eChapters

INTRODUCTION

Fish live in a variety of watery habitats and comprise around 50% of all vertebrate species worldwide. There are approximately 21,723 known living fish species out of a total of 39,900 vertebrate species, with 8,411 found in freshwater habitats and 11,650 in marine environments (Jayaram, 1999). Fish are used as markers of contamination and contribute significantly to the preservation of human history and welfare, either directly or indirectly. According to Mittermeier et al. (1997), India ranks eighth in the world for freshwater biodiversity, making it one of the nations with significant biodiversity. There are over 2,500 fish species in India; roughly 930 of them are found in freshwater environments, and roughly 1570 are found in marine ones (Kar et al., 2006).

Fish diversity is particularly rich in the northeastern part of the nation; studies have shown that there are 267 freshwater fish species from 114 genera distributed over 38 families and 10 orders (Mahanta et al., 2003). Fish plays a crucial role in Assam's cuisine, where a wide range of fish species may be found in the region's floodplain wetlands because of the subtropical climate, favorable ecological and topographical circumstances, and inherent capacity for stocking. Assam's waters, including its wetlands, are home to around 217 fish species, representing 104 genera, 37 families, and 10 orders, according to Goswami & Singha (2023). Assam's lakes and marshes are vital for supplying the state's domestic fish needs, fostering economic growth, and giving the general public access to fairly priced food. In Maguri Beel, several fish are in danger of going extinct because of pollution, habitat damage, and the introduction of non-native species, overexploitation and human activity (Moyle & Moyle, 1995; Malakar & Boruah, 2017). The 2020 oil spill incident might have had a major impact on the variety of the ichthyofauna's composition. To address the same, a comparison of the same with earlier research is desperately needed. As a result, the current study intends to examine the fish variety of Maguri Motapung Beel, close to Motapung Village in the Tinsukia region of Assam and Dibru-Saikhowa National Park.

INTRODUCTION

An expanding aquaculture industry that offers high incomes and job opportunities to people worldwide is ornamental fish farming. With over 2 billion live ornamental fish traded globally, the ornamental fish trade has become a very lucrative sector (Das & Biswas, 2016; Katia, 2001) with global net worth of more than 20 billion USD. According to Saxena (1994), the most significant factor influencing an ornamental fish's market value is its vibrant body colouration. Fish are incapable to synthesize carotenoids De novo (Goodwin 1951),and rely on dietary carotenoids for its body pigmentation (Hata and Hata, 1973). So, there is hence a direct correlation between pigmentation and dietary carotenoids(Halten et al., 1995). Aquatic animals' skin, meat, shell, and exoskeleton are coloured red, orange, and yellow due to a class of naturally occurring lipid-soluble organic pigments called carotenoids (Pailanet al., 2012). Fish skin and muscle colour regulation is significantly influenced by dietary carotenoids (Ahilan et al., 2008). The freshwater ornamental fish industry has encountered the issue of fadingfish body colouration, particularly in cases where the fish are reared in captivity for extended periods of time and subjected to rigorous cultivation conditions (Das and Biswas, 2016). According to Das and Biswas (2016), an ornamental fish's food should generally be nutritionally balanced, appetizing, resistant to crumbling, water stable, buoyant, and enhance or retain the fish coloration.

The phenomena of coloration in fish are quite significant and have a direct impact on its aesthetic value. If pigment-enriched feed can be prepared and used to increase coloration, the fish will undoubtedly have better quality and a cheaper price tag. Detailed research on colour enrichment in native ornamental fish using formulated feed is lacking (Das and Biswas, 2016). For the purpose of colour enrichment in fish, native plant sources have been used. Choubert (1979), Boonyaratpalin and Phromkunthong (1986), and Alagappan et al. (2004), utilized spirulina as a source of carotenoid colours for fancy carp and rainbow trout. Enhancement of pigmentation of Cyprinus carpio and Carassius auratus with microalgal biomass supplementation has demonstrated that Chlorella vulgaris is just as effective as synthetic colours (Gouveia et al., 2003). Alagappan et al. (2004) observed increased body pigmentation in Trichogaster trichopterus using Spirulina sp. algae as a source of carotenoid pigment. The body pigmentation of goldfish (Carassius auratus L.), red swordtail (Xiphophorus helleri), and tiger barb (Puntius tetrazona) was enhanced by feeding with marigold petal diet (Boonyarapatin and Lovell, 1977; Ezhil et al., 2008; Alma et al., 2013). Using natural sources of carotenoid pigments to improve the colour of ornamental fish is a cost-effective and ecofriendly solution. Due to the aforementioned information, the current study was carried out to assess how dietary natural carotenoids from source such broccoli (Brassica oleracea var. italica) effects the development and coloration of Blue Gourami, Trichogaster trichopterus, one of the important ornamental fishes with high market value.

INTRODUCTION

Aquaculture is a technology driven industry which relies a lot on research to develop species diversification in culture system as well as in the appropriate technology for commercial production. The rapid development of aquaculture in the world depends largely on the availability of fish feed; which are traditionally based on fish meal as the main protein source (Hardy & Tacon, 2002; Krishnankutty, 2005; Yigit et al., 2006) but the major challenge is its availability, quality and cost (Ghazala et al., 2011; Tabinda and Butt, 2012). In the aqua feed formulation, protein is the main but expensive ingredient and its quality and quantity in fish feeds formulation plays a vital role in promoting fish growth (Pandian, 2001). Dietary protein provides essential and non essential amino acids to synthesize body protein and energy for maintenance. According to fish species, fish size, dietary protein sources and environmental conditions protein requirements ranges from 300 to 550 g /kg (NRC 1993).

In India there is a significant development in fresh water aquaculture in last few decades contributing greatly to overall fish production of the country. The fresh water aquaculture is crossing the traditional boundary of concentration on farming of major carp and entered the arena of diversification to the culture of other species like catfishes. So far in India majority of research works were concentrated on development of commercial fish feed mainly for carps and shrimps. To fulfill the objectives of large scale culture of cat fishes and development as an economic proposition, it is necessary to take up induced breeding and larval rearing of commercially important catfishes in controlled conditions and develop easily adoptable package of practices of the same to cater to the needs of interested fish entrepreneurs. Among the catfishes, Clarias magur, an air breathing species and popularly known as ‘magur’ or ‘walking catfish’ is a high valued fish in the Indian subcontinent and fetches higher price than many other fishes including major carps and it is highly revered for its nutritious flesh which is therapeutic in nature, hence, better prospects are there for developing its culture (Hussain et al., 2016). Vishwanath (2010) reported that this species is very much popular in Bangladesh due to use as important part of the diet for children and lactating mothers and also prescribed as diet for the convalescent of the patients. This fish is highly regarded for food due to its high protein (15.0%), low fat (1.0%) and high iron content (710mg/100g tissue). Paul et al. (2015) in their studies on Indian catfish namely magur (Clarias batrachus) and singhi (Heteropneustes fossilis) for proximate composition and mineral content concluded that both the fishes are rich in protein, fat and minerals content irrespective of their size and season.

INTRODUCTION

The aquaculture industry is regarded as one of the most advanced food production industries globally. From 2010 to 2020, it grew at an average annual rate of 4.6%, reaching 122.6 million tonnes of live weight (FAO, 2022). Sustainable aquaculture proposes numerous profits to attain economic progress through well usage of natural resources (FAO 2017). The expansions in the sustainable aquaculture business are challenging due to the inadequate number of available natural resources and industrialized effects that released to the surround environments (Costa-Pierce et al. 2012; Verdegem 2013). Particularly in intensive system, increased higher organic matter concentrations raise several future issues, including acute harmful, chronic impacts (Piedrahita 2003). Recently, Innovative biofloc technology system (BFT) is one of the most popular methods to combat these problems.

Biofloc is a climate-smart technology that relies on mass synthesis of in situ microorganisms (Ogello et al., 2021). The BFT permits high stocking densities and higher fish productivity (Ogello et al., 2021) while requiring limited or zero water exchange in to sustain the flocs (Emerenciano et al., 2017). The power of BFT aligns with the "cradle to cradle" concept that outlined by McDonough and Braungart (2002), which omits the phrase "waste”. In BFT, nitrogen wastes that generated from feces of aquatic animals and residual feeds are transformed into the microbial protein that becomes feed for the same creatures (Minaz and Kubilay 2021). Numerous microorganisms, including bacteria, microalgae, protozoa, and zooplankton, are present in biofloc particles (Ray et al. 2010a). Hence, biofloc can incorporate the diet of aquatic species, which utilises the natural productivity in the culture system as a feed source (Wasielesky et al. 2006; Emerenciano et al. 2012a). This microorganisms are recognised for their contributions to (i) preserving high water quality (Emerenciano et al., 2017), (ii) enhancing culture efficiency by lowering feed conversion ratio (FCR) and costs of feed (Hargreaves, 2006). (iii) biosecurity (Defoirdt et al., 2004), and (iv) conserving greenhouse gases (GHG) (Manan et al., 2016). These four biological roles of microorganisms in BFT units are factors of high fish production, profitability and environmental protection (Ogello et al., 2021).

INTRODUCTION

The Food and Agriculture Organization (FAO) of the United Nations defines aquaculture as the cultivation of aquatic organisms such as fish, mollusks, crustaceans, and aquatic plants by individuals or corporations. In aquaculture, interventions are made in the rearing process to enhance production. While aquaculture is a practice with origins dating back more than 3000 years, Aquaculture products have only recently been recognized by the United Nations Statistical Commission as distinct global commodities, despite the practice having origins dating back more than 3000 years. According to the FAO's "Global Aquaculture Production" database, the annual global production of aquaculture has increased at an average rate of around 8% over the past three decades (since 1980). Despite a recent slowing in global trends, growth remains higher than any other major animal food production sector. This rapid global increase in production is occurring alongside a slow decline in marine fisheries catches. There is a growing global focus, largely driven by demand from Western countries, on increasing the intensive production of omnivorous and carnivorous species farmed and harvested in maritime and brackish coastal environments, a practice known as mariculture. The farming of these species, such as salmon, groupers, seabasses, and prawns, typically relies heavily on inputs such as wild post-larvae and juveniles, fishmeal, fish oils, as well as significant amounts of water, land, and energy. As a result, mariculture has faced widespread criticism due to its often negative impacts on marine and coastal ecosystem health. Negative associations have been drawn between mariculture and its effects on marine capture fisheries and food security.

Study done in India on various aspects of marine copepods are those of Krishnaswamy (1952), Kartha (1959), Ummerkutty (1960, 1966), Ganapathi et al. (1961), Kasturirangan (1963), Saraswathy (1966), Abraham (1970), Silas and Pillai (1973), Sarladevi (1979), Sarkar et al. (1985), Madhupratap and Haridas (1986), Wells and Rao (1987), Gajbhiye et al. (1991), Madhupratap (1999), Kesarkar and Anil (2010), Ramanibai and Shanthi (2011), Srichandan et al. (2014). Jayabarathi et al. (2015), Nishida et al. (2015), Arunpandi et al. (2017), Loka et al. (2017), Deepika et al. (2019), Kaviyarasan et al. (2019), Khandagale et al. (2022), Nawaz et al. (2023), Thangaraj and Vijayanand (2023).

Copepods are planktonic crustaceans, which occur in marine, fresh as well as brackish waters. They represent about 80% of the zooplankton in the ocean. There are more than 210 families, 2400 genera and 24000 species identified in this group. Planktonic copepods are considered to be the most abundant metazoans on earth.

The name 'copepod' is derived from the Greek words meaning 'animals with oar shaped foot' i.e., ‘kope’ means oar and ‘podos’ means foot (Stottrup,2003). Copepods are important secondary producers and primary consumers and ultimately contribute significantly to the food chain in large ecosystems.

Copepods are very hardly planktonic forms which can withstand most of the unfavourable conditions and can produce diapause eggs and resting eggs to survive in these conditions. Most of the copepods can adjust wide range of salinity and temperature levels. Due to its hardy nature, copepods can be easily introduced into all types of water bodies.

Copepods forms important food for many aquatic animals especially fishes. Certain fishes and fish larvae were evolutionary adapted to feed on copepods. Copepods have been found to be nutritionally superior to almost all other live feeds.

Increasing pressures exerted on the environment by humans make protection of natural areas crucial for the preservation of biological diversity. Protected areas are one of the most effective tools available for conservation of biodiversity.

The IUCN defines a Protected Area as ‘an area of land and/or sea specially dedicated to the protection and maintenance of biological diversity, and of natural and associated cultured resources, and managed through legal or other effective means.

Since 1986, the IUCN commission on National Parks and Protected Areas (CNPPA) has been promoting the establishment and management of a global representative system of Marine Protected Areas (MPAs) which play a critical role in the conservation of biodiversity. MPAs are growing in importance globally as practical and potentially effective options for the management of fisheries, the protection of biodiversity and the generation of income from eco-tourism. The effective management of MPAs to ensure that they meet their declared objectives poses many challenges.

The IUCN has defined an Marine Protected Area (MPA) as ‘Any area of the intertidal or subtidal terrain, together with its overlying water and associated flora, fauna, historical and cultural features, which has been reserved by law or other effective means to protect part or all the enclosed environment (Kelleher,1999).

INTRODUCTION

Coral reefs are fragile and most diverse and valuable ecosystems on earth. The stony corals are formed from the tiny, soft colonial organisms called polyps. They provide enormous ecological, economic services, and cultural value to hundreds of millions of people. They are significantly contributing to the nutrition, economic security and protection from natural disasters. They are often termed as the rain forests of the sea.

Coral reefs were first appeared 485 million years ago during the early Ordovician period. They belong to the class Anthozoa of animal phylum Cnidaria, which includes sea anemones and jelly fish. Coral reef is an under water ecosystem which is characterized by reef-building corals. Unlike sea anemones, colonies of coral polyps secrete a hard exoskeletons called reef which is made up of calcium carbonate to support and protect the corals. These reefs grow best in warm, shallow, clear, sunny and agitated water.

BIODIVERSITY

The term biodiversity was coined by Walter G. Rosen in the year 1985. Biodiversity refers to the variation among living organisms that can be found in a particular area such as terrestrial, marine and desert ecosystems and the ecological complexes to which they are a part. The study of biodiversity helps to understand the ecological stability, economic and ethical importance. Coral reefs are believed to have the highest biodiversity on the planet even more than a tropical rainforest. Though the coral reefs distributed in less than one percent of the ocean floor, they provide habitat for more than 25% marine life with more than 4,000 world’s fishes. They act as protective nurseries to many fish species, and shelter small fishes to grow. Coral reefs diversity is so rich that we do not have a firm count on all the species that live within it and every year discover new species.” There are about six thousand coral species in the world, in which few are growing in warm shallow waters near coastlines while others in the dark, cold seafloor of the open ocean.

INTRODUCTION

Species of the Clupeiformes (Teleostei), commonly known as herrings, shads, menhadens, sardines, anchovies, and their relatives, are a major component of forage fishes in coastal ecosystems and dominate worldwide forage fish landings (Tacon and Metian, 2009a; FAO, 2020). Clupeiformes are globally distributed fishes with having nearly 419 marine, freshwater, and diadromous species (Bloom and Egan, 2018) and they are filter-feeding fishes that form large schools having a diverse group of trophic guilds and habitats (Bloom and Egan, 2018). Additional to providing ecological and economic support, clupeiforms contribute to global food security given their abundance, easy access, and exceptionally high nutrient content (FAO, 2018). In some human communities, clupeiforms comprise the major or the sole protein source (Alder et al., 2008; Mohanty et al., 2019). Historically, clupeiform presence has been associated with persistent human settlement, growth, and survival (Thornton et al., 2010; Levin et al., 2016).

Clupeiform fishes are ecologically diverse and span all aquatic habitats, including coastal and open marine environments, oceanic islands, estuaries, and freshwater rivers and lakes (Whitehead, 1985; Lavoue et al., 2013). Species can be restricted to marine, estuarine, or fresh waters, or they can be euryhaline, where a subset exhibit diadromy (Whitehead, 1985). Strictly marine clupeiforms (33.7% of all species) are distributed in every ocean, except for the Southern Ocean (Whitehead, 1985), while strictly freshwater species (17.8% of all species) are found on every continent except for Antarctica (Bloom and Egan, 2018). Major threats to clupeiforms are similar to those found for other groups of fishes (e.g., Roberts and Hawkins, 1999; Reynolds et al., 2005), with overexploitation as the leading threat for all clupeiforms in all habitats. While overexploitation may be the most prolific threat by impacting the highest number of clupeiforms, pollution may be the most detrimental, as it affects greater numbers of CR species. When compared to other economically and ecologically important fish groups globally assessed using the IUCN Red List methodology, clupeiforms have the lowest estimated percentage of threatened and NT species overall. Using the midpoint of species evaluated as elevated concern, roughly 11% are currently at high risk compared to approximately 22% of tunas and billfishes (Collette et al., 2011), 19% of sparids (Comeros Raynal et al., 2016), and 19% of groupers (Sadovy de Mitcheson et al., 2020).

INTRODUCTION

Biodiversity can be useful as an ecosystem indicator for conservation and monitoring, through continuous assessment of its main properties including stability, primary productivity, exploitation tolerance and even global environmental changes (Douglas et al., 2012). Crustaceans are found one of the most morphologically diverse taxonomic groups on the planet (Martin and Davis, 2001). Among them, decapods are the most studied taxon, mainly on account of the commercial interest of some species and their great diversity (Isarch and Munoz, 2015). Decapods are chiefly composed of marine species that live in waters depths ranging from shallow to deeper than 5000 m. Isarch and Munoz (2015) described the importance of this group lies in several factors such as the great biomass they represent, their significant role in marine food webs and the commercial interest of many decapod species. Order Decapoda comprises the commercially important shrimps, crabs and lobsters. Out of 649 species of marine crabs so far recorded from Indian waters, only 12 species of edible crabs namely Portunus sanguinolentus, P. plagicus, Charybdis feriatus, C. lucifera, C. annulata, C. natator, Scylla serrata, S. tranquebarica, Matuta lunaris, Sesarma tetragonum and Varuna litterata, which inhabit the coastal waters and adjoining brackishwater environments, support commercial fisheries (Menon and Pillai, 1996). However substantial quantities of crabs are landed every year as by-catches of shrimp trawlers and indigenous fishing units throughout the county.

India represents one of the major contributors to the world production of marine crustaceans. Shrimps constitute as the main seafood export industry for the major foreign exchange earner as well as a source of livelihood for millions of fish workers. As shrimps are targeted for fishing, information on the present status of the fishery is critical for implementation of proper management. Some of the important penaeid shrimps that support commercial fisheries along the Indian seas are Fenneropenaeus indicus, P.semisulcatus P.monodon, P.merguiensis, P.japonicus, P.penicillatus, Metapenaeus dobsoni, M.monoceros, M. affinis, M. kutchensis , M. brevicornis, Parapenaeopsis stylifera, P.hardwickii, P.sculptilis, P.maxillipedo, P.uncta, Trachypenaeus curvirostris, Metapenaeopsis stridulans, Parapenaeus longipes, Solenocera crassicornis and S.choprai (Mohan Joseph and Jayaprakash, 2003). Rajkumar et al. (2015) carried out molecular identification of shrimp species, Penaeus semisulcatus, Metapenaeus dobsoni, Metapenaeus brevicornis, Fenneropenaeus indicus, Parapenaeopsis stylifera and Solenocera crassicornis from Tamil Nadu, India.

INTRODUCTION

Ecosystem services and biodiversity conservation are well recognized as essential to human well-being and have become a policy priority. India is gifted with a large coastline and vast stretches of coastal wetlands. The estuaries and back waters which may include mangroves, mud flats, bays etc. extend over a large part of the Indian coasts. The mangrove ecosystem functions as a habitat for nurseries, thus benefiting fishers in the food chain (Mumby et al., 2004; Venkatachalam et al., 2018). Mangrove habitats increase the survival ratio of young fish that migrate to other offshore habitats when they mature, resulting in the enrichment of fish biomass in adjacent mangrove areas (Mumby et al., 2004; Aburto-Oropeza et al., 2008). Mangroves enhance fish production by providing food and shelter to fishery resources. Mangrove forests are highly productive, with average primary productivity level similar to that of tropical terrestrial forests (Alongi, 2009). Therefore, mangrove loss could have a devastating effect on fishery outcomes. The estimated fish catch is up to 70% higher in mangrove areas than in non-mangrove areas (Das, 2017).

NATURE OF MANGROVE FORESTS

Mangroves are amongst the most productive marine ecosystems on the Earth, providing a unique habitat opportunity for many species and key goods and significant services for human beings. They are salt tolerant plants, and are found distributed growing in estuaries, lagoons, backwaters and bays at the land-sea interface in tropical and subtropical areas of the world. Mangroves thrive on low-oxygen through the breathing roots or pneumatophores that are used for respiration. They need freshwater for their growth and so they live at the sea edge, they must remove the salts from the water that is taken in by the roots.

11.1 Quality

• Quality of fruit or any other commodity is combination of attributes, properties or characteristics like appearance, texture, flavor and nutritive value that determine their value to the consumer.

• Keeping quality is also an important quality attributes in all fruits.

• Quality parameters • Appearance (size, shape, color and freedom from defects)

• Texture (firmness and juiciness)

• Flavors (swetness, sourness, bitterness, astringency, aroma and off f lavour)

• Nutritional (vitamins and minerals)

• Quality management Quality management is a method of ensuring the effectiveness of all the factors those implemented to improve and maintain the quality in acceptance form at consumer’s level.

11.2 Pre-harvest management of quality

11.2.1 Genotype and rootstock management

10.1 What is nutrient management?

• Nutrient management is an important component in orchard management for high efficiency and high fruit quality. Fruit trees are perennial woody plants which can store nutrients and then release them for growth.

• Therefore, the nutrient uptake of fruit trees includes the total nutrients of the fruits, leaves, new branches, and time increments of storage. Nutrient uptake is different under different yield levels. For example, the N uptake of apple trees was 100–120, 110– 130,120–140, and 130 150kg/ha under yield levels of 30, 45, 60, and 75t/ha, respectively.

• Basal fertilization is considered to be important for high-quality fruit production by providing nutrients for tree growth and also improving soil structure which promotes better root development. It is usually recommended and immediately applied during the dormant season up to autumn, after fruit harvest.

• Top dressing applications are usually chemical fertilizers which are applied two to four times before bud break or prior to or after blooming and at the fruit enlargement stage, depending on the requirements of each type of fruit tree.

• Using this INM method, the total nutrient demand is calculated according to target fruit yield level and NPK fertilizers are recommended based on soil fertility index (High, Moderate, and Low soil fertility) and nutrient demand with different stages. For moderate apply trees, most of N fertilizer is applied in autumn after picking to add N storage and renew tree vigor, and most of the P fertilizer is applied in spring with flowing stage to improve flower bud quality, and most of the K fertilizer is applied in summer fruiting period to improve fruit quality. Management of high yielding fruits using suitable pruning, and irrigation, are combined in this INM

Introduction

• Successful horticultural production is not possible without sufficient moisture regimes and for that, the appropriate techniques should be adopted.

• In the total cultivated land of India, 75 % of land contributed as a rainfed area or dry land area in which 60% with semi-arid and 19.3 % of area with arid zone.

• The irrigation facilities are covered only 38 % of the total cultivated land of the country.

• The moisture is always the limiting factor in arid area.

• So, conservation of soil moisture or water management is the most important task for arid fruit production.

• Out of total cultivated area of Horticultural production, l lakh ha is under arid or semi-arid.

• In arid area, some fruit crops with specials features are adapted for their production. So, in this area, the soil moisture conservation or the water harvesting techniques is the prime important tools for crop production with best management systems.

8.1 What is stress?

• Physics:Mechanical force per unit area applied to an object.

• Biology:Stress is any adverse environmental factor or condition that affects normal metabolic or physiological processes. It may be :

• Biotic stress (living) • Abiotic stress (non-living) 8.2 Abiotic stress

• Abiotic stress is defined as:“The negative impact of non-living factors on the living organisms in a specific environment”

• Only 10% of the world arable land may be categorized as free from stress.

8.2.1 Type of abiotic stress

8.2.1.1 Temperature stress

• Temperature is one of the most important components of climate. It plays vital role in the production of horticultural crops.

• The different activities of plant like growth and development, respiration, photosynthesis, transpiration, uptake of nutrients and water and reproduction (Such as pollen viability, blossom fertilization fruit set etc.), carbohydrate and growth regulators balance, rate of maturation and senescence, and quality, yield and shelf life of the edible products.

• The above function of the plant should be well when the temperature at the optimum range.During high temperature plant does not perform proper functions of growth, where in low temperature physiological activities of the plant are stopped.

Introduction

• India is the second largest producer of fruits in the world after China

• India is rich in fruit diversity starting from tropical, subtropical to temperate region.

• Some of the fruits like Guava, pomegranate, lemon, mandarin etc., if left without any treatment, give several light harvests of the variable quantities and qualities from the various flowering flushes throughout the year.

• Some of the fruit crops bloom throughout the year without any resting period and produces two or three crops (bahar) in a year but yield and quality is not so good in all crop harvest. So, it is very essential to understand the flowering and fruiting behavior of crops and which bahar will give good crop with considering all the factors associated with a particular bahar.

7.1 What is crop regulation?

• Crop regulation means to force the tree for its rest and to produce blossom and fruits during any one of two or three flushes”

• Crops in which flowering is continuous throughout the year; economic yield cannot be achieved in any of the season.

• Therefore, by analyzing market demand flowering can be forced in particular one season, which gives the economic yield.

• Through various techniques like cultural practices and chemical treatments, trees are thrown to rest prior to flowering and then practices are done to trigger flowering.

• Thus, crop regulation is a method to regulate flowering by altering natural tendency of the tree by artificial means.

6.1 Scenario in precision farming

• India’s population is around 1366 million by 2020 which requires food grain production of 350 million tones.

• Considering the current food grain production levels, India needs to raise food grain production levels by not less than 4.00 per cent per year. As the availability of land has decreased, application of fertilizers and pesticides become necessary to increase food production.Indiscriminate use of inputs coupled with improper management practices over a long period has resulted in decline in soil productivity.

• Agriculture production system is outcome of interaction of various agro inputs. Therefore, judicious management of these inputs is necessary for the sustainability of these inputs.

• In our agriculture systems, spatial variability over the landscape is ignored and fertilizers, herbicide, pesticides, fungicides etc. are applied at uniform rate over the whole field.

• It has been recognized that crops and soils are not uniform within a given field. The management of in-field variability in soil fertility and crop conditions for improving crop production and minimizing the environmental impact is the crux of precision farming.

• Definitions • It is defined as the application of technologies and principles to manage spatial and temporal variability associated with all aspects of agricultural production (Pierce and Nowak, 1999).

• It is an integrated information and production-based farming system that is designed to increase long term, site specific and whole farm production efficiency, productivity and profitability while minimizing unintended impacts on environment.

5.1 Crop modelling

• Crop model

• “Schematic representation of the system’’i.e. a model as defined by De Wit 1970.

• Such a model can be based on statistics applied to a set of experimental data or on physical laws (Guyot, 1997).e.g. Irrigation is able to satisfy a crop’s water needs provided its management relies on the measurement or estimation of evapotranspiration. The manager can either invest in equipment to monitor changes in water content in the soil or fluxes of water into the plant or the atmosphere, or rely on a ‘‘schematic representation of the system’’, i.e. a model.

• In very simple terms we can define a crop model as “a well-thought out plan of activities to grow the desired crop to get maximum possible yields of high-quality produce with the given resources. It can be a mental or a written exercise (a “schematic representation of the system”) that a farmer or a farm manager prepares for a crop or for an individual crop”.

• In other words, we can also say that a model is “an attempt to describe a certain process or system through the use of a simplified representation, preferably a quantitative mathematical expression, that focuses on a relatively a few key variables that control the process or system”.

• It is clear that in finalizing a crop model we have to assume some mean or standard values (based on the past record, experience, expert judgment, etc.) of the variables which we may not be taking explicitly in our model.