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Only a very brief mention of various basic aspects of plant nutrition is given here. Associates wanting to know more details should refer to any one of the standard Plant Nutrition publication (PRINCIPLES OF PLANT NUTRITION by K. Mengel and E.A. Kirkby).

Increased production of food and cash crops is the need of our times; as land and irrigation water are limited and beyond any means of expansion. Crop yields per unit input should increase. Crop yield under natural production systems is limited by the availability of nutrients in the soil. Unless the supply of nutrients can be enhanced yields cannot be high.

Although the application of fertilizer to even fairly fertile soils can give a great increase in crop yield, soil fertility is not simply a matter of nutrient content. It is dependent on a number of complex of issues:

Soil depth

The volume of soil from which the crop draws its nutrition varies according to the rooting depth of the crop. However hard or rocky layers can restrict natural root development; this is particularly the case with micro irrigation systems.

Soil structure

Particle size and soil aggregate size and distribution, effect the size and distribution of pores and therefore the availability of air and water to the roots.

Knowledge of fertilizer dose, selection of fertilizer sources, time and method of application is essential for achieving efficient use of fertilizers and profitable yield.

A. Fertilizer Dose

Fertilizer dose for crops is determined based on the field experimentation. It varies with the crops and varieties, initial fertility of the soil, soil properties, cropping system, climate, season, rainfed or irrigated crop, expected yield etc. Fertilizer dose for rainfedcrops (Kg/ha)

The term Rainfed agriculture is used to describe farming practices that rely on rainfall for water. It provides much of the food consumed by poor communities in developing countries. In India, about 52% of total net sown area comes under rainfed lands. Rainfed crops account for 48 per cent area under food crops and 68 per cent under non-food crops. India ranks first among the rainfed agricultural countries of the world in terms of both extent and value of produce. Due to population pressure on agricultural lands, the poverty is concentrated in rainfed regions. The climate in India’s rainfed regions is characterized by complex climatic deficiencies, manifested as water scarcity for rainfed crop production. The climate is largely semi-arid and dry sub-humid with a short (occasionally intense) wet season followed by long dry season. Rainfall is highly unreliable, both in time and space, with strong risks of dry spells at critical growth stages even during good rainfall years. The fluctuations are due to numerous factors affecting the monsoonal climate including the atmospheric circulation and strong links to El-Nino Southern Oscillation (ENSO) phenomenon in the Pacific Ocean.

Rainfed areas in India are highly diverse, ranging from resource rich areas to resource-constrained areas. Some of the resource rich areas are highly productive and have experienced widespread adoption of technology. However, most of the areas are resource constrained and dry areas. In the resource constrained and dry areas, the farming is a survival mechanism rather than a growth oriented activity. Rainfed agriculture is practiced under a wide variety of soil type, agro-climatic and rainfall conditions ranging from 400 mm to 1600 mm per annum. Rainfed Crops are prone to breaks in the monsoon during the crop growth due to water stress. This water stress may be due to variability of rainfall, delay in sowing, diversity in crop management practice and variability of the soil type. The prolonged breaks can result in partial or complete failure of the crops.

Strategies To Improve The Productivity Of Drylands

With renewed interest in rainfed agriculture during 1970s, both the national (AICRPDA and CRIDA) and international institutions (ICRISAT) have studied several aspects of rainwater management. Recommendations have been made after their through testing both at the research stations and on farmer’s fields. Initially these technologies were accepted by the farmers because of the pursuasion by the Scientists and the incentives, but many of them are forgotten once the support is withdrawn. It is now time for us to examine whether the technologies themselves were weak or certain components were missing. Malfunctioning of the software may be due to a bug right from the beginning or it entered into the system at a later stage. It is also possible that we neglected certain critical inputs which became major constraints making the system defunct. Whatever the reason it should be identified and set right if the technology has to continue as tool for tackling the challenges of rainfed agriculture.

ESSENTIAL ELEMENTS FOR PLANT GROWTH

Arnon (1954) set three criteria to state an element is essential to plants. They are:

1. The plant must be unable to grow normally or complete its life cycle in the absence of the element,
2. The element is specific and cannot be replaced by another and,
3. The element plays a direct role in metabolism.

Accordingly there are 16 elements essential for plant growth. They are carbon, hydrogen and oxygen called primary nutrients, calcium, magnesium and sulphur called secondary nutrients; iron, zinc, manganese, copper, boron, chlorine and molybdenum are known as micronutrients.

Plants are the generators or the primary source of organic matter while animals are the transformers- secondary source of organic matter. In agriculture, plants add 10–30 percent of organic matter through their roots stubbles and leaf fall and exudations. The excreta of livestock, the organic wastes of urban and rural residential areas include the garbage and sewage and sludge. The by products of agro based industries viz. bagasse, vinasse, pressmud from sugar industries, the coir dust from the coir industries, dust of cotton from ginning industries, the fruit and food processing industries wastes.

Integrated plant nutrition system conceptualized by food and agriculture organization is the maintenance or adjustment of soil fertility and of plant nutrient supply to an optimum level for sustaining the desired productivity through optimization of benefits from all possible sources of plant nutrients viz. organic manures, fertilizers, crop residues, compost or nitrogen fixing crops etc. in an integrated manner.

R software is a programming language used for statistical analysis, graphical representation and reporting, and is currently developed by the R Development Core Team. R software is available freely under the GNU General Public License, and the binary versions are provided for the Windows, Linux and Mac operating systems. To develop R, effort from all over the world is made in a collaborative manner.

What is GNU?

GNU stands for GNU’s Not Unix. It is a Unix like computer operating system, but different from Unix. GNU consists of GNU packages which are program specific and released by GNU project. Free software means that the users of the software have freedom to run and use the software and also can copy, change, improve and distribute the software freely.

