eChapters

Saline Water Agriculture has been drawing interest as one of the solutions for limitation of world fresh water supply, farmland availability, salinity ingression and the pressing future need of food supply. The cultivation of salt-tolerant crops on saline soil and with saline waters has significant social and economic potential.

It is often argued that fresh water agriculture near rivers and ponds was invented because of the need to sustain people and communities. Saline water agriculture is going to be needed for sustaining our future generations and civilization.

for limitation of world fresh water supply, farmland availability, salinity ingression and the pressing future need of food supply. The cultivation of salttolerant crops on saline soil and with saline waters has significant social and economic potential. It is often argued that fresh water agriculture near rivers and ponds was invented because of the need to sustain people and communities. Saline water agriculture is going to be needed for sustaining our future generations and civilization.
FROM DESALINATION OF SEA WATER TO SEA WATER AGRICULTURE
Sea water contains nearly 35000 ppm of dissolved salts. There has been great deal of interest world wide on desalination of sea and brackish water to safe drinking water. In early 1960s the young President of USA John Kennedy put forward two famous challenges for the scientists (1) Landing the man on moon and (2) Producing desalinated water at low and competitive cost. It is often said that the first challenge was met but the second one has been more difficult! With tremendous support and interest, work on desalination was taken up worldwide. Newer processes were being tried. At the Environmental Research Lab of University of Arizona and at Central Salt and Marine Chemicals Research Institute, Bhavnagar simultaneously solar powered HD (humidification – dehumidification) process of Desalination was developed and pilot plants were commissioned. It was however realized that desalinated water was costly and not easily applicable to most coastal communities, though for many countries in middle east with no alternative water source and cheap petroleum energy – it is applicable on a very large scale.

There are four major tracts where salt affected soils are commonly met within India. These are:

1. The Semi-arid Indo-Gangetic alluvial tracts (mainly in Punjab, Haryana, Uttar Pradesh and a part of Bihar)
2. The arid tracts of Rajasthan and Gujarat.
3. The arid and semi arid tracts of southern states, particularly of the irrigated rigor (Vertisols) soils.
4. The coastal alluvium

Earlier it was estimated that about 7 million hectares of land have been affected by salinity/sodicity conditions in India. The area under these soils increased and reached to the level 10 million hectares at present.

11.1 Introduction

Salinity is the saltiness or dissolved salt content of a body of water. The technical term for saltiness in the ocean is halinity, from the fact that halides, chloride specifically are the most abundant anions in the mix of dissolved elements. In oceanography, it has been traditional to express halinity not as percent, but as parts per thousand (ppt ), which is approximately grams of salt per liter of solution. In other disciplines chemical analyses of solutions, and thus salinity is frequently reported in mg/L or ppm (parts per million). Prior to 1978, salinity or halinity was expressed as % usually based on the electrical conductivity ratio of the sample to “Copenhagen water”, an artificial sea water manufactured to serve as a world “standard”(Lewis, E.L 1980). In 1978, oceanographers redefined salinity in Practical Salinity Units (psu): the conductivity ratio of a sea water sample to a standard KCl solution (UNESCO, 1981a) (UNESCO, 1981b). Ratios have no units, so it is not the case that 35 psu exactly equals 35 grams of salt per litre of solution (UNESCO, 1985).

These seemingly esoteric approaches to measuring and reporting salt concentrations may appear to obscure their practical use; but it must be remembered that salinity is the sum weight of many different elements within a given volume of water. It has always been the case that to get a precise salinity as a concentration and convert this to an amount of substance required knowing much more about the sample and the measurement than just the weight of the solids upon evaporation. For example, volume is influenced by water temperature; and the composition of the salts is not a constant. Saline waters from inland seas can have a composition that differs from that of the ocean. For the latter reason, these waters are termed saline as differentiated from ocean waters, where the term haline applies.

The total amount of salts dissolved in water is known as salinity. Salinity of water is denoted as ppt, g/L, psu. Salinity of different water has been classified as Freshwater 0-0.5 ppt, Brackish water 0.5-30ppt and Marine water > 300 ppt.
Reagents
1. Silver nitrate (AgNO3) (0.1N): Dissolve 4.25 g silver nitrate in distilled water and make the total volume 250 ml by shaking.
2. Potassium chromate (K2CrO4) indicator (5%): Dissolve 2.5 g potassium chromate in distilled water and make the total volume 50 ml by shaking.
Procedure
1. Salinity in estuarine and coastal water can be estimated by this method.
2. Take 10 ml of water sample in a 50 ml conical flask.
3. Add 3-4 drops of potassium nitrate indicator solution to it.
4. Titrate against 0.1N Silver nitrate till the yellow colour changes to brick red.

Abstract

The Saanich (Coast Salish) are an Indigenous people of southern Vancouver Island on the southwest coast of Canada who for many centuries have relied heavily on anadromous Pacific salmon (Oncorhynchus spp.) as a major food source. Over time, Saanich fishers have become experts on many aspects of these salmon, including knowledge of the different species, their life cycles, feeding ecology, migration routes, and population dynamics. Much of this knowledge is centered at Saanich Inlet and Goldstream River, a major salmon spawning stream flowing into this inlet. Some Saanich and other Coast Salish people still fish for salmon at Goldstream using traditional gaff hooks and spears, but they have also adopted more modern gear in recent times. Pacific coho (O. kisutch) and chum (O. keta) salmon stocks in particular have fluctuated over the decades, evidently due to impacts of commercial fishing, pollution from oil leakage and domestic sewage in Saanich Inlet.

Salmonella consists of bacilli leading to Enteric fever, Gastroenteritis, Speticaemia etc. The important member of the genus is Salmonella typhi, which causes Typhoid fever. Salmonella are of two groups;
(i) Enteric fever group consisting of typhoid & Paratyphoid bacilli exclusively or primary human parasites
(ii) Food poisoning group, which are animal parasite but may infect humans causing gastrointestinal infections Salmonella is oxidase negative, catalase positive, indole and Voges Proskauer (VP) negative, methyl red and Simmons citrate positive, H₂S producing andurea negative.
Characteristics
Cells are rod-shaped, non-spore-forming, and predominantly motile by means of peritrichous flagella with diameters of around 0.7-1.5μm and lengths of 2-5μm with a few exceptions. On blood agar, colonies are 2-3mm in diameter. Colonies are generally lactose non-fermenters. They obtain their energy from oxidation and reduction reactions using organic sources, and are facultative anaerobes. They produce acid from glucose usually with the production of gas, and are oxidase negative. Most produce hydrogen sulphide except Salmonella paratyphi A and Salmonella typhi, which is a weak producer. They are identified
with a combination of serological and biochemical tests. Salmonella species are classified and identified into serotypes according to the White-Kauffmann-Le Minor scheme; there are more than 2,500 Salmonella
serotypes that have been described and reported.

Salmonellosis is one of the important zoonoses, acute or chronic in nature, affected by all species of animals, birds and humans and characterized by gastroenteritis.

Etiology: The genus Salmonella belongs to the family Enterobacteriaceae. Currently there are 2463 serotypes (serovars) of Salmonella. According to the current system used by the CDC the genus Salmonella contains two species each of which contains multiple serotypes. The two species are S. enterica, the type species and S. bongori. The S. enterica subsp. enterica is divided into 6 subspecies. S. enterica subsp. enterica I is divided into serotypes, for example serotypes enteriditis, typhimurium, typhi and choleraesuis. The majority of 2463 Salmonella serotypes belong to S. enterica subsp. I and associated mainly with warm blooded vertebrates and are responsible for most Salmonella infections in humans and domesticated animals. Other serovars are restricted in their host range causing severe systemic disease in only one host. For example, S. typhi is restricted to infection in humans, S. abortusovis to infection in sheep, S. dublin in cattle, S. abortusequi in horses and S. choleraesuis in pigs. The serotypes (serovars) that most commonly cause Salmonellosis in farm animal species are as follows:

Cattle: S. typhimurium, S. dublin, S. newport

Sheep and goat: S. abortusovis, S. typhimurium, S. dublin, S. anaturn

Pig: S. typhimurium, S. choleraesuis

Horses: S. typhimurium, S. abortusequi, S. anatum, S. newport, S. enteritidis, S. arizona, S. angona, S. heidelbers

The organisms are Gm- and rod shaped of 1-31μX0.5-0.8μ in size. They are motile with peritrichous flagella except one type S. gallinarum pullorum which are always non-motile. They do not form capsules or spores but may possess fimbriae. Salmonellae are aerobic and facultatively anaerobic growing readily on simple media over a range of pH 6-8 and temperature 15-41°C (optimum 37°C). Colonies are large, 2-3 mm in diameter, circular and smooth. On MacConkey and deoxycholate citrate media colonies are colorless due to absence of lactose fermentation. On Wilson and Blair bismuth sulphite medium, jet black colonies with a metallic sheen are formed due to production of H2S. S. paratyphi A and other species do not form H2S, produce green colonies. Selenite F and tetrathionate broth are commonly employed as enrichment media.

Introduction
Salt-affected soils (SAS) can be found across different latitudes, exhibiting variations in morphology, biology, and chemical, physical, and physicochemical properties (Gupta and Gupta, 2017). Despite their diversity, SAS share a common characteristic: the dominant role of soil solution electrolytes in the soil formation process, leading to properties that create unfavorable conditions for the normal growth of most plants (Szabolcs, 1989). In cases where SAS develop due to natural geomorphological processes, certain plant species, known as halophytes, have evolved specialized physiological adaptations to survive in these environments. Halophytes are capable of thriving in highly saline habitats by effectively managing the stress caused by excessive salt. Plants growing in such conditions employ various adaptive mechanisms to tolerate and flourish despite the salinity challenge. Salt-affected soils (SAS) require specialized management strategies to mitigate the challenges posed by high salinity levels. Plants and organisms in these ecosystems have evolved various adaptations to manage salt levels, such as developing specialized root structures, eliminating or containing excess salt, and efficiently absorbing water and nutrients (Flowers and Colmer, 2015). Despite their typically low alpha-diversity, SAS ecosystems contribute significantly to beta-diversity due to the specialization of organisms that thrive in such challenging environments. However, many of these high-value ecological systems have been severely degraded worldwide as a result of various political and economic decisions. For example, mangroves in countries like Thailand, Vietnam, Mexico, and Ecuador have been destroyed to make way for shrimp farming (FAO, 2007). Sabkhas around the Mediterranean coast have suffered from overexploitation of the aquifers that sustain them, and the reduction of water flow to closed drainage basins, such as in the case of the Aral Sea, has occurred due to water being diverted for irrigation, especially for cotton farming. Further degradation is seen in the transformation of SAS wetlands into agricultural fields through drainage, a practice observed in many regions (Mitsch and Gosselink, 2007). These ecosystems, once considered wastelands

Technical Term          Definition

Soil                             Soil is the superficial unconsolidated and usually weathered part of the mantle of a planet and especially of the earth

Salt affected soils can be defined as the soils containing excess amount soluble salts in their profiles in a proportion that adversely affect to soil properties and ultimately on crop growth. The soluble salts present in these soils are composed primarily with calcium, magnesium and sodium as cationic and chlorides sulfates and carbonates as anionic constituents along with the presence of potassium, nitrate and others as minor quantities. All soils invariably contain some soluble salts, but they cause harmful effects on crop growth only when accumulates in excess amount in soil solution or increase their concentration in exchange complex of the soil. Based on the presence of sodium salts and the predominance of sodium in the exchange complex, salt affected soils are classified into main categories of 1) Saline soils – contain excess soluble sodium in soil solution with little or no sodium content in exchange complex, 2) Alkaline (Sodic) soils – contain appreciable quantity of sodium adsorbed in exchange complex of soil but may or may not contain soluble sodium salts in soil solution. These soils are also divided into following types –

    1.    Salt affected soils;
    2.    Classification of salt affected soils; 
    3.    Formation of salt affected soils; 

Poor quality of water is one of the important factors causes gradual accumulation of salts on the ground or in the root zone of crops leads to saline and alkaline condition. This results in loss of permeability, toxicity and anaerobic conditions. In salt affected soils plants face constraint to derive their nutrients at the required rate due to high soil moisture tension, which affects adversely the crop growth and productivity.

Poor quality of water is one of the important factors causes gradual accumulation of salts on the ground or in the root zone of crops leads to saline and alkaline condition. This results in loss of permeability, toxicity and anaerobic conditions. In salt affected soils plants face constraint to derive their nutrients at the required rate due to high soil moisture tension, which affects adversely the crop growth and productivity.

10.1 Causes of Salt Problems

The following are the reasons for causing the soils become saline or alkaline.
1. Rise in water table: A rise in water table and high evaporation and transpiration rates with poor drainage lead to build up dissolved salts.
2. Quality of irrigation water: Irrigation water contains the dissolved salts exceeding certain limit cause accumulation of salts in soil profile.

12.1 Introduction

Rainfall is the major source of water that contributes lion’s share for irrigation to crops. Before it reaches the earth, it is to a great extent pure in nature. By the time it falls on the ground surface, it comes in contact with various types of gases and suspended materials of the atmosphere and also after it flows as runoff on the surface it gets dissolved with many types of salts, impurities etc. that render the water to be impure. Many a time the industrial waste, agricultural wastes, pesticides, fungicides, chemical fertilizers etc. get mixed with water and make it unsuitable for irrigation use. Water being a universal solvent, it dissolves all most all organic impurities, salts etc. which makes it objectionable for both domestic and agricultural uses.

Irrigated agriculture is dependent on an adequate water supply of usable quality. In the past, water quality concerns were neglected because good quality water supplies were plentiful and readily available. This situation is now changing in many areas. Especially, in the arid and semi-arid zones, water quality is fast deteriorating which is posing threat to irrigated agriculture.

Conceptually, water quality refers to the characteristics of a water supply that will influence its suitability for a specific use. On the other hand, it refers to the situation of how well the quality meets the needs of the user. There are three quality indicators. They are physical, chemical and biological indicators. Even a personal preference such as taste is a simple evaluation of acceptability. For example, if two drinking waters of equally good quality are available, people may express a preference for one supply rather than the other; the better tasting water becomes the preferred supply. In irrigated agriculture, emphasis is placed on the chemical and physical indicators of the water and rarely the biological indicator is considered important.

2.1. INTRODUCTION

Salt stress has become an ever increasing threat to food production. It is a major factor limiting the crop productivity in the arid and semi-arid areas of the world (Ashraf, 1994; Foolad and Jones, 1992) and it affects about 10% of the total global land area (Richards, 1995). Increased salinization of arable lands is expected to have devastating global effects, resulting in 30% land losses within the next 25 years and up to 50% by the year 2050 (Wang et al., 2003).

Soluble salts can cause harm to plant, if they are in high concentration in water or soils and it limit crop cultivation world wide. Generally an array of stresses interplay in saline soils and reduces productivity of salt sensitive crops. In India, about 12 mha of land has been affected with salinity and alkalinity (Yadav and Gupta, 1984); an area of nearly 4 mha of land suitable for rice affected with salinity (Paul and Ghosh, 1986). The optimum salt concentration for the growth of halophytes is found to be about 0.5 M NaCl (Flower and Yeo, 1981). Most of the crop plants are salt sensitive glycophytes.

Introduction

The need for water for human consumption and the industry keeps spiraling up in the cities in the wake of rural diaspora and urban sprawl. Groundwater is exploited at an unsustainable rate leading to depletion of aquifers. Worse still is the intrusion of salt water from adjoining coast into the aquifers leading to total wastage of remaining water.

Introduction

Accumulation of excess soluble salts in the root zone of soils resulting in partial or complete loss of soil productivity is a worldwide phenomenon. The problems of soil salinity are widespread in the arid and semi-arid areas but salt-affected soils also occur extensively in the sub-humid and humid climates particularly in the coastal regions where the ingress of sea water through estuaries and rivers and through ground water movement causes large scale soil and water salinisation. Soil salinity is also a serious problem in areas where ground waters of high salt content are the only source of water available for irrigation. By far the most serious problems of salinity are being faced in the irrigated, arid and semi-arid regions of the world. Our ability to manage salt-affected soils and waters both in the irrigated and in the unirrigated regions will constitute a major effort in meeting potential food requirements. The magnitude of the problem can be appreciated from the following.

The use of salt (Sodium Chloride) in food products is an important method of preservation. It not only imparts taste to the products but also helps in checking spoilage of fruit products. Salt is added to pickles, sauces, chutneys, ketchup, and many other products. Food Safety & Standards Regulation has specified the maximum limit of salt in different products. Therefore, the estimation of salt content in food products is considered as an important attribute in food quality control.
Direct Titration Method
Direct titration (Mohr’s) method is used for the determination of salt content in food products as a routine quality control. In this method, the sample is titrated against a standard solution of silver nitrate for the estimation of salt.
Reagents
0.1 N NaOH, Phenolphthalein 1% indicator solution
0.1N Silver nitrate (AgNO3)
5% Potassium Chromate

Next to the mineral frame work the salts in the soil deserve consideration. In fact these salts constitute the main food material of plants besides what the root hairs can get out of the mineral framework in the form of basic materials already dealt with. We are, however, not concerned with the plant food materials, but salts that are in excess and which alter the properties of the soil to such an extent as to influence its behaviour profoundly.

Salvadora the  “Grape of the Desert” and commonly known as Pilu or jaal is a popular  multipurpose tree (MPTS) found growing luxuriantly in Thar desert and Kutchh region of Gujarat. It is an extremely drought hardy and salinity tolerant plant, capable of growing in hostile weather conditions. Salvadora provides life and support to the people living in fragile ecosystem of Thar desert and hence can be rated as a life line tree. The two important species of Salvadora i.e. Salvadora oleoides Decne and Salvadora persica L. are known to exist in India and known by different vernacular names. S. oleoides is called jaal, Mitha jal (Rajasthani); Pilu (Sanskrit); Bhapilu (Hindi); Kankhina (Marathi); Pil (Punjabi) and Kalawa (Tamil) while S. persica is known as Pilu (Sanskrit), tooth brush tree (English); Chotapilu (Bengali); darakht-I-miswak (Persian); Pilu (Marathi); Varagogu (Telgu) Ughaiputtai (Tamil); goni-mara (Karnataka). Salvadora is native of India, East Africa and Arabia. It is found in wild form in extensive areas of Africa particularly, Turkama, Sambura and Marsabit districts of Northern Kenya, Ferli in North Senegal, South Sivani in Egypt and N. E. Tanzania. Salvadora is also of common occurrence in South coastal areas of Pakistan, Sindh and Baluchistan, Saudi Arabia and other middle eastern countries.

Once a pest, pathogen or a weed has been detected in the introduced planting material, quarantine officials must make all efforts to disinfect/decontaminate the material and make it available for further exploitation in the country without undue delay. However, it may be kept in mind that treatments, which only reduce the inoculum, may be acceptable for general agricultural practices, but they are not acceptable in plant quarantine. For quarantine purposes, tolerances are zero and, therefore, no residual inoculum of exotic pests/pathogens must remain. Fullproof eradicative treatments are required to be employed before release of the planting material from quarantine.

16.1. Fumigation

Fumigation of the material under atmospheric or under reduced pressure has been found acceptable as a quarantine treatment against insects and mites. Fumigants like methyl bromide, HCN, phosphine and EDCT (ethylene dichloride + carbon tetrachloride mixture) are commonly used.

In general, fumigation with Methyl bromide at 48g/cubic metre for 24 hours at 21ºC or above or 32g/cubic metre for 2 hours at 21ºC or above is used based on the kind of infected material and the pest to be salvaged.

Salvia belongs to family Lamiaceae. The genus Salvia comprises about 900 species which are grown for their ornamental flowers since they make excellent and showy borders in gardens. One of the species most commonly grown is Salvia splendens is a tender herbaceous perennial, but grown in India as winter season annual flowering plant. It bears racemes of bright scarlet flowers of large size. It has ability to grow under partial shade condition. It is commonly grown as bedding plant due to varying colours mostly scarlet, purple, orange, lavender and yellow and long lasting flowers. The word salvia was derived from Latin word ‘Salvare’ meaning ‘to heal or to be safe and unharmed’ (Blumenthal et al., 2000 and Kamatou et al., 2008) later it was translated in French as “sauge” or “sage” and in old English “Sawge” (Kamatou et al., 2008).

Salvia belongs to family Lamiaceae. The genus Salvia comprises about 900 species which are grown for their ornamental flowers since they make excellent and showy borders in gardens. One of the species most commonly grown is Salvia splendens is a tender herbaceous perennial, but grown in India as winter season annual flowering plant. It bears racemes of bright scarlet flowers of large size. It has ability to grow under partial shade condition. It is commonly grown as bedding plant due to varying colours mostly scarlet, purple, orange, lavender and yellow and long lasting flowers. The word salvia was derived from Latin word ‘Salvare’ meaning ‘to heal or to be safe and unharmed’ (Blumenthal et al., 2000 and Kamatou et al., 2008) later it was translated in French as “sauge” or “sage” and in old English “Sawge” (Kamatou et al., 2008). Salvia has several ornamental, culinary and medicinal species (Codd, 1985, Paton, 1991, Gali-Muhtasib et al., 2000, Kamatou et al., 2008 and Bruna et al., 2006). It is also used in preservation of food, mainly meat and cheese, due to its antioxidant properties, as well a spice for flavouring food articles (Topuc, 2006). Chinese use its species to increase longivity and Roman use it in ceremonies as scared herb (Kamatou et al., 2008). The salvia species contain secondary metabolite the main are terpenoids and flavonoids and monoterpenes present in aerial parts of plant like flower and leaves and diterpenoids mostly in roots (Topuc, 2006).

ORIGIN AND DISTRIBUTION

The centre of origin of salvia is considered to be Afghanistan and Soviet Central Asia as a large number of primitive morphological species are present but the most of the diversity or species are present in Mexico (Paton, 1991 and Kamatou et al., 2008). The genus is sub-cosmopolitantly distributed worldwide, but is absent in the North and most of the low-lying tropical areas of the world such as the Amazon basin and central and west Africa (Paton, 1991), Jager and Van Staden (2000) and Kamatou et al. (2008) reported its absence not only in western Africa but also in central tropical Africa, Hedge (1974) and Kamatou et al. (2008) reported that West and the southern parts of Africa has greatest number of species (Kamatou et al., 2008).

The genus Salvia contains at least 900 species, because they readily cross pollinate, innumerable hybrids - both natural and manmade. Salvias are found on almost every continent in the world. Pliny the Elder, a Roman naturalist, wrote about their healing qualities back in the first century. In the early 17^th century, the English botanist John Gerard, in his famous Herbal, described a number of sages, including common garden sage and one that sounds similar to what we now call ‘Tricolor’ sage. He referred to the healing powers of these herbs as well. Until the 19^th century, most gardeners focused on growing plants for medicinal or culinary purposes; beauty was a secondary, much less important consideration.

The results of plant exploration in the 18^th and 19^th centuries brought scores of new salvias to English and European gardeners from Mexico, China and Africa. One, Salvia buchananii, was found in Mexico by an English woman, who gave it to a man serving in the army. Salvia coccinea, indigenous to Mexico and South America, was grown for decades as a wildflower. Both scarlet sage and mealy cup sage were discovered in the early 1800’s, the former in Brazil, the latter in Texas.

Abstract: Ornamental salvia, native to Brazil is cultivated as bedding plant in the world. Many species have horticultural, commercial and medicinal values. Continued breeding and improvement of salvia is focused on disease resistance, new flower colours, seed oil content and abiotic stress tolerance. Interspecific hybridization is hampered by genomic differences, heterostyly, self incompatibility and low seed set. Breeders have created polyploid cultivars and mutants which have high ornamental value. Continued use of these and other modern techniques will ensure creation of new phenotypes for the market.

Keywords: Salvia, polyploidization, male sterility, inheritance, seed production.

The study and utilization of biomass for energy, composting, or other valueadded applications require accurate information about its properties. This begins with a scientifically sound process of sample collection, preparation, and analysis. Each step ensures that the data derived from biomass materials is representative, reliable, and applicable for research, industrial application, or environmental assessment.
Sample Collection
Biomass sampling methods vary depending on the biomass type and the analysis objective. For instance, truck-top sampling is used for biomass pellets, while quadrats are employed to gather cover crop biomass from fields. Regardless of the technique, the primary aim is to collect a representative sample that accurately reflects the overall characteristics of the biomass.
Purpose
The goal is to obtain a sample that accurately represents the average composition and properties of the entire biomass batch.
Biomass Types Commonly Sampled
• Agricultural by-products (e.g., husk, straw, stubble)
• Animal-derived waste (e.g., manure, poultry litter)
• Forest residues (e.g., bark, wood chips) • Organic or food waste
• Industrial biomass (e.g., bagasse, distillery by-products) Sampling Guidelines
• Random Sampling: Collect from multiple locations within a pile or batch to reduce sampling bias.
• Quantity: Gather a sufficient amount—typically several kilograms—based on whether physical, chemical, or energy content analysis is intended.
• Equipment: Use clean, non-corrosive tools such as stainless steel or plastic scoops.
• Preservation: Store in sealed containers or bags to maintain sample integrity and prevent contamination or moisture changes.

Scanning electron-microscopes are available nowadays which operate at high vacuum as well as low vacuum mode. Low vacuum mode allows viewing of wet samples, but compromise on very high resolution and high magnification images. In high vacuum mode the samples must be absolutely dry and free of any organic contaminants to avoid gas molecules interfering with both the primary electron beam and the secondary or backscattered electrons emitted from the sample. Biological specimens which are largely composed of water, necessitate additional preparatory steps to ensure that structure of the organism is retained in its natural form.
Sample preparation is essential in scanning electron microscopy. Improper sample preparations can undermine the quality of results and lead to false conclusions. SEM, unlike TEM, allows the processing of larger sized organisms and tissues. For Biological samples the smallest representative sample size should be used as the microscope’s detection capacity is as much as 1μm from the sample surface.
Samples for SEM preparations are normally collected by biopsy/ dissection/ sacrificing of an animal to remove tissues from the main body. Incisions should be done with fresh sharp blades to avoid tissue deformation from the physical forces applied with blunt blades. Collected samples should be immediately transferred to vial containing the fixative for fixation.
Microbial cultures fixation of bacteria and fungus needs to be carried out under strict safety measures. Biosafety cabinets should be used wherever possible and sample should be removed from the biosafety cabinets only after the

The preservation methods used for water samples differ depending on the experiment to be performed, and they are as follows:

1. Project is __________

a) Investment activity

b) Create productive assets

c) Realising benefits over time

d) All of these

Q.1 SRSWOR scheme is better (more efficient) them SRSWR scheme.

Q.2 The sampling variance of sample mean under SRSWOR scheme is more than that in SRSWR scheme.

.3 The sample variance s2 is an unbiased estimate of population M.S. (S2 ) in case of SRSWOR scheme.

4.1. INTRODUCTION

The number of individuals to be included in a research study (the sample size of the study), is an important consideration in the design of many studies. This chapter will provide information on basic factors that determine an appropriate sample size and provides methods for its calculation in some simple, yet common, cases. Sample size is closely tied to statistical power, which is the ability of a study to enable detection of a statistically significant difference. A trade-off exists between a feasible sample size and adequate statistical power. Strategies for reducing the necessary sample size while maintaining a reasonable power is also important.

How many individuals will I need to study? This question is commonly asked by the clinical, ecological and behavioural investