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Several environmental conditions affect the density and composition of the microflora and frequently alter their activities in soil. Primary factors include soil moisture, aeration, temperature, pH, organic matter and inorganic fertilizers. Lesser variables are the secondary factors, which include crop rotation, season, soil depth, cultivation practices etc.

I. Primary Factors

Soil moisture

Soil moisture is one of the important factors influencing the microbial population. Water is the major component of protoplasm; an adequate supply must be available for vegetative development of organisms. But, when it becomes excessive, proliferation is suppressed due to limitation in gaseous exchange and lowers the availability of O₂ supply creating an anaerobic environment. Most of the organisms prefer a moisture percentage between 20 and 60 per cent. Many bacteria and fungi can adjust themselves to different moisture conditions. Under dry conditions, the bacteria may form spores that can resist the drought conditions. The fungi may sporulate or form chlamydospores to tide over adverse conditions. The protozoans also may form cysts and can survive under dry conditions. Actinobacteria are the chief group of organisms that prefer dry conditions. It is believed that the concentration of nutrients is diluted and also the aeration is very much limited at moisture and hence only the anaerobic and microaerophilic organisms can develop better.

Soil microorganisms (Flora & Fauna) are just like higher plants depends entirely on soil for their nutrition, growth and activity. The major soil factors which influence the microbial population, distribution and their activity in the soil

Soil microbial biomass is an important parameter linking the plants to soil. It comprises about 2-3% of the total organic carbon in the soil and recognized as an important source of nutrients to plants. It is also a dynamic component of the soil associated with several functional properties of the terrestrial ecosystem. It represents the fraction of the soil responsible for the energy and nutrient cycling and the regulation of organic matter transformation.

Microbial biomass is a small but labile and living component of soil organic matter that is involved in most bio-geo-chemical processes in the terrestrial ecosystem. It interacts with crop productivity by regulating nutrient availability as a source; determining soil carbon storage- sink; and contributing to the atmospheric CO₂ from respiration. Thus it is the main agent that controls the flow of carbon and cycling of nutrient elements.

There is a close relationship between soil microbial biomass, decomposition rate, and nitrogen mineralization. It is also positively correlated with grain yield in organic farming and also contributes to soil structure and stabilization. Thus, there is the immense importance of microbial biomass in soil fertility as well as in agriculture.

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.

All organisms require the six elements CHNOPS in sizable quantities, and that these minerals may occur in different forms. Depending on whether the local environment is aerobic or anaerobic, the exact chemical form of any of these elements may change quickly and drastically. Example: : If the soil becomes waterlogged and anaerobic, sulfate will be converted into hydrogen sulfide and nitrate into nitrogen gas or ammonia (via anaerobic respiration). As the water recedes and the soil becomes aerobic again, the ammonia is oxidized back to nitrate in stages. All of this (and many other processes) occur largely because of the activities of soil microbes. Without these microbes, life as we know it would not occur because necessary elements would remain tied up in unusable chemical forms and gradually be removed by sedimentation. To maintain the level of these components it is essential that they undergo a regular process of recycling. Different microorganisms bring about this process of recycling through various transformations.

Carbon Cycle

The most important element in the biological realm and substance that serve as the cornerstone of the cell structure is carbon. It constituents about 40-50% of all living organisms, yet the ultimate source is the CO₂ that exists in a perennially short supply, only 0.03% of the earth’s atmosphere, which undergoes a cyclic change from an oxidized to reduced state. The concentration of carbon in living matter (18%) is almost 100 times greater than its concentration in the earth (0.19%). Hence, living things extract carbon from their non-living environment. For life to continue, this carbon must be recycled. Carbon exists in the nonliving environment as carbon dioxide (CO₂) in the atmosphere and dissolved in water (forming HCO₃") carbonate rocks (limestone and coral = CaCO₃) deposits of coal, petroleum, and natural gas derived from once-living things dead organic matter, e.g., humus in the soil. Carbon enters the biotic world through the action of autotrophs: primarily photoautotrophs, like plants and algae, that use the energy of light to convert carbon dioxide to organic matter through photosynthesis and to a small extent, chemoautotrophs - bacteria and Archaeans that do the same but use the energy derived from the oxidation of molecules in their substrate.

Soil Organic Matter

Soil organic matter plays an important role in the maintenance and improvement of soil properties. It is a dynamic material and is one of the major sources of nutrient elements for plants. Soil organic matter is derived to a large extent from residues and remains of the plants together with the small quantities of animal remains excreta, and microbial tissues. Soil organic matter is composed of three major components i.e. plant residues, animal remains and dead remains of microorganisms. Soil organic matter comprises residues of plants and animals and these compounds occur in soil in close combination with inorganic substances. Animals and plant residues are made up of complex carbohydrates, simple sugars, starch, cellulose, hemicellulose, pectins, gums, mucilage, proteins fats, oils, waxes, resins, alcohols, aldehydes, ketones, organic acids, lignin, phenols, tannins, hydrocarbons, alkaloids, pigments, etc.

The organic matter subjected to microbial decay in the soil comes from several sources like plant remains, forest litter, incorporation of plant tissues, animal tissues, and excretory products. The chemistry of organic matter is very complex, and investigations of the transformations and the responsible organisms have therefore been extremely interesting. The organic constituents of the plants are commonly divided into six categories.

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.

Fixation of elemental nitrogen in the atmosphere by the microorganisms through a reductive process into ammonia is called biological nitrogen fixation (BNF). Molecular nitrogen (N₂) is the major component (approximately 80%) of the earth’s atmosphere. The element nitrogen is an essential part of many of the chemical compounds, such as proteins and nucleic acids, which are the basis of all life forms. However, N₂ cannot be used directly by biological systems to build the chemicals required for growth and reproduction. Before its incorporation into a living system, N₂ must first be combined with the element hydrogen. This process of reduction of N₂ commonly referred to as nitrogen fixation (N-fixation).

N₂is transformed into reactive N via lightning discharge (5 teragrams (Tg) N / year; 1 Tg equals 1012 g) and by biological N fixation (100 -140 Tg N /year ). Conversion of dinitrogen to ammonia in the industrial process requires temperatures of 400 - 500^o C and high pressures (Haber-Bosch process). Biological nitrogen fixation is much more important as it contributes to more than 70 % of the input in to the world’s soil and water nitrogen. It has been estimated that 100 to 175 million tones of nitrogen are fixed annually by the process of biological nitrogen fixation.

The process of N₂ fixation is mediated by the enzyme, called nitrogenase (which reduces N₂ to ammonia). The overall reaction is as follows.

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.

Potassium (K) is among the most important essential macronutrients for plant growth. About 98% of the potassium in the earth’s crust exists in insoluble forms as rocks and silicate minerals, resulting in very low concentrations of soluble potassium in the soil for plant growth and development. Potassium is never incorporated in any organic compound and even in the plant system it remains as K⁺ ion. It does not form any gas that could be lost to the atmosphere. It does not cause eutrophication. When left in the ecosystem as such, it is not at all toxic.Potassium activates enzymes, maintains cell turgor, enhances photosynthesis, reduces respiration, helps in transport of sugars and starches, and is essential for protein synthesis. In addition to plant metabolism, potassium improves crop quality because it helps in grain filling and kernel weight, strengthens straw, increases disease resistance and helps the plant better to withstand stress.

Potassium in Soils

Soils usually contain potassium in larger amounts than any other nutrients. Total K content in soil is 30,000- 50,000 kg/ha in top layer of the soil. Nearly 98 % of K bound in the mineral form and 2 % is in soil solution. Generally, potassium in soils exist in four forms (often called fractions), their availability to crop roots is considerably different.

Zinc is found in earth’s crust to the tune of 0.008%. However about 50% of Indian soils exhibit deficiency of zinc with a content much below the critical level of 1.5 ppm. Soil contains both available and unavailable form of zinc. Water soluble, exchangeable, organically complexed and armorphous iron oxide bound forms are considered available zinc and crystalline iron oxide bound and residual zinc are considered as unavailable. The available fraction constitutes around 8% of the total zinc which is too low for utilization by crops in zinc deficient soils.

Zinc is required by crops in microquantities for its growth. The use of high analysis fertilizer due to cultivation of high yielding varieties, enhanced cropping intensity and the decline in the use of organic manures result in the deficiency of trace elements particularly zinc. With the liberal application of nitrogen the demand for zinc increases producing deficiency symptoms. The critical limit of zinc in dry matter for different crops and levels less than 20 ppm suggests the probability of zinc deficiency and less than 15 ppm indicate sure deficiency.

Zinc is a limiting factor in crop production and application of ZnSO₄ is preferred because of its water soluble nature. The zinc sulphate, when applied soil, gets transformed into different forms like Zn (OH), zinc carbonate in calcium rich alkali soils ; zinc phosphate in near neutral to alkali soils of high phosphorus application; and zinc sulphide under reduced conditions.

Bioconversion refers to the recycling and reprocessing of organic waste materials using the system of biological decomposition or biodegradation into value added products. Composting is one way of conversion of organic waste into manures. It is defined as a method of solid waste management whereby the organic component of the solid waste stream is biologically decomposed under controlled conditions to a state in which it can be handled, stored or applied to the land without adversely affecting the environment.

Composting provides a partial solution to an issue of great concern in many communities. All around the world, landfills are filling up, garbage incineration is becoming increasingly unpopular, and other waste disposal options are becoming ever harder to find. Composting provides a way not only of reducing the amount of waste that needs to be disposed of, but also of converting it into a product that is useful for agriculture. Composting reduces waste, makes us less dependent on landfills, and decreases greenhouse gas emissions. Composting recycles essential nutrients back into the soil and promotes a prolific soil ecosystem.

Pesticides are the chemical substances that kill pests and herbicides are the chemicals that kill weeds. In the context of soil, pests are fungi, bacteria, insects, worms, and nematodes etc. that cause damage to field crops. Thus, in broad sense pesticides are insecticides, fungicides, bactericides, herbicides and nematicides that are used to control or inhibit plant diseases and insect pests. Although wide-scale application of pesticides and herbicides is an essential part of augmenting crop yields; excessive use of these chemicals leads to the microbial imbalance, environmental pollution and health hazards. An ideal pesticide should have the ability to destroy target pest quickly and should be able to degrade nontoxic substances as quickly as possible.

The ultimate “sink” of the pesticides applied in agriculture is soil. Soil being the storehouse of multitudes of microbes, in quantity and quality, receives the chemicals in various forms and acts as a scavenger of harmful substances. The efficiency and the competence to handle the chemicals vary with the soil and its physical, chemical and biological characteristics.

Rhizosphere

The term Rhizosphere was introduced by the German scientist, Hiltner in 1904. It is region of the soil, which is subjected to the influence of plant roots. It is the unique environment under the influence of plant roots. The roots of plants are not only involved in the uptake of mineral nutrients and water for plant growth, but they also release a wide range of organic compounds in the surrounding soil.

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.

Microbes that live inside plant tissues without causing disease are termed as endophytes. Endophytes have been found in all parts of plant viz., seeds, roots, stems, leaves, fruits etc. Within these organs, there is evidence of endophytes living in apoplastic intercellular space within parenchyma tissues and xylem vessel apoplast. Endophytic bacteria have been isolated from both monocotyledonous and dicotyledonous plants, ranging from woody tree species to herbaceous crop plants. Further, a single plant may be a host for several different bacterial species. They are consistently present in the root, stem, leaf, fruit and tuber tissues of a wide range of agricultural, horticultural and forest species. All plants in nature harbor a diverse community of endophytic bacteria which can positively affect host plant growth.

The potential of endophytic bacteria to fix nitrogen, promote plant growth and suppress plant diseases has renewed interest in such associations. It is advantageous to have the endophytic plant growth promoting organisms safely inside the plant, which could supply substantial amounts of nitrogen and other nutrients, growth hormones and other beneficial effects to the crop plants without the interference of the rhizosphere soil environment. Furthermore, plant growth promotion is often greater when it is induced by endophytes rather than by rhizosphere bacteria.

Plant Growth Promoting Rhizobacteria (PGPR) are root-colonizing bacteria that form symbiotic relationships with many plants. The name comes from the Greek rhiza, meaning root. Though parasitic varieties of rhizobacteria exist, the term usually refers to bacteria that form a relationship beneficial for both parties (mutualism). They are an important group of microorganisms used in biofertilizer. Biofertilization accounts for about 65% of the nitrogen supply to crops worldwide. The term PGPRs was first used by W. Kloepper in the late 1970s and has become commonly used in scientific literatures. PGPRs have different relationships with different species of host plants. The two major classes of relationships are rhizospheric and endophytic. Rhizospheric relationships consist of the PGPRs that colonize the surface of the root, or superficial intercellular spaces of the host plant, often forming root nodules. Endophytic relationships involve the PGPRs residing and growing within the host plant in the apoplastic space.Some common examples of PGPR genera exhibiting plant growth promoting activity are: Pseudomonas, Azospirillum, Azotobacter, Bacillus, Burkholdaria, Enterobacter, Rhizobium, Erwinia, Mycobacterium, Mesorhizobium, Flavobacterium, etc.An ideal PGPR should possess high rhizosphere competence, enhance plant growth capabilities, have a broad spectrum of action, be safe for the environment, be compatible with other rhizobacteria, and be tolerant to heat, UV radiation, and oxidizing agent.

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.

Industrial microbiology is an important area of applied microbiology. In a broader sense, industrial microbiology is concerned with all aspects of business that relate to microbiology. It refers to the use of microorganisms in commercial enterprise. Cheap raw materials are converted to valuable products through the metabolism of microbes. Microbes for this purpose could be exploited in different ways.

Various commercial products of economic value made by microbes are :

Silage is preserved pasture. Fresh forage crops such as maize, grasses, legumes, wheat and lucerne can be preserved by ensiling. Silage is the green material produced by controlled fermentation of the green fodder crop retaining the high moisture content, which contain 20-40% dry matter.

Silage can be prepared from plants having thick stems and are generally not very suitable for hay making like sorghum, maize. Weeds can also be utilized along with main fodder crops for silage making. Silage making kills majority of weed seeds. It is highly palatable. The organic acids produced in the silage are similar to those normally produced in the digestive tract of the ruminants and therefore are used in the same manner.

Introduction

Biofertilizers are microbial preparations containing living or latent cells of efficient strains of nitrogen fixing, phosphate solubilizing and cellulose decomposing microorganisms intended for seed or soil application and designed to improve soil fertility and plant growth by increasing the number and biological activity of beneficial microorganisms in the soil.

The objects behind the application of biofertilizers /microbial inoculants to seed, soil is to increase the number and biological / metabolic activity of useful microorganisms that accelerate certain microbial processes to augment the extent of availability of nutrients in the available forms which can be easily assimilated by plants. The need for the use of biofertilizers has arisen primarily due to two reasons i.e. though chemical fertilizers increase soil fertility, crop productivity and production, but increased / intensive use of chemical fertilizers has caused serious concern of soil texture, soil fertility and other environmental problems.Use of biofertilizers is both economical as well as environment friendly. Therefore, an integrated approach of applying both chemical fertilizers and biofertilizers is the best way of integrated nutrient supply in agriculture.

Biofertilizers, thus include i) Symbiotic nitrogen fixers- Rhizobium sp. ii) Non-symbiotic, free living nitrogen fixers- Azotobacter, Azospirillum etc. iii) Blue Green Algae (BGA) inoculants- Azolla-Anabaena, iv) Phosphate solubilizing microorganisms (PSM)- Bacillus, Pseudomonas, Penicillium, Aspergillus etc. v) Mycorrhiza vi) Cellulolytic microorganisms

Mycorrhizal symbiosis is the most prevalent and important mutualistic association in plant kingdom. ‘Mycorrhiza’- the word means fungus - root, this association was reported by A.B.Frank in the year 1885. Nearly 95% of plant species form this mycorrhizal association. This serves as critical linkage between plant roots and soil and characterized by the movement of plant produced carbon to fungus and fungal acquired nutrients to plants. Through its hyphae this fungus absorbs the available P from soil and transports directly to root cortex. Mycorrhizal associations vary widely in structure and function. There are seven types of mycorrhizae (Table 1). These are endo (arbuscular), ecto, ectendo, arbutoid, monotropoid, ericoid, and orchidaceous mycorrhizae. Among them, endomycorrhizae and ectomycorrhizae are the most abundant and widespread

For many soil borne diseases, effective and economic control methods are not available. Several soil borne pathogens have developed resistance to many fungicides. The beneficial microbes are also affected by fungicides. Many fungicides pose health hazards by polluting food and water and cause direct toxicity of heavy metals and carcinogenic risk. In the context of growing worldwide awareness of environmental pollution and development of fungicide resistant strains of pathogens, biological method of suppression of disease causing organisms have been recognized as the safest approach for plant disease management.

Biological control of plant diseases is the suppression of populations of plant pathogens by living organisms. Amongst beneficial microorganisms, isolates can be selected which are highly effective against pathogens and can be multiplied on artificial media. Application of such selected and mass produced antagonists in high densities once or several times during a growing season is called “augmentative biological control”.

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).

Mass Production of Bacterial Inoculants

Strain Selection and Improvement

In biofertilizer technology, strain selection occupies the foremost criteria, so as to explore its biological potentialities for the beneficiary crop. The selected strain used in biofertilizer production must be efficient to grow fast besides retain desirable potentialities of biological activities, which should be present in desired high numbers and must be stable. The strain must be improved periodically so as to sustain the productivity.

Biofertilizers are one of the important components of organic farming and sustainable agriculture. Awareness among farmers is increasing on the biological fertilizers. But, the success of biofertilizer inoculation depends on the quality of the inoculant used. Because farmers are unable to judge the quality of the inoculants at the time of purchase or even at use. The inoculant producers are negligent to institute quality control programmes. Unfortunately much of the inoculant produced in the world today is relatively of poor quality. In such situation maintaining high quality inoculant products depend on the internal implementation of effective quality control systems by manufacturer. A major goal of a quality standard is to control the quality of inoculant to be used in any country.

Bacterial biofertilizers are supplied as carrier based inoculants. Peat or lignite is used as carrier material. Carrier based bacterial inoculants are applied by the following methods.

1. Seed treatment or seed inoculation.
2. Seedling root dip and
3. Main field application

Seed Treatment

One packet of the inoculant (200 g) 7is mixed with 200 ml of rice kanji to make a slurry. The seeds required for an acre are mixed in the slurry so as to have a uniform coating of the inoculant over the seeds and then shade dried for 30 minutes. The shade dried seeds should be sown within 24 hours. One packet of the inoculant (200 g) is sufficient to treat 10 kg of seeds.

At this moment, the majority of energy is obtained from fossil fuels and requires switching over to alternative energy sources is the need of the hour. Fossil fuels are nonrenewable energy source and also have seriously negative impacts on the environment. The use of fossil fuels cause excessive global climate change because emissions of greenhouse pollutants and the formation of compounds CO_x, NO_x, SO_x, C_xH_y, ash and other organic compounds that are released into the atmosphere. The increase in greenhouse gas emission will result in global warming, climate change, environmental degradation and health problems.

Biofuel, any fuel that is derived from biomass - that is, plant or algae material or animal waste. Since such feedstock material can be replenished readily, biofuel is considered to be a source of renewable energy, unlike fossil fuels such as petroleum, coal, and natural gas.

The communication module is a device which is used to control the communication between the stations. This chapter explores the different communication modules and their specifications.

5.1 WiFi

ESP8266 WiFi Module is a WiFi serial transceiver module. This chip has a full TCP/IP protocol stack with the computational power onboard. This makes the board simple to use as Wi-Fi connection board. The specification of this board includes, 32-pin QFN package, Integrated RF switch, Integrated RISC processor. It has on-chip memory with external memory interfaces, integrated MAC/baseband processors, Quality of Service management, on chip regulator, Integrated WEP, TKIP, AES, and WAPI engines, 11 b/g/n. It has integrated TCP/IP protocol stack and Integrated PLLs, regulators, DCXO and power management units. It has +19.5dBm output power in 802.11b mode and Power down leakage current of <10uA

5.2 Bluetooth

Bluetooth is a wireless protocol. The recent introduction of Bluetooth with Low Energy extension is also as iBeacon. The advantage of BLE4.0 standard includes the low power consumption, which makes it a better option to be used in smart phones. This facilitates the setup of a mesh network of Bluetooth devices, with lower latency and higher range respect to standard Bluetooth.

This is a SMD BLE module based on TI cc2541 chip. It has low cost, small and easy to use. The preloaded firmware allows to build BLE communications with AT command. It supports communication with iPhone, iPad (iOS 5.0 or greater) and Android 4.3 or greater. It works on frequency: 2.4 GHz ISM band and modulation method is GFSK (Gaussian Frequency Shift Keying). It has transmission power: - DBM, 23-6 DBM, 0 DBM, 6 DBM, can be modified by the AT command. It works on baud rate 9600bps. It can operate on temperature range -40 ~ 125°C.

Another interesting board is the HC-05 Bluetooth module. Specifications of the works Master/Slave configurations. It operates on frequency of 2.4GHz ISM band with Modulation GFSK(Gaussian Frequency Shift Keying).

Robots can replace human efforts in the future. Discovery of robots in agriculture is going to accelerate the growth of agriculture 4.0. Nursery planting needs robust and profitable solutions. Nursery plants deals with the direct consumer, which is the primary stage of agriculture. An intensive care is required to look after the nursery plant before going to be planted. Now a days robots are used to monitor the plants, essentially to maintain the health standard of a plant. This chapter illustrate the applications of the robots in nursery planting.

6.1 Introduction

Nursery is the primary stage where seeds are grown in to the young plants. Nursery planting involves many activities like seeding, potting and monitoring. The process required high attention to look after at this stage [1]. As the food demand is increasing day by day, it is necessary to adapt unconventional way of farming. Bringing robots in to the farming will bring a lot of changes in the traditional agriculture. The robotics in agriculture is not new, it has started with evolution of autonomous vehicles [2]. The usage of robots are increasing exponentially. So the researcher and scientist also started use of robots in agriculture. They found a phenomenal result in term of easy to handle the agro tasks, seeding, weeding, automatic irrigation and harvesting. It draws the farmer attention down the line [3].

Agriculture is the backbone of India. Evolution in technology is bringing new dimensions of conventional agriculture. Looking towards the current food demands it is very crucial to maintain the food supply. According to UN (United Nations), by 2050 the world population will be increased to around 9.3 billion which increases the food need. As the technology in agriculture evolving it seems that we could be able transform conventional farming to unconventional and traditional to modernization by the help of agriculture robots. Agri-bots can be autonomous with human intervention that could perform the task precisely. Chapter illustrates the applications in agriculture seeding. These robots are efficiently used in crop seeding.

7.1 Introduction

The very first agriculture robots were used in the early 1920s along with autonomous vehicle development.

Agro robots are becoming an ongoing pattern in farming with lots of research advancement and business models [1]. Agrarian robots have huge focal points as far as adaptability, flexibility and ecological advantages contrasted with customary horticultural apparatus and speak to an extraordinary resource for cutting edge precision agribusiness. Numerous advances in machine vision with imaging and otherworldly cam-periods for distinguishing weeds, vermin and infections, supplement inadequacies in soil or plant leaves have given profound applications to be mounted on independent vehicles for exploring soil and crops and for additional downstream choice help and control [2]. The mechanical network has additionally made earth shattering upgrades and advancements as far as utilizing a far reaching working framework, the Robotic Operating System (ROS), just as applying strong stages and route calculations.

Comparable to horticultural robots, the attributes of the central framework of robots are the lightweight, little size and lively self-governance [3]. Lightweight implies that the vehicle requires lower impetus vitality and incites less soil compaction while simultaneously the vehicle must be little for security reasons, for accomplishing more noteworthy accuracy during execution of assignments and having more maneuverability inside the field to limit turning delays.

Precision Agriculture is fulfilled by adapting suitable monitoring and analysis mechanisms. Autonomous monitoring is getting a new dimension using robots. Agriculture is the trending area to attract new professionals, investors and new companies. The technology in agriculture is not only increasing the yields but the time and labour. This chapter illustrates the use of robotics in crop monitoring and analysis.

8.1 Introduction

Monitoring of agriculture farm enhance the productivity. Evolution in technologies in the era of agriculture brought a lot of innovations. Among these innovations robots are one of them to be implemented in agriculture to enhance profitability and reliability with minimum human resource. At the same robots were deployed to monitor the farming land from weeds and try to remove these. Due to which uses of agrochemicals reduced down the time line. When precision farming came in to the pictures robots are the best use cases. In fig. 8.1 autonomous mechanical robots are shown, which are used to remove the weed from farming land. Robots are equipped with sensor modules, actuators and IoT enabled which makes the things very easy to control from remote area with commands.

Agriculture irrigation is a crucial part of precision farming. An irrigation system required a lot concentration to grow the plant healthy. A smart irrigation system in an agriculture farm leads to maximum profits in terms of yield. Integrating technologies like IoT (Internet of Things), AI (Artificial Intelligence) in irrigation accomplish to the human efforts. Controlling of water pumps, sprinklers seamlessly draws the kind attention of farmer to adapt these technologies in their day today farming schedules. This chapter illustrates a wide variety of robots used in irrigation to achieve maximum yield and minimizing water loss. The high scalability and reliabilities of these autonomous robots replicates the potential of agriculture 4.0 in coming future. Advanced robots deployed on the field to monitor the land and pass the information to the controllers and further to the water pumps. Here case study of robots is highlighted to reduce water losses by using nozzles mechanisms.

9.1 Introduction

Agriculture faces many environmental challenges. As far as the irrigation in agriculture is concerned it is very essential to maintain soil hydrated and water level in the field. Robotic irrigation enables autonomous irrigation from remote access [3]. Smart irrigation technique enables a lot of water saving. So robotic in agriculture plays a very crucial role in it [2]. In order to avoid water losses agro robots adapt smart irrigation techniques like droplet irrigation and sprinkling. To maintain sustainability, water resource management is required. Technologies like drones, smart sprinkler based on IoT, smart droplet irrigation used across the globe. These technologies have the greatest impact on productivity and sustainability of the environment as well. As far as the country India is concerned, due to diversity in geographical infrastructures rainfall changes from state to states. So, a wide range of water diversity is found to grow agricultural foods. For example northeast and southern part of India due to heavy rainfall paddy cultivation is preferred since it requires a lot of water. Whereas the northern part of India observe a moderate rainfall, so vegetables and other agriculture foods get cultivated. At the same there are certain states like Rajsthan, Gujrat where very less rainfall occurs through varieties of crops related to dal.

Weed control in agriculture disturbs the farming. Weed management and control essentially increase productivity of the farm. Autonomous robots for weed control systems are gaining a lot of attention. Adaptability of effective weed control robots has the potential to bring evolution in the areas of weed species, genetics and climate conditions. Weed control is one of the major challenges in agriculture. Removal of weeds from farming land required a lot of human effort. To minimize the weed growth pesticides and chemicals are used which is very harmful. In order to make this process easy and reliable robots are used nowadays. Robots are specially designed to detect the weeds and remove them within a stipulated time period. Robots are programmed using various algorithms to do this task in an efficient way without human efforts. This chapter illustrates the use of modern robots in weed control to help the farmers to gain maximum profit and healthy concerns without using chemicals to do so.

10.1 Introduction

Over the time, weed control in a farming land has been an issue. Evolution in technologies in the area of agriculture brought a lot of innovations. Among these robots are one of the innovations to be implemented in agriculture to enhance profitability and reliability with minimum human resource. The robots are deployed to monitor the farming land from weeds and try to remove these. Due to which uses of agrochemicals reduced down the timeline. When precision farming came into the picture robots are the best use cases. An autonomous mechanical robot was used to remove the weed from farming land. Robots are equipped with sensor modules, actuators and IoT enabled which makes the things very easy to control from remote area with commands [4].

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

11.1 Introduction

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

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

11.1 Introduction

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

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

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

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

12.1 Introduction

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

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

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

13.1 Introduction

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

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

14.1 Introduction

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

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

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

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

15.1 Introduction

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

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

Nutritive Value

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

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

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

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

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

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

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

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

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

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

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

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

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

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