-availability of oxygen packaging at remote collection centres, difficulties in transportation of the collected fishes to the agent/stockist. Transportation of live fish and shellfish from areas of collection to destination or from areas of farming to the destination is an important activity of ornamental fish industry.

Proper collection, packing and transportation may help in increasing trade to a greater extent. Ornamental fishes destined for marketing, both domestic and export, have to use modern post-harvest technology or modifications of the current post-harvest technology to improve the post-harvest and post-shipment survival that is critical to the industry. It is in this context that the significance of packing and transport come into the picture. To overcome the problem of high mortality of fish species at different stages during transportation, it becomes essential to evaluate the most suitable and ideal condition for transportation. At present, the mortality rate during fish catching, collection, transportation is very high. The claim by the importers due to DOA (Death on Arrival) from India is on the higher side compared to the consignments from other developing countries. This is due to the lack of appropriate technology for fish packing & transportation/ shipment. Similarly, since the airfreight charges are very high, the exporters have no idea of the optimum number of a particular live fish to be packed in a container to reduce transportation cost. Such information is lacking for Indian fishes. The success of ornamental fish transportation depends on the following steps:

The purpose of managing a fishery is to maintain the resource so that it is renewable and therefore sustainable. Responsible aquaculture practices rely on sustainable production systems, to minimize impacts on the natural environment, and support resource conservation. In other words, the harvest of fish from the wild or their domestic culture, if performed with sound foundations of ecological and economic principles, can be sustainable and self-reliant commercial industry. In traditional subsistence fisheries, fishermen use primitive and inefficient gear to capture most ornamental fish. However, the supply of aquarium fish is not inexhaustible, and signs of over-fishing are becoming apparent in localized areas. With high demand and pricing of many beautiful species, ornamental fish are being harvested at greater volumes and higher rates, threatening the viability or sustainability of the fishery. Most endemic and sensitive species are restricted to very narrow specific habitats. Their survival, affected by physical over-exploitation for the aquarium trade, may be further hit by habitat alteration. No comprehensive studies have been carried out on the requirements of these endemic or sensitive exported species. In the absence of suitable impact studies, it is not possible to predict the impact of habitat alteration on these species. Exporters target more colorful varieties and since their ecological significance has not been studied, what long-term effect such selective exploitation will have on genetic diversity cannot yet be defined.

Apart from legislation that can be effectively implemented, eco-physiological and population studies of a quantitative nature are urgently needed to advise on the collection, maintenance and transport conditions that need to be followed by exporters to safeguard collected stocks from unnecessary mortality. Exporters are eager to learn and would be receptive to receiving appropriate, scientifically formulated, well-meaning practical advice. Studies should be targeted towards this end since it seems unlikely that the export trade can at present be voluntarily modulated on the basis of conservation requirements. Such a strategy could only become feasible after an adequately robust ecological database has been compiled, which would necessarily require time.

An effective management strategy needs to address not only aquarium-trade related matters but also policy and other matters in an integrated approach if we are to be hopeful of sustaining the ornamental fish industry in the long-term.

Ornamental fish culture has made giant strides in many countries in recent years. The industry is growing in leaps and bounds with involvement of even increasing number of aquarium hobbyists. A lucrative export market and high domestic demand have made ornamental fish industry a potential source for income generation. The range of species of ornamental fish available to the hobbyists is very large, with estimates of up to 1,500 species. As popularity of ornamental fish keeping has gained momentum, the need to transfer ornamental fishes from the resource abundant places to resource deficient places resulted in the marketing of ornamental fishes. In order to assess the marketing opportunities for ornamental fish, it can be classified as:

1. Choose the most appropriate option with a tick mark

i) Floating plants are required for breeding

a) Guppies

b) Angel fish

c) Swordtail

d) Gourami

ii) Breeding traps are generally used for

a) Egg-scatters

b) Egg-depositors

c) Livebearers

d) Nest-builders

“SOIL” the term is derived from Latin word “solum” which means, “floor”. Soil has been a defining component of humanity since the beginning of civilization. It holds the clues of past cultures, it supports the web of life connecting all ecosystems, provides materials to build houses, and provides the base for our food, feed, fiber and even some biofuels.

Soils are complex mixtures of minerals, water, air, organic matter, and countless organisms that are the decaying remains of once-living things. It forms at the surface of land and is the “skin of the earth.” Soil is capable of supporting plant life and is vital to life on earth. There are several general roles that soils play:

During the 19^th century various hypotheses were advanced about the origin of earth. These hypotheses can be grouped into two general classes:

1. Monistic hypotheses: The pioneers of this hypotheses believed that only one mass or body was responsible for the creation of the solar system. The representative of this theory is Nebular hypothesis. The advocates of this hypothesis were Kant and Laplace.

2. Dualistic hypotheses: The advocates of this hypothesis believed that two separate masses or bodies were responsible for the creation of the solar system. The representatives of this hypothesis are Planetesimal hypothesis and Tidal hypothesis. The pioneer of Planetesimal hypothesis was the great English scientist T. C. Chamberlain. The Tidal hypothesis was advocated by another English geographer named James Jeans.

Rock

A rock may be defined as “an aggregate of one or more minerals”. An aggregate of single mineral calcite gives rise to crystalline limestone. Granite is a combination of several minerals. Most rocks are hard and compact as granite and basalt, but some are loose and feebly aggregated as sandstone. Rocks possess certain characteristics such as structure, colour, specific gravity, cleavage and mineralogical make-up by which we can identify the rocks and also distinguish one from the other.

Mineral

A mineral is defined as “a natural substance, usually inorganic, having a definite chemical composition and commonly a definite molecular arrangement which is usually expressed in geometric form”.

Rocks and minerals formed under a very high temperature and pressure, when exposed to atmospheric conditions of low pressure and low temperature, they become unstable and weather. Soils are formed from rocks through the intermediate stage of formation of regolith (parent material) which is the resultant of weathering.

Soil formation takes place in two consecutive stages:

1. The weathering of rocks into regolith

2. The formation of true soil from regolith

The evolution of true soil from regolith takes place by the combined action of soil forming factors and processes. The first step is accomplished by weathering (disintegration and decomposition) and the second is associated with the action of soil forming factors which are known as pedogenic factors.

The pedogenic processes are dynamic and extremely complex involving several chemical and biological reactions, usually operating simultaneously in a given area. One process may counteract another, or two different processes may work in tandem to achieve the same result. Different processes or combination of processes operate under varying natural environments. The combined interaction of various soil forming factors under different environmental conditions set a furtherance to certain recognized soil forming processes. Pedogenic processes include:

There are over 100,000 different types of soil in the world, each with its own set of characteristics. If any soil is dug deep, one can see that it is made of layers, or horizons. The horizons together form a soil profile. Each profile tells a story about the life of a soil.

The development of soil profile is a constructive process where in disintegrated materials resulting from weathering of rocks and minerals get converted into a soil body. Soil Individual or Polypedon is a natural unit of soil that differs from its adjoining unit on the landscape in one or more properties. In modern soil taxonomy, polypedon is the unit of soil mapping. Apedon is the smallest volume recognizable in nature that can be called “a soil”.

Soil classification, or soil taxonomy as it is called, is grouping of soils in an orderly and logical manner based on soil properties (differentiating characters) for the purpose of studying and identifying them. The following are the purpose of soil classification:

To organize our knowledge of soils

To bring out and understand the relationships among the soils

To remember the properties of soils

To learn new relationships and principles in different soil groups

Physical properties of a soil greatly influence plant growth. The plant support, root penetration, drainage, aeration, retention of moisture and availability of plant nutrients are all linked with the physical condition ofthe soil. The physical properties of a soil which depend on the amount, size, shape, arrangement and mineral composition of its particles, also influence its chemical and biological behaviour.

Soil Structure Defined

Soil structure is defined as the arrangement of individual soil particles with respect to each other into a pattern. Structure describes the gross, over-all arrangement ofthe soil solids. In other words, soil structure is the ‘architecture’ of a soil.

Soils are composed of structural units, called “peds”. The peds consist of many individual particles, bound together by cementing agents like organic matter, clay and hydrous oxides of iron and aluminium. However, the strength of the bonds, the size and shape of the peds and the proportion of the soil particles involved in the peds differ considerably among soils.

Soil Consistence Defined

Soil consistence is the strength with which soil materials are held together or the resistance of soils to deformation and rupture. Soil consistence is measured for wet, moist and dry soil samples. For wet soils, it is expressed in terms of both stickiness and plasticity. Stickiness is the ability of soil materials to adhere to other objects. Plasticity is the ability of the soil materials to change shape continuously under a constant pressure and to retain the impressed shape when the pressure is removed. Soil consistence may be estimated in the field using simple tests or may be measured more accurately in the laboratory.

Soil Density

The density of a soil, as any other matter, is its mass per unit volume. However, in case of soil, because of its unique nature, the density can be expressed by two terms, viz., bulk density and particle density. Soil density is typically expressed in mega gram per cubic metre (Mg m^-3) which is numerically equal to g cm^-3.

Soil colour is the most obvious characteristic of soil. It has no direct effect on plant growth; however, it has indirect effect through temperature, moisture. Soil colour can indicate the climatic conditions under which it has developed and can be related to its parent material. It can also reflect upon its age, and the temperature and moisture characteristics of the climate. Thus, cooler regions tend to have grayish to black topsoils, due to the accumulation of humus. In moist warm regions, soils tend to be more yellowish-brown to red. Arid soils tend to be light in color (due to low organic content) and primarily express the color of their mineral content. Practically all colours occur in soils - white, red, brown, gray, yellow, black, etc. Predominantly soil colours are not pure, but mixtures. Frequently two or three colours occur, called as “mottling”.

15.1. Soil Temperature

Soil temperature affects plant growth directly; influences soil moisture, aeration, structure, microbial activity, decomposition of plant residues and availability of plant nutrients. Intermediate temperatures, near optimum for each crop, are the desirable temperatures for crop growth. Extreme temperatures are undesirable, lest crop growth would be retarded and weeds and germs may be favoured. Moderate daily variations are desirable as they lead to soil moisture distribution and aeration.

15.1.1. Factors Affecting Soil Temperature

The mean annual soil temperature is about 1°C higher than the mean annual air temperature. Soil temperature is influenced mainly by climatic conditions. The factors which affect the transfer of heat through atmosphere from the Sun also affect the soil temperature. The following are the factors that affect soil temperature:

Water is the elixir of life. It is required for the evapo-transpiration of growing plants. Water acts as a solvent and, together with dissolved nutrients, makes up soil solution from which plant roots derive nutrients. Soil water content controls soil air and soil temperature.

16.1. Forces of Water Retention

The forces responsible for water retention in soils are adhesion and cohesion. Adhesion refers to the attraction of solid surfaces for water. Cohesion refers to the attraction of water molecules for each other.

The force with which the soil particles retain water is defined in terms of pF scale (Schofield, 1935). pF is defined as “the logarithm to the base 10 of the numerical value of the negative pressure of soil moisture expressed in centimetres of water.”

The phenomena related to the retention and movement of water in soils, its uptake and translocation in plants and its loss to the atmosphere are all energy related. The more strongly water is held in the soil, the greater is its energy. It means that if water is to be removed from a moist soil, work has to be done against the adsorptive forces. The water movement is always from a zone where the free energy of water is high (standing water table) to one where the free energy is low (a dry soil). This is called soil water energy concept.

17.1. Soil Water Potential

The free energy of soil solids for water is influenced by:

i) Matric force: the attraction of the soil solids for water (adsorption) which markedly reduces the free energy (movement) of the adsorbed water molecules.

Water can move in the liquid and gaseous phases:

1. Liquid water

i) Saturated flow: Most pores are filled with water; water in this condition is tension free

ii) Unsaturated flow: Pores are partially filled with air; the water is under tension.

2. Water vapour

i) Diffusion: Water vapour moves by diffusion as a result of vapour pressure differences (partial pressure)

ii) Mass flow: Water vapour flows in a mass with other gases of the system in response to differences in total pressure.

Soil Colloids

A colloidal system is a two-phase heterogenous system in which one material in a very finely divided state is dispersed through the second phase. Solid in liquid (dispersion of clay in water) and liquid in gas (fog or clouds in atmosphere) are examples. The clay fraction of the soil contains particles less than 0.002 mm in size. Particles less than 0.001 mm size possess colloidal properties and are known as soil colloids.

Structure of Crystalline Clays

Soil clay minerals are of two types: crystalline and amorphous. Crystalline clays are made up of sheets of octahedra and tetrahedra of O and OH. Clays with alternating sheets of aluminium octahedra and silicon tetrahedra, are called, “1:1 clays” or “diphormic clays”. A sheet of octahedra is sandwiched between two sheets of tetrahedra in 2:1 clays which are called as, “triphormic clays”.

The building blocks of clay crystals are called “unit cells”. The geometry of octahedra has 3 voids in each half unit cell, equivalent to 6 negative valences. In order to nullify these 6 negative valences, 6 positive valences are needed. The 6 negative valences can be nullified by 3 divalent cations, one each in the three voids, or by 2 trivalent cations, leaving the third void empty. When trivalent cations such as Fe³+ and Al³+ fill two of the three voids, the clays are called, “dioctahedral clays”. When three divalent cations such as Fe , Mg and Mn fill up all the three voids, such clays are called, “trioctahedral clays”.

Ion Exchange Defined

By ion exchange is meant “the reversible process by which cations and anions are exchanged between solid and liquid phases, and between solid phases, if in close contact with each other”. For exchange of cations the term “base exchange” is exclusively used.

Soil Reaction

Soil reaction is an indication of the acidity or basicity of the soil and is measured in pH units. The pH scale ranges from 0 to 14, with 7.0 as neutral point. From pH 7 to 0, soil is increasingly acidic. From pH 7 to 14, soil is increasingly alkaline.

Pure H₂O ionizes to a very small degree, though to a measurable extent, so that it has the following equilibrium: both H+ and OH^- are in concentrations of 10^-7 moles L^-1.

Electrical conductivity (EC) is the ability of a material to transmit electrical current. In the soil, the EC is the ability of the soil solution to carry an electrical current and is a measure of the total amount of soluble salts present in the soil. Pure water is a poor conductor of electricity and increases in soluble salts water result in proportional increases in the conductivity.

23.1. Sources of Soluble Salts in Soil

The soluble salts in soils consist mostly of the cations sodium, calcium, and magnesium and the anions chloride and sulfate. Constituents that ordinarily occur only in minor amounts are the cation potassium and the anions bicarbonate, carbonate, and nitrate. The original and, to some extent, the direct source of all the salt constituents are the primary minerals found in soils and in the exposed rocks of the earth’s crust.

While the mean chlorine and sulfur content of the earth’s crust is 0.05 and 0.06 percent, respectively, sodium, calcium, and magnesium each occur in the range of 2 or 3 percent. During the process of chemical weathering, which involves hydrolysis, hydration, solution, oxidation, and carbonation, these constituents are gradually released and made soluble. When carbon-di-oxide, of atmospheric or biological origin, dissolves in water, bicarbonate ions are formed. Water containing carbon-di-oxide is an active chemical weathering agent that releases appreciable quantities of the cation constituents as the bicarbonates. The concentrations of carbonate and bicarbonate ions are a function of the pH of the solution. Appreciable amounts of carbonate ions can be present only at pH values of 9.5 or higher.

Soil organic matter (SOM) is one of the most complex materials existing in nature. Besides the organic constituents in undecayed plant and animal tissues, SOM contains both living and dead microbial cells, microbially synthesized compounds and an unending array of derivatives of these materials produced as the result of microbial activity. Soil organic matter contains most of the naturally occurring organic compounds. Some components of SOM are undoubtedly unique to the soil environment, particularly those involving inorganic-organic complexes.

The Carbon Cycle

The element that serves as a corner stone for cell structure is carbon. Plant tissues and microbial cells contain approximately 40 to 50% of C on dry weight basis. Yet, the ultimate source is the CO₂ of the atmosphere. The CO₂ is converted into organic C by the action of photoautotrophic organisms (higher plants and green algae). It has been estimated that the vegetation on earth’s surface consume some 1.3 x 10¹⁴ kg of CO₂ per annum which is about V₂₀ of the total CO₂ supply of the atmosphere or ¹/₁₀₀₀ of that in the ocean. Soil carbon constitutes the largest terrestrial pool of carbon.

The synthesis of humic substances is the least understood and the most intriguing aspect of humus chemistry. Studies on this subject are of enduring and continued research. Several pathways have been identified for the formation of humic substances during the decay of plant and animal remains in soil, the main ones being shown in Fig. 26.1.

To millions of different organisms around the world, soil is the habitat. A handful of soil can contain billions of soil micro-organisms. One gram of a fertile soil can harbour up to one billion bacteria. Only 5% of what is produced by green plants is consumed by animals, but 95% is consumed by microorganisms. Soil organisms are generally grouped into microfauna/microorganisms and macrofauna. The main soil microorganisms are bacteria, fungi, and protozoa. The macro-fauna includes oligochaeta, arthropods, mollusks and nematodes. These organisms play an essential role in soil formation and soil environment.

27.1. Bacteria

Bacteria are the major single-celled microorganisms in the soil ecosystem that are responsible for many important processes. There are many different types of bacteria and most of them are aerobic, requiring oxygen from the soil atmosphere. However, there are bacteria that live without oxygen and other types can live both with and without oxygen. The growth of these bacteria is limited by the food that is available in the soil. They decompose plant materials as well as other organisms’ wastes that contain plant nutrients in an unusable form and convert them into a form that can be used by plants. One such essential nutrient that is converted by bacteria is nitrogen. Nitrogen-fixing bacteria are able to use the nitrogen (N₂) that exists in the atmosphere and convert it through cellular processes into ammonia (NH₃). Nitrifying bacteria mix ammonia with water to create ammonium ion (NH₄+) and nitrate (NO₃^-), which can be used by other organisms.

Although plants can be grown to maturity in aerated nutrient solutions and other media, virtually all land plants, including those on which we depend for food, fibre and fuel, grow in soil. The soil has three-fold function to perform with respect to crop growth: physical, chemical and biological.

Soil pollution indicates the presence in the soil of any chemical or substance out of place and/or present at an abnormally higher concentration so as to adversely affect any non-targeted organism. Soil pollution often cannot be visually perceived or directly assessed, thus rendering it a latent danger. The Status of the World’s Soil Resources Report identified soil pollution as one of the main soil threats affecting global soils and the ecosystems services provided by them. Concerns about soil pollution are growing in every region. Recently, the United Nations Environmental Assembly (UNEA-3) adopted a resolution calling for accelerated actions and collaboration to address and manage soil pollution. This consensus, achieved by more than 170 countries, is a clear sign of the global relevance of soil pollution and of the willingness of these countries to develop concrete solutions to address the causes and impacts of this major threat.

29.1. Sources of Soil Pollution

The main anthropogenic sources of soil pollution are the chemicals used in or produced as byproducts of industrial activities, domestic, livestock and municipal wastes (including wastewater), agrochemicals, and petroleum- derived products. These chemicals are released to the environment accidentally, for example from oil spills or leaching from landfills, or intentionally, as is the case with the use of fertilizers and pesticides, irrigation with untreated wastewater, or land application of sewage sludge. Soil pollution also results from atmospheric deposition from smelting, transportation, pesticide applications and combustion of many substances as well as radionuclide fallouts from atmospheric weapons testing and nuclear accidents. New concerns are being raised about emerging pollutants such as pharmaceuticals, endocrine disruptors, hormones and toxins, among others, and biological pollutants, such as micropollutants in soils, which include bacteria and viruses.

Soils play a vital role in the health of ecosystems in the world. Soils connect with air, water, rocks and organisms and are responsible for a multitude of functions in the global ecosystem services. These functions include providing habitat for most living things, air composition and quality, temperature regulation, carbon and nutrient cycling, water cycling and quality, and natural waste recycling. Mankind cannot survive without these soil functions.

30.1. Habitat

Soils are the environment in which plants grow. They provide heat, nutrients and water to nurture plants to maturity. These plants, together with other plants and organisms, create ecosystems. These plants then provide valuable habitat and food sources for animals, bacteria and other things. Ecosystems depend on the soil and soils determine the nature and kind of ecosystems.

Soil quality is the capacity of the soil to function, within its natural or managed ecosystems, to sustain plant and animal productivity, maintain or enhance water and air quality, support human and animal health and habitation. This is not limited to agriculture, though most work and evaluation has occurred on agricultural lands.

Soil health refers to the condition of the soil and its potential to sustain biological functions, maintain environmental quality and promote plant and animal health. Healthy soils are the key to food security and sustainable future. They support sustainable food production, mitigate and adapt to climate changes, filter water, enhance resilience to floods and droughts and so much more.

India is endowed with varied types of soils and this could be attributed varied relief features, landforms, climatic realms and vegetation types in the subcontinent. In ancient times, soils used to be classified in India into fertile and sterile soils. Later, the inherent characteristics and external features of soils such as texture and colour, were used to classify the soils. Based on texture, soil types were identified as sandy, clayey, loam, etc. In terms of colour, they were red, yellow, black, etc.

Scientific surveys of soils in India have been conducted by various agencies since independence. All India Soil Survey Organization, established in 1956, carried out detailed soil surveys in the catchment areas of major river valley projects like the Damodar Valley. Later, the National Bureau of Soil Survey and the Land Use Planning (NBSSLUP) ofthe Indian Council of Agricultural Research, established in 1976, made extensive studies on Indian soils and classified them as per the USDA SoilTaxonomy

Horticulture deals with the art, science, business and technology of cultivation and management of horticultural plants. The word Horticulture is derived from two Latin words viz. ‘Hortus’ (means garden) and ‘Culture’ (means growing). Horticulture is an aesthetic science that deals with cultivation of fruit, vegetable, spice, plantation, medicinal, aromatic and flower crops. There is a vast therapeutic use of horticulture wherein gardening and aroma therapy are used to deal with new age maladies like depression and various addictions.

In ancient times, huge gardening spaces to grow large number of fruits, vegetables and flowers were available and these areas were demarcated with the help of high walls. This enclosed area was referred to as garden. This led to the term garden culture. The land area is decreasing due to industrialization and population growth, at the same time, there is a drastic increase in demand for horticultural produce. To meet the increased demand for horticultural produce and to cope up with the space constraints, multitier cropping systems, vertical gardening and other intensive cultivation practices are being resorted to. Hence, horticulture may also be described as the “Practice of growing and manipulating plants in a relatively intensive manner”.

Presently, fruits, vegetables, flowers and ornamentals are grown not only within the home premises, but also in large quantities on a commercial scale. In other words, many horticultural crops throughout the world are grown primarily as business enterprises. Thus, horticulture has two aspects in general i.e., the amateur and the professional. In addition, with the establishment of horticultural experiment stations as an integral part of colleges and universities, comparatively a large amount of scientific information on the behaviour and cultivation of horticultural plants and products is freely available. This information or literature, constitutes the science of horticulture, and the application of this scientific information constitutes the “Technology of Horticulture.” Thus, present day horticulture may be defined as the science and technology of production, processing and merchandising of fruits, vegetables, flowers and ornamentals where each crop has its own science and technology. Consequently, horticulture may appear differently to different people. To a teacher, professor, research scientist, extension official and landscape architect, it is an applied science and a profession, while to a commercial producer, wholesaler, a retailer of horticultural products, or to the manufacturers or seller of horticultural products, it is a business. It is also a fascinating hobby for connoisscur.

Horticulture is a wide field and includes a great variety and diversity of crops. In general, these crops are classified as follows:

1. Crops grown for the food and/or vitamin and mineral content, for e.g., apple and sweet potato.

2. Crops grown for their beverage properties, for e.g., tea and coffee.

3. Crops grown to beautify the environment, for e.g., the grasses of the well planned lawn.

4. Crops grown to express sentiments, for e.g., cut roses, jasmine.

5. Crops grown for perfume for e.g., rose, jasmine.

6. Crops grown for spices for e.g., pepper, nutmeg.

The Horticultural crops show wider adaptation and therefore exact delineation of the agro-climatic areas specific to each crops is not possible, except for the typical temperate and tropical species. However, our country can be broadly divided into seven zones for horticultural crops as indicated below:

1. Temperate Northern Region

Comprising of states of Jammu & Kashmir, Himachal Pradesh, Hilly areas of Uttar Pradesh and West Bengal. Temperate fruits, cool season vegetables are the important horticultural crops in the zone.

2. North Western Arid Region

Comprising ofthe entire Rajasthan state, Gujarat and parts ofPunjab & Haryana. Arid fruit crops like ber, pomegranate, amla, date palm, wood apple and seed spices like coriander, cumin, fennel occupy major area in this zone.

3. North Eastern Sub-tropical Humid Region

Comprising of states and union territories like Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland and Tripura. Fruit crops like banana, pineapple, citrus, jack besides plantation crops like tea and large cardamom are also grown here.

The Government of India has established boards for important crops. The boards are statutory bodies which help in guiding the production and export. The main objectives for setting up the boards are -

To monitor and promote the export of primary items.

To empower the producers by providing trainings and close guidance.

To conduct research to improve the commodity, e.g. Central Coffee Research Institute, Coir Research Institute etc.

To advise the government on policy matters such as price fixing, fixing quota for export and signing trade agreements.

To promote the commodity by opening offices and outlets in India and abroad.

To showcase the commodity by participating in trade fairs and exhibitions.

A number of tools, implements and machineries are used in cultivation of horticultural crops to make every operation easy and efficient. There are a number of operations involved in cultivation of horticultural crops, like making of nursery, propagation of plant material, field ploughing, breaking of clods, levelling, making bunds, sowing and planting, plant protection, training, pruning, harvesting, lawn mowing etc. All these operations are physically taxing and cannot be carried out efficiently without proper tools, implements and machineries. Following are some important tools -

1. Bill hook: To cut and remove big sized unwanted branches of trees.

2. Buckets and plastic pots: used in the orchard for spraying, transport water, carry harvested produce etc.

3. Budding and grafting knife: The budding and grafting operations in propagation of many horticultural plants are carried out using budding and grafting knife.

4. Country plough: Used in field preparation for ploughing the soil, incorporation of organic manures into the soil at the time of last ploughing, summer ploughing in conserving of soil moisture.

5. Crow bar: Used to loosen the soil, digging and deepening the pits and channels.

6. Dibbler: Used to make holes and sow the seeds in the nursery as well as in the main field.

7. Digging fork: It is of a great use in harvesting the tuber crops without damaging the produce.

The performance of plants is affected by the soil in which it grows and climate and micro climate of its surroundings.

Impact of soil

The soil provides anchorage, nutrients and water for plant growth. Soil fertility status, structure and texture influence the plant growth and productivity.

Classification of soil

On the basis of the organic and inorganic contents and particle size and texture, the soils have been classified. The inorganic matter in the soil constitutes of varying amount of sand, silt and clay, on the basis of which the soils are classified as follows.

Sandy soil

These soils have coarse textured and large pore spaces, have poor water holding capacity. Retention of nutrients in this soil is very poor. This type of soil is suitable for precocious crops. Sandy soils initiate rapid root growth, hence good as propagating medium. Since sandy soils has low in nutrient content, supplementation of adequate nutrition is imperative to achieve good plant growth.

Nutrient management is one of the key aspects that ensure good quality produce in optimum quantity. Nutrient availability influences growth and productivity of crops. Sixteen elements are recognized as essential nutrients for growth and development of plants. These essential elements are carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium, sulphur, iron, zinc, manganese, copper, boron, molybdenum and chlorine. While carbon, hydrogen and oxygen are derived from air, soil and water, other elements are taken by the plant roots from the soil, according to the requirement of the plant. The soil contains these elements in varying quantities depending on the origin of the soil. According to the quantity of requirement of these elements by plants for its various growth processes,the elements are classified into different categories.

Major nutrients or primary nutrients - These are required by plants in large quantities because they are involved in all the processes of plant growth and development. Major nutrients are nitrogen, phosphorus and potassium.

Secondary nutrients - These are required by plants in relatively smaller quantities for growth and development. Secondary nutrients are magnesium and sulphur.

Micro nutrients - As the name suggests, these are required by plants in minor quantities for their physiological processes. These elements are iron, zinc, manganese, copper, boron, molybdenum and chlorine.

Each of the plant nutrients has a definite quantitive role and specific function in the physiological processes of plants. If any of the essential element is deficient or absent in the soil sysem, the plant growth is affected negatively and this is reflected as inferior quality produce. On the contrary, if a nutrient is excess in the soil system, it hinders in absorption of other nutrients and also may itself be toxic. Hence to get the required growth, quality and quantity of the produce, optimum availability of all the nutrients should be ensured.

Water is an extremely essential component in plant growth and development. It is of utmost importance for photosynthesis, cell division, cell growth / elongation, respiration, nutrient uptake, mineral utilization and much other metabolic process, which directly affect the quantity and quality of the produce. Hence quantity and quality of water play a vital role in performance of a crop. A well distributed water supply, throughout the growth of plant is essential. Rainfall is the major source of water for the crops. Rainfall recharges the surface water resources such as rivers, streams and ponds and also the ground water resources like wells.

Different crops are grown in a field. Any plant growing in a place where it is not desired competing with the main crops, has to be weeded out and such plants are called ‘weed’.

Effect of weed menace The weeds

Reduce crop yield and production efficiency. It competes with the main economical crop for space, water and nutrients.

Reduce crop quality.

Hamper intercultural operations.

Reduce crop quality.

Obstruct the flow of water in the irrigation channels.

Exert allelopathic effect on crops.

Harbour insect and pests, which affect the main crop of interest.

Increase the cost of production.

Plant propagation techniques refer to the methods by which the plants are multiplied and increased in number.

Methods of Propagation

i) Sexual Method of Propagation - Seeds are used as propagating material.

ii) Asexual Methods of Propagation - Plant parts, other than seeds are used for plant propagation.