Development of R

R software was initially written by Robert Gentleman and Ross Ihaka also known as “R & R” of the statistics department of the University of Auckland, New Zealand. R appeared first in 1993. Since then various contribution to R has been made by a large group of talented individuals by sending code and bug reports. A core group, known as the “R Core Team” modify the R source code archive since 1997. Thus R is a collaborative project with many contributors.

Soil fertility depends on the physical, chemical, and biological properties of the soil. Among the biological properties, soil enzymes are used as an index of soil fertility. Soil enzymes respond to changes in soil management faster in comparison to other soil variables, and also catalyze the reactions necessary for the life processes of microorganisms in soils. The biochemical reactions are brought about by the catalytic action of enzymes. Soil enzymes include amylase, phosphatase, urease, cellulase, protease, glycosidase, and arylsulfatase. They play a role in organic material decomposition, the transformation of organic matter, nutrient cycling, nitrogen fixation, detoxification of pesticides, xenobiotics, etc., and thus regulate the ecosystem.

Depending on their location, enzymes can be extracellular or intracellular. Intracellular enzymes are found in the cell’s cytoplasm or bound to the cell walls of living and metabolically active cells. Extracellular enzymes released into the soil and are “permanently” immobilized on clay and humic colloids via ionic interactions, covalent bonds, hydrogen bonding, entrapment, and other mechanisms. There are two kinds of soil enzymes.

Soil microorganisms are the most important agents in the cycling or transformation of various elements (N, P, K, S, Fe etc.) in the biosphere; where the essential elements undergo cyclic alterations between the inorganic state as free elements in nature and the combined state in living organisms. Life on earth is dependent on the cycling of nutrient elements from their elemental states to inorganic compounds to organic compounds and back into their elemental states.

The microbes through the process of biochemical reactions convert / breakdown complex organic compounds into simple inorganic compounds and finally into their constituent elements. This process is known as “Mineralization”.

Mineralization of organic carbon, nitrogen, phosphorus, sulphur, and iron by soil microorganisms makes these elements available for reuse by plants. In the following paragraphs the cycling or transformations of some of the important elements are discussed.

Phosphorus is only second to nitrogen as an inorganic nutrient required by both plants and microorganisms. It stimulates growth of young plants, giving them a good and vigorous start. Phosphorus management and nutrition has both economic and environmental implications. Phosphate constitutes nearly 0.1% of the earth’s crust. They occur in soil in inorganic and organic forms. The organic phosphorus containing compounds are derived from plants and microorganisms and are composed of nucleic acids, phospholipids, lecithin, phytin and related compounds. In soil, 15-85 % of the total P is organic and soils rich in organic matter contain abundant organic P. The inorganic forms are derived from parent rocks or through fertilizers application and manuring with bone meal. They are soluble in water when present as phosphates of Na, K, Ca, Mg etc. Phosphorus exists mainly as apatites, with the basic formula M₁₀ (PO₄) ₆ X₂. Commonly the mineral (M) is Ca, less often Al or Fe. The anion (X) is either F^-, Cl^-, OH^- or CO^2- ₃. Diverse combinations of M and X results in 200 forms of P.

It is a major constituent of nucleic acids in all living systems essential in the accumulation and release of energy during cellular metabolism. This element is added to the soil in the form of chemical fertilizers, or in the form of organic phosphates present in plant and animal residues. In cultivated soils it is present in abundance (i.e. 1100 kg/ha), but most of which is not available to plants, only 15 % of total soil phosphorus is in available form. Both inorganic and organic phosphates exist in soil and occupy a critical position both in plant growth and in the biology of soil.

Microbial transformations of sulfur (S) are even more complex than those of nitrogen because of the large number of oxidation states of S and the fact that several transformations of S also occur abiotically. Although a number of oxidation states of S are possible, only three are significant in nature, 2 (sulfhydryl, R–SH, and sulfide, HS-), 0 (elemental sulfur, S0), and 6 (sulfate, SO₄ 2-). The bulk of S Earth’s S is in sediments and rocks in the form of sulfate minerals, primarily gypsum (CaSO₄) and sulfide minerals (pyrite, FeS2), but the oceans constitute the most significant reservoir of SO₄ ^2- in the biosphere. A significant amount of S, in particular sulfur dioxide (SO₂), enters the S cycle from human activities, primarily the burning of fossil fuels.

Hydrogen Sulfide and Sulfate Reduction

A major volatile S gas is hydrogen sulfide (H₂S). Hydrogen sulfide is produced from bacterial sulfate reduction or is emitted from sulfide springs and volcanoes. Although H₂S is volatile, different forms exist depending on pH: H₂S predominates below pH 7 and the nonvolatile HS- and S^2- predominate above pH 7. Collectively,H₂S, HS, and S₂ are referred to as “sulfide.” Sulfate-reducing bacteria are a large and highly diverse group and are widespread in nature. However, in anoxic habitats such as freshwater sediments and many soils, sulfate reduction is SO₄ ^2- limited. Moreover, because organic electron donors (or H₂, which is a product of the fermentation of organic compounds) are needed to support sulfate reduction, it only occurs where significant amounts of organic material are present.

The spermosphere represents a short-lived, rapidly changing, and microbiologically dynamic zone of soil surrounding a germinating seed. It is analogous to the rhizosphere, being established largely by the carbon compounds released into the soil once the seed begins to hydrate. These seed exudations drive the microbial activities that take place in the spermosphere, many of which can have long-lasting impacts on plant growth and development as well as on plant health.

Soil is the largest terrestrial ecosystem where a wide variety of relationships exists between different types of soil organisms. The associations existing between different soil microorganisms, whether of a symbiotic or antagonistic nature, influence the activities of microorganisms in the soil. Microflora composition of any habitat is governed by the biological equilibrium created by the associations and interactions of all individuals found in the community. In soil, many microorganisms live in close proximity and interact among them-selves in a different ways. Some of the interactions or associations are mutually beneficial, or mutually detrimental or neutral.

Chemical pesticides though extremely effective in controlling pest population suffer from disadvantages. They have a broad toxic range and potentially toxic to non target organisms. Other constraints that have emerged with the use of chemical pesticides such as development of resistance and resurgence in insects, residual toxicity, secondary outbreak of minor insect pests, etc., In this juncture, the biopesticides have proven to be effective tool in managing the devastating insect pests of various crops.

The biopesticides are types of pesticides derived from natural materials such as microorganisms, plants, animals and certain minerals. They are living organisms or their products or byproducts, which can be used for the management of pests that are injurious to crop plants. Biopesticides have a vital role in crop protection, although most commonly in combination with other tools including chemical pesticides as part of integrated pest management (IPM). Microorganisms help to regulate the abundance of many pests or potential pests without any cost to society. Microbes can be increased artificially and thereby achieve faster, higher and more consistent control of the target pests that will occur naturally. Insect pathogens that are transmissible in nature from one host to another offer an important bonus effect that chemical insecticides do not have. A pathogen will kill pests exposed and many continue killing them by natural transmission from one individual host to another through subsequent host generation.

Biopesticides generally have several advantages compared to conventional pesticides. While chemical pesticides are responsible for extensive pollution of the environment, a serious health hazard due to the presence of their residues in food and development of resistance in targeted insect pest populations, biopesticides, in contrast, are inherently less toxic to humans and the environment, do not leave harmful residues, and are usually more specific to target pests. The agents employed as biopesticides, include parasites, predetors and disease causing fungi, bacteria and viruses, which are the natural enemies of pests. Utilization of naturally occurring parasites, predators and pathogens for pest control is a classical biological control. These bio agents can be conserved, preserved and multiplied under laboratory condition for field release. Once these bio-agents are introduced in the field to build their population considerably, they are capable of bringing down the targeted pest population below economic threshold level (ETL).

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

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

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

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

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

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

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

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

C₃ cycle or Calvin cycle: It is a process of dark reaction of photosynthesis. It is also called as photosynthetic carbon reduction cycle which results in the production of sugars. It occurs not only in C₃ plants but also in C₄ and CAM pathway also. It occurs in the mesophyll cells. It is described in three stages: (1) Carboxylation, (2) Reduction, (3) Regeneration.

C₃ plants: Group of plants with calvin cycle wherein the first stable product is 3-phosphoglyceric acid, a three carbon compound. e.g., rice, wheat, barley.

C₄ cycle: C₄ cycle may also referred to as the dicarboxylic acid cycle or Hatch and Slack Cycle. The first stable product is a C₄ compounds like oxaloacetic acid. Here CO₂ molecule is accepted by phosphoenol pyruvate in the carboxylation reaction. The main purpose of this cycle is carbondioxide enrichment.

C₄ plants: Plants with Hatch-slack pathway and kranz anatomy of leaves in which the first stable product is four carbon compound, oxaloacetic acid. These plants posses high photosynthetic efficiency and low photorespiration rate. e.g., sugarcane, maize, sorghum.

Predation and cannibalism are entirely two different processes. In predation, the animal used to consume other species then their own, whereas cannibalism is a practice of eating one’s own kind. Cannibalism is a common behavior in animal kingdom and has been recorded in more than 1500 species. It is reported in an increasing number of fish species belonging to group/ families such as air-breathing catfishes (Clariidae), pikes (Esocidae), percids (Percidae), characids (Characidae), latids (Latidae), gadids (Gadidae) and in over 30 other families, including cyprinids (Cyprinidae) and salmonids (Salmonidae) (Smith & Reay, 1991; Hecht & Peinaar, 1993; Folkvord, 1991; Baras, 1998; Qin et al., 2004). Cannibalism is a common ecological interaction and depends on genetics and fish behavior; mediated by appetite and metabolism and is promoted by size differences, and is more intense among fast growing larvae and young juveniles than among older fish (Hecht and Pienaar, 1993; Baras, 1998).

Cannibalism is a serious problem in the farming of striped murrel that starts from the early larval stage (Ng and Lim, 1990) and continues at all sizes including during parenting also. Murrels have large mouth gape; sharp jaw teeth for catching & grasping prey and can consume prey fish more than half to two-third of its length (Wee, 1981; Diana et al., 1985; Ng and Lim, 1990 and Qin and Fast, 1996). Its aerodynamic body shape allows fast movement in water and catching the prey with ease. Striped murrel observes two types of cannibalism, Filial and Intracohort, which is discussed in detail in the subsequent sections.

Stocking fingerlings in grow-out ponds increases survival rates, cut-down culture duration, better feed management and reduce risk-factors on account of natural as well disease occurrence. In pond culture, good amount of fry-size seed suffer predation from enemies such as snakes, birds and predator fishes, if any and mortalities due to disease occurrence as smaller size fish is more vulnerable. However, fingerling stocking reduces predation loss to a greater extent, increase survivals, allow better feed management and highe production. This is truer with carnivorous fishes and particularly those observe cannibalism. Qin and Fast (1996) stated that the rate of cannibalism is higher in small size (TL) predators than the larger in case of striped murrel, so stocking large size fingerling in culture ponds reduces chances of ICC and hence recommended for grow-out production.

7.1 Traditional Methods of Fingerling Rearing

Wee (1981) has defined traditional system of murrel farming in Thailand in which seed of murrel was procured from wild resources and raised to large fingerling size before stocking. Two type of practices being used to raise fingerlings. In the first one, the pond(s) designated for fingerling production are stocked with brooders of SFs so they could spawn in the stocking pond(s) few days before the stocking of striped murrel fry and could directly feed upon the juvenile SFs. In second system, the fingerlings were reared to accept small-size fish (SF) along with rice bran to cut down cost of feeding on production of fingerling. In recent, more systematic approaches have been made to wean the seed collected from the wild resources on inert diets totally. The protocol adopted for weaning the fingerling on inert diet includes initial feeding with cut pieces of SFs and then gradual supplementation of inert diet till fingerlings start relishing inert diet completely.

Introduction

Resource Conserving Technology refers to any management approach or technology that increases factor productivity including land, labour, capital and inputs. The resource conserving technologies (RCTs) involving no or minimum tillage, direct seeding, bed planting and crop diversification with innovations in residues management are the possible alternatives to the conventional energy and input-intensive agriculture. The RCTs with innovations in residue management avoid straw burning, improve soil organic C, enhance input efficiency and have the potential to reduce GHGs emissions (Pathak et al., 2011). Conservation agriculture is one the effective Resource Conservation Technologies, which is based on three principles which are minimum soil disturbance, maintenance of permanent soil covers by the use of crop residues and cover crops and diverse plant associations which included crop rotations. Globally, Conservation Agriculture is being practiced in about 125 M ha area. USA with 26.5 M ha contributes to the major CA-practicing countries followed by Brazil (25.5 M ha), Argentina (25.5 M ha), Canada (13.5 M ha) and Australia (17.0 M ha). However, in the context of climate change to increase the production and productivity, India’s CA adoption is still in preliminary phases in area of 1.5 million ha with adoption of Zero Tillage (Jat et al., 2012, www.fao.org/ag/ca/6c.html). The major CA-based technologies being adopted is zero-tillage (ZT) wheat in the rice-wheat system of Indo-Gangetic Plains.

Introduction

Persistent income from agriculture is most important for sustaining the farming sector. Conservation agriculture (CA) is a resource-saving agricultural production system that aims to achieve production intensification and high yields while enhancing the natural resource base through compliance with three interrelated principles, along with other good production practices of plant nutrition and pest management (Abrol and Sangar, 2006). Conservation agriculture is largely promoted as one of the few win–win technologies affordable to farmers, in the sense that potentially it improves farmers’ yields (in the long term) at the same time conserving the environment. CA is described by FAO (http://www.fao.org.ag/ca) as a concept for resource saving agricultural crop production which is based on enhancing the natural and biological processes above and below the ground. As per FAO definition CA is to a.) Achieve acceptable profits, b.) High and sustained production levels, and c.) Conserve the environment. It aims at reversing the process of degradation inherent to the conventional agricultural practices like intensive agriculture, burning/removal of crop residues. Shifting from tillage-based agriculture to no-tillage CA systems removes unsustainable elements in the current tillage based systems and replaces them with CA elements that make the production systems profitable and ecologically sustainable. Conservation agriculture offers an opportunity for arresting and reversing the downward spiral of resource degradation, decreasing cultivation costs and making agriculture more resource – use-efficient, competitive and sustainable.

In modern agriculture, use of synthetic chemical fertilizers are essential in agriculture for sustainable yield but, these have resulted in environmental pollution. The use of synthetic fertilizer could result in serious human health issues and also affects the soil microflora, besides being costly due to high production cost. Further, excess use affects soil processes and result in nutrient imbalances in plants with increased susceptibility to pests and diseases and also affects the symbiotic associations. Under these circumstances, biofertilizers could be an alternative for integrated nutrient management system in horticulture. The entire crop production system depends on soil beneficial microflora and their activities, which makes them highly potential alternatives to synthetic chemical fertilizers.

Biofertilizers or microbial fertilizers are essential for eco-friendly and sustainable cultural practices. The term “biofertiliser” has been defined in several ways due to its unique relationships between the plant and rhizosphere microflora. Biofertilizers mainly include nitrogen fixing bacteria, phosphate solublizing and potash solubiling bacteria.

The soil fertility is depleting in the current scenario of gap between nutrient removal from soil and supplies. Moreover, increase in the fertilizer prices has become unaffordable to small and marginal farmers. There is also a growing concern about the environmental hazards and its threat to sustainable crop production. Indiscriminate use of synthetic fertilizers for intensive crop production has resulted in large quantity of nutrient (particularly P) accumulation in soils which has resulted in generating a dead soil. In this context, the long term use of biofertilizers are considered to be economical, eco-friendly, more efficient, productive and accessible to marginal and small farmers over chemical fertilizers (Subba Rao, 2001). Biofertilizers mainly consists of specific living cells which supplies nutrients to plants through their root system. Microbes in these fertilizers provide nutrients to the plants by nitrogen fixation, phosphate solubilization, phosphate mobilization, and promotion of beneficial rhizobacteria (Bhat et al., 2010). Biofertilizer application improves the supply of nutrients, organic carbon, accumulation of soil enzymes, productivity, soil fertility index, economy of farmers, and maintenance of sustainability in natural soil ecosystem and horticultural crops. The production of efficient and sustainable biofertilizers for crop plants needs to be undertaken to make the biofertilizers popular and efficient. The important and specific research in future may be focused on the following aspects.

Bone is an integral part of musculo-skeletal system of body. In the living animal it is bluish pink, whereas, fresh dead bone is yellowish-white in colour. It is hard and resistant to pressure but also have certain amount of elasticity. Its tensile strength is equal to the cast iron, though bone three times lighter and ten times flexible to cast iron.

Number of bones: The number of bones of the skeleton varies with age and species. Number of bones in cattle-210; Horse-208; Dog-271; Fowl-166 and human-208 (207-212)

Composition of bone: Bone contains different bone cells, organic and inorganic matrix and water. Organic matrix is about one-third and Inorganic matrix is two-third weight by volume. The organic material consists of 90% collagen [type-I (maximum), type V and type XII] and 10% non-collagenous glycoprotein and bone specific proteoglycans (osteocalcin, osteonectin, sialoprotein, bone phosphoproteins and small proteoglycans) and bone growth factors [TGF-beta family; Insulin-like growth factor-1, 2; bone morphogenetic protein (BMP); platelet derived growth factor (PDGF); Interleukin -1 (IL-1); Interleukin-6 (IL-6); colony stimulating factor]. Organic matrix of bone resembles the matrix of dense fibrous tissues such as tendons, ligament and joint capsule. It is not certain whether all of these proteins are synthesized by bone cells or whether they are synthesized by cells outside of the bone and then incorporated into the bone matrix. However, their presence within bone and their potential to affect the activity of bone cells suggests they have important role in controlling bone cell functions. Inorganic matrix of bone or mineral component of bone serves as an ion reservoir and gives bone of its stiffness and strength. It reserves 99% of body calcium, 85% body phosphorus and 40-60% body sodium and magnesium. Inorganic matrix of bone is composed of 85% calcium phosphate, 12% calcium carbonate, 3% of magnesium phosphate, calcium fluoride and magnesium carbonate. It also contains traces of chlorine, sodium, potassium. These minerals remain as hydroxyapatite crystal form within bone. However, bone mineral crystal is not pure hydroxyapatite, instead they contain both carbonate and acid phosphate groups (HPO₄) and bone crystal does not contain OH groups. Bone matrix has such great durability and stability that it can remain essentially unchanged and retain much of its strength for centuries after death. Removal of organic matters renders the bone fragile, brittle and shattered, whereas, decalcification renders bone soft and pliable and resistant to fracture.

Fracture healing is a specialized type of a wound healing response in which the regeneration of bone leads to a restoration of skeletal integrity. Because healing of a fracture in a living organism is accomplished by cells, it can be modified by almost any endogenous or exogenous factors like nutrients, vitamins, hormones, growth factor etc. that has an influence on the metabolic function of bone cells. Fracture healing may be induced by malnutrition that involves certain nutrients, notably calcium (Ca), phosphorus (P) and vitamin D, but also iodine (I), copper (Cu), zinc (Zn), manganese (Mn), fluorine (F), silicon, vitamin A and perhaps vitamin C as well as different endocrines. The number of these nutrients and their interaction is so large that dietary intervention in fracture management is likely to be the most effective if directed at consumption of a good diet that is completely balanced for growth, maturity, old age or stress. Substitution of a good diet for a bad one is also likely to be more convenient and safer than most attempts at partial supplementation of a faulty diet in order to bring it into balance. Underfeeding a good diet decreases size-for-age of bones during growth and delayed fracture healing. Underfeeding may engender osteoporosis in older animals. Underfeeding of Ca, P and vitamin D, causes delayed fracture healing. Over feeding a balanced diet induces rapid growth of newly formed bone and sometimes-accelerated fracture healing but it also causes obesity in adults.

Three major component of bone are osteogenic cells, organic matrix and inorganic matrix (mineral). The osteogenic cells include osteoblasts, osteocytes and osteoclasts, while the matrix consists predominantly of collagen and proteoglycans and constitutes approximately one-third of bone mass (on dry basis). The inorganic/mineral component that makes up approximately two-third of bone and it performs two essential functions : it serves as an ion reservoir and it gives bone most of its stiffness and strength. Bone is a reservoir for 99% of body calcium, 85% of body phosphorus and 40-60% of body sodium and magnesium. The main mineral composition of a long bone is: 85% calcium phosphate as hydroxyapatite, 12% calcium carbonate and 3% magnesium phosphate, calcium fluoride and magnesium carbonate and trace amount of chloride, potassium and sodium. For collagen synthesis, hydroxylase enzymes requires ferrous ion and vitamin C. Impaired collagen synthesis also occurs during deficiencies of vitamin D and E and zinc. The organic intercellular bone matrix is rich in mucoplysaccharide. Their synthesis involves enzymes that require manganese, zinc and vitamin A.

Bone differs from other tissues not only in physio-chemical structure, but also in its extraordinary capacity for growth, continuous internal remodelling and regeneration throughout post fetal life. Bone formation is a complex process regulated by diet, vitamins, hormones and growth factors. Growth factors are polypeptides that increase cell replication and have important effects on differentiated cell function. Growth factors are initially considered as systemic agents, but current evidence indicates that they act primarily as local regulators of cell growth. The transforming growth factor-β family of proteins, which comprises polypeptide growth factors that have diverse effects on the growth, differentiation, and function of cells, is receiving considerable attention for potential clinical applications and is likely of physiological and orthopedically significance.

Transforming growth factors

It is one of the most important growth-promoting osteo-inductive substances, which have been identified at the site of fractures and other places. Transforming growth factors (TGFs) have been categorized into TGF-β (alpha) and TGF-β (beta). TGF-α has not been isolated from bone tissue and cannot be considered a local regulator of bone remodelling, although it is mitogenic for bone cells and stimulates bone resorption. TGF-α shared amino acid sequence, receptor-binding and functional activity with epidermal growth factors but had only weak transforming growth factors activity. Furthermore, TGF-β by itself is completely ineffective, but together with TGF-α, it potently induced growth of colonies of cell-line.

The knowledge and principles from interconnected disciplines of bioengineering, material science and life sciences are combined in tissue engineering with the aim of developing a construct, that can wholly or partly restore/maintain/augment the function of a damaged tissue or organ. Tissue engineering construct generally comprises cells on a suitable scaffold. The ultimate functionality of a tissue engineering construct is mainly dependent on the cell behavior on scaffolds. The proliferation and cell viability on scaffolds varies from one cell type to another and from one species to another. So it is important to investigate individual cell-scaffold combinations. The similarity in structure and composition to bone mineral, osteoconducive properties, ability to integrate with the bony tissue and absence of immune response makes hydroxyapatite [Ca₁₀ (PO₄)₆(OH)₂] the choice of calcium phosphate biomaterial with only disadvantage of slow rate of resorption. On contrary, silica–calcium phosphate composite in comparison to calcium phosphate is rich biomaterials having a faster resorption rate. Studies have shown that coating of hydroxyapatite with a calcium silicate containing layer encourages cell proliferation and osteogenic differentiation of human bone marrow-derived stromal cells. So in this chapter, a triphasic composite scaffold (calcium silicate, hydroxyapatite and tricalcium phosphate), namely HASi with elements in the following percentages: 66.36 % - calcium, 25.35 % - phosphorus and silicon - 8.29 % and porosity of 50 – 500 µm is reported to evaluate the rBMSC proliferation and differentiation properties in vitro.

The present chapter is therefore, included with the aim of assessing cytocompatibility of HASi and rBMSC in terms of cell attachment, cell morphology, cell proliferation and osteogenic differentiation.

Fracture healing is a specialized type of wound healing response in which the regeneration of bone leads to restoration of skeletal integrity. Though the process of fracture healing is usually considered to be biologically optimum; the healing of 5-10% is delayed or impaired. For management of these types of fractures, use of biological methods for the enhancement of fracture healing is essential. Furthermore, fracture-healing can be modified by almost any endogenous or exogenous factor that has an influence on the metabolic function of cells. These factors include transforming growth factor-beta, bone morphogenetic proteins, hormones, vitamins, prostaglandin and calcium containing feed supplement medicine.

Keeping in view the above, in this chapter, efficacy of herbal product-Magacal in promoting osteogenesis during fracture healing in experimental animals is discussed. Magacal optimizes absorption, bioavailability and utilization of dietary calcium, phosphorus and magnesium. It is claimed to have advanced chelating agent to form organic complex chelate with dietary Ca, P and Mg, besides containing natural Vitamin D metabolites in highly bioavailability organic form, naturally protected and stable biotin and modern delivery system for optimum translocation of Ca, P and Mg ions to the sites of requirements.

Clinically healthy, adult New Zealand White rabbits of either sex (10) are divided equally into two groups A and B each consisting of 5 animals. All animals are kept on standard diet and management throughout the experiment. In all animals, midshaft simple transverse fracture is created in both the ulnae under thiopental (2.5%) anaesthesia. In test group (Group A), Magacal is given @5ml/animal/ day, orally from day 5-20 post fracture, whereas, in group B, no drug is given which serve as control. Antibiotic dressing of the skin wound is done daily for one week with povidone iodine and himax ointment. All the animals are administered streptopenicillin @ 0.5 gm/animal/day for 5 days postoperatively. Skin sutures are removed on the10th postoperative day.

Clinically all the animals are observed for inflammation, pain and edema at the fracture site, surgical wound healing, appetite, general health, muscular atrophy of the limb, if any, at different intervals postoperatively.

Minimally invasive percutaneous osteosynthesis (MIPO), or minimally invasive fracture repair, was introduced into human orthopedic surgery during the 1990s because of several distinct advantages over traditional open reduction techniques. In MIPO, large incisions to facilitate open reduction are avoided and implants are introduced through small stab incisions in the skin. This led to advent to more biology friendly techniques. These biological techniques lay stress upon maximal preservation of blood supply around the fractured bone by minimal direct handling of the fracture environment. MIPO offer advantages which include preservation of the fracture hematoma; less surgical trauma to the surrounding soft tissues, reduced operative time therefore, decreased risk of infection and ultimately leading to indirect bone healing with abundant callus. Minimally invasive plate osteosynthesis (MIPO) is a novel technique for application of principles of biological fracture healing with a philosophy of dealing with soft tissues with utmost respect. Following advancements in implant technology and development of techniques of indirect fracture reduction this technique gained more popularity. The evolution of MIPO began with the use of bridge plating. Initially a conventional plate is applied for comminuted femoral fractures using long incisions but with preservation of the vastus lateralis muscle resulting in healing with abundant callus. Subsequently, the size of incisions got decreased, rather two small incisions are given at proximal and distal ends and plates are bridged sub muscularly over the fracture fragments. This technique causes minimal distress to soft tissues and bone, provides access to the bone through soft tissue windows, with minimal or no contact with the fracture by indirect reduction tools and leaving behind minimal foot prints.

One of the most common fractures seen in the dog is comminutuion of femoral shaft, often related to sever impact from an automobile accident or jump from a height. Comminuted fractures are characterized by one or more butterfly fragments and assorted small bone chips that are especially difficult to align accurately and stabilize completely. These complicated fractures require sophisticated repair technique that are capable to resisting compression, bending and rotational forces. Rebuilding of comminuted fractures so that all fragments are accurately aligned and gaps are eliminated is often impossible. Non-union and osteomylitis have their highest incidence in these fractures. Over the years, several techniques are tried to treat comminuted femoral fractures with different success rate and there is a lack of uniform fracture presentation. Hence, it will be difficult to compare different techniques in a particular type of fracture. The present chapter is, therefore, undertaken to evaluate radiographically and histopathologically the efficacy of three different internal fixation techniques in the management of comminuted diaphyseal femoral fracture in dogs.

Clinically healthy, adult mongrel dogs (15) of either sex are randomly divided into groups A, B and C of 5 animals each. In all the animals unilateral comminuted diaphyseal femoral fractures is created under general (thiopental - 5%) anaesthesia and is immobilized with intramedullary (IM) pinning with cerclage wiring (Gr. A), neutralization bone plating (Gr. B) and neutralization bone plating with cerclage wiring (Gr. C) respectively. All the animals are administered broad spectrum antibiotic (streptopenicillin @ I g intramuscularly (dog/day) and analgesic (diclophenac sodium @ l mg/ kg b. wt. daily) and surgical wounds are dressed daily with povidone iodine and antibiotic cream for 5 days postoperatively.

Lateral and oblique views of radiography are taken at the operated site just after the operation and subsequently on days 15, 30, 45 and 60 postoperatively. The radiographs are observed for status of fracture reduction and fixation, progress of healing at the fracture site and complications like fixation failure, osteomylitis etc., if any, at different intervals. Bone sections are collected from the fracture site including adjacent normal bone after sacrificing the animals on day 60. The sections are decalcified using Goodling and Stewart’s solution (80% distilled water, 15% formic acid and 5% formalin) and then processed routinely for H & E staining for histopathological studies

Healing of fracture is a consequence of cellular behaviour in a living organism and as such can be modified by almost all endogenous or exogenous factors that affect the metabolic function of cells. These factors include transforming growth factor-β, bone morphogenetic proteins, hormones, vitamins and prostaglandins. The anabolic hormones like thyroxine and insulin accelerate bone formation in experimental animal. Hence, this chapter is proposed to evaluate the effects of thyroxine and insulin therapy in the management of tibial metaphyseal fracture in dogs.

Clinically healthy, adult mongrel dogs (15) of either sex are randomly divided into three groups (A₁, A₂ and A₃) of 5 animals each. In all the animals, unilateral metaphyseal fracture is created in the proximal tibia and then immobilized with cross intramedullary pinning with interfragmentary wiring under thiopental (5%) anaesthesia. All the animals are administered broad-spectrum antibiotic (streptopenicillin @ 1 g intramuscularly /dog/day) and analgesic (5 ml I/M daily) and surgical wounds are dressed daily with Povidone iodine and Lorexane cream for 5 days postoperatively. In group A₂, thyroxine sodium tablets (0.013 mg/kg body wt, orally) and in A₃, insulin injection (2 IU/kg body wt, s/c) are given on day 7 and then on every alternate day till day 45 postoperatively, at one specific time. Group A₁, is remained as control, in this group no hormonal therapy is given.

Craniocaudal and mediolateral radiographs of the fracture site are taken immediately after surgery and subsequent on days 15, 30, 45 and 60 postoperatively. The radiographs are observed for status of fracture reduction and fixation immediately after surgery and subsequently for the maintenance of reduction, progress of fracture healing and complication, if any, at different intervals.

SOIL WATER

Soil water and oxygen share the pore space in soil and generally the oxygen content is determined by the water content, which is added by irrigation or rains and then keeps on changing due to evapotranspiration. Water is the vehicle by which most nutrients move from the soil to root surface. But for the lowland rice, nutrients are most available to plants at ?eld capacity moisture (about 0.3 atmosphere soil water tension) and the availability decreases as the moisture content decreases to wilting point (about 15 atmosphere tension). That is why rainwater or irrigation increases nutrient availability, while extremely dry condition decreases it. There is thus a signi?cant interaction between water and nutrient availability in soil (Singh et al., 2014). In a study in India (Singh et al., 1980) the yield of wheat was signi?cantly affected by irrigation water and nitrogen treatments; maximum yield was obtained with irrigation at 50% available soil water in 60 cm soil depth and 120 kg ha ^–1 nitrogen addition. A study on wheat at Delhi (Kumar et al., 2015) very well shows the effect of irrigation water on yield and uptake of nutrients (NPK) (Table 5.1).

There are nine essential micronutrients, namely, iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), boron (B), molybdenum (Mo), chlorine (Cl), vanadium (V) and nickel (Ni). Out of these, Fe, Mn, Zn, Cu and Ni (Dominic et al., 1978) are taken up by plants in their ionic form X²⁺, Mo as MoO^2-, chlorine as Cl^– form and boron as boric acid (H₃BO₃) or as its ionic form B (OH)₄ ^–. The absorption of vanadium by plants has received only limited attention (Lepp et al., 1983); it may be absorbed as cation V or vanadyl (VO²⁺) and anion vanadate (VO₄ ^3–). Bulk of the information is available on Fe, Mn, Zn and Cu, because of the acceptability of the single DTPA (Diethylene triamine pentaacetic acid)–CaCl₂ extraction test of Lindsay and Norvell (1978) for availability of all these four nutrients followed by their estimation on Atomic Absorption Spectrometer (AAS). Available B is estimated by hot 0.15 M CaCl₂ extraction method (Saha and Singh, 1997). Molybdenum data base is poor, because its determination is dif?cult and Mo de?ciency in crops has not been much noticed in India. Chloride is available in plenty in irrigation water and soil in India and has not received much attention in India.

Internationally maize (Zea mays) and citrus (Citrus sp.) are reported to largely suffer from Zn de?ciency, for which these are considered as marker plants. Zinc de?ciency in maize results in pale or whitish top young leaves and the de?ciency is referred to as 'white bud' (Camberato and Maloney, 2012). In citrus, Zn de?ciency results in ‘rosette’ (cluster of stiff leaves at the end of young shoots) formation (Brennan, 1993). Zinc de?ciency in India was ?rst reported in rice by Nene (1966) at the Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, Uttarakhand, and given the name ‘khaira’ disease due to dark-brown-coloured spots resembling kattha (Acacia catechu extract used in paan – the betel leaves) on the leaves of zinc de?cient plants. Soon All India Coordinated Project on Micronutrients was launched by the Indian Council of Agricultural Research (ICAR) with headquarters at the Punjab Agricultural University, Ludhiana, which was later shifted to the Indian Institute of Soil Science, Bhopal, Madhya Pradesh. About half of the cultivated soils in the India are de?cient in available zinc. Zinc de?ciency is most in Maharashtra and Karnataka and rice-growing states of north and northeast (Table 12.1). A good response of cereals to Zn fertilization has been reported (Rattan et al., 2008).

Soil-rejuvenation power of legumes in crop rotations has been known in several parts of the world since ages. It is mentioned in the Indian agriculture of the Chalcolithic period (ca 1000 BC) (Raychaudhuri and Mira, 1993), in Chinese agriculture in the Han dynasty (ca 2nd century) (Hsu, 1980) and in Roman agriculture (White, 1970). Legumes can be ?tted in cropping systems in India in a number of ways, such as, a crop in a cropping system, a catch crop in an intensive cropping system, an intercrop and as a green manure. A brief discussion on these follows.

The introduction of high-yielding varieties of wheat and rice, the development of intensive cereal–cereal rotations (rice–wheat, rice–rice, hybrid maize–wheat), application of high doses of N (above 100 kg N ha^–1 to each crop) without adequate P and K application, increased use of high-analysis fertilizer (urea and diammonium phosphate in place of ammonium sulphate and superphosphate) and ignoring the application of organic manures led to heavy depletion of P, K, S, Zn and other plant nutrients, which led to wide-spread de?ciencies of P, S and Zn in Indian soils. These de?ciencies of nutrients led to focus on integrated nutrient management.

Plant nutrients are important for increased production of food for the ever-increasing world population. Of the plant nutrients, primary nutrients N, P and K are applied to ?elds each season in fairly large amounts. In addition to increasing crop yields, they also impact the environment. This is briefly discussed in this chapter; only main points are made here.

NITROGEN

Nitrogen is blamed the most for environmental degradation. It contributes to eutrophication of inland and sea-waters, enrichment of air with NH₃ and N₂O and even with global warming. However, it is almost impossible to grow more food without additional nitrogen. It is estimated that by 2050 about 250 million tonnes (MT) of fertilizer nitrogen may be needed to meet global increased food demands as against an estimated current consumption of 116 MT

Cohn (1875) first observed and described a branching filamentous microorganism in the ‘concretions’ (coagulated mass) taken from a lacrimal canal, later identified as Actinomyces israelii. Bollinger first reported the yellow granules in jaw tissues of the cattle in 1877 and established the significance of the bacteria as the etiological agent. In 1878, Israel described the first human case. In 1879, Hartz observed the microscopic appearance of granules of Actinomyces and suggested the name Actinomyces bovis. Mosselman & Lihnaux (1890) and Wolf & Israel (1891) first isolated the bacteria in artificial laboratory media from lumpy jaw cases of cattle and human actinomycosis, respectively.

Streptomyces are soil-borne bacteria known for production of several antibiotics, antifungals, antivirals, antitumoral, anti-hypertensives and immunosuppressives. Krainsky (1914) first described S. griseus and named the species Actinomyces griseus. Waksman and Henrici (1948) changed the name to Streptomyces griseus.

Dermatophilus congolensis was first described from clinical case of exudative dermatitis in cattle in Congo by Van Saceghem (1915). It is primarily known as an animal pathogen causing acute, sub acute or chronic skin disease. The first cases of human infection with D. congolensis were reported in 1961 in four people who developed skin infection after handling an infected deer in USA.

Properties

1. Bacteroides, Dichelobacter and Fusobacterium are major gram negative anaerobes isolated from human and animals. Other gram negative anaerobes are listed below (Table-1).

2. The bacteria are tolerant to oxygen in comparison to strict anaerobes. The bacteria do not die after oxygen exposure.

3. The bacteria naturally inhabit the intestine and mucosal surfaces of human and animals. Majority of them are opportunistic pathogens. Often they cause mixed bacterial infection along with aerobes. The aerobes remove oxygen and create an anaerobic condition favourable for their growth. The aerobes may also supply other growth requirements. For e.g. Porphyromonas asaccharolytica requires vitamin K for its growth, supplied by another aerobic bacterium, not the host.

The word ‘chlamydia’ comes from the Greek word ‘chlamys’ means ‘cloak draped around the shoulder’. It describes how the intracytoplasmic inclusions produced by the bacterium appear under the microscope(‘draped’ around the host cell nucleus). Chlamydia was first discovered by a Czech zoologist and parasitologist, Stanislaus von Prowazek in 1907 in Berlin. Originally because of its structure it was thought to be a virus. In 1963 it was recognized as a bacterium rather than a virus.

Properties of genus

1. Morphology: Chlamydia are Gram-negative, non-motile, pleomorphic and obligate intracellular bacteria. The Gram-negative cell wall consists of cytoplasmic and outer membrane. However, they lack peptidoglycan layer. Moreover, they also encode major outer membrane protein (MOMP), the key antigenic determinant used for serological differentiation of chlamydiae.

They are poorly stained by Gram’s stain. Chlamydiae are readily stained by Castaneda (blue in appearance), Giemnez and Macchiavello (red in appearance) methods. However, Giemsa staining is preferable to stain the inclusions (chlamydial micro colony) in the cell culture. Inclusion bodies of the Chlamydiae are basophilic in nature. The staining of the inclusion bodies may differ depending on the species. In C. trachomatis, the inclusion bodies contain glycogen matrix and can be easily stained with iodine solution.

World Scenario

The world climatic conditions are divided into Tropical; Sub-Tropical and Temperate climates. Fruits and Vegetables suited to these climatic conditions are grown successfully. Considering the nutritional and economic importance of fruits and vegetables, there is tremendous increase in area and production of fruits and vegetables throughout the world. The present global scenario of fruit and vegetable crops (areas harvested, production and productivity (yield) has been given in Table 1. It shows that the fruits 865.88 million tones has been harvested from 65.24 million Ha land with productivity 13.27 t/ha (Table 1) where as vegetables produced 1075.20 million tonnes from area 57.00 million ha with yield 18.86 tonnes/ha (Table 1) during 2016.

Fermentation

The decomposition of carbohydrates by microorganisms and enzymes is known as fermentation. During fermentation process of food organic acids and alcohol etc are produced which act as preservatives and also provide fine flavor and aroma that increase the value of raw materials. Most fermented foods contain a complex mixture of carbohydrates, proteins and fats etc. Fermentation occurs when microorganisms consume susceptible organic substances as a part of their own metabolic processes. Natural fermentation is probably oldest form of food preservation.

History in general reveals chronological account of important events, contribution of persons who significantly influenced the thinking of their era and the interpretations of the observed facts or phenomenon over the period of time. The progress in plant pathology leading to the major land mark in mycology, plant bacteriology and plant virology will be discussed in chronological order for easy and better understanding.

a) Definition

Fungus is Latin word meaning ‘mushroom’

Alexopoulus and Mims 1979 defined fungus as eukaryotic, achlorophyllous organism generally produced by sexual or asexual method and whose filamentous branched somatic structure is typically covered by cell wall.

Bacteria

Definition

Bacteria belong to prokaryota which encompasses organisms with a primitive type of nucleus lacking a clearly defined membrane. The bacteria are smaller than fungi and measure about 0.5 to 1.0 x 2.0 to 5.0µ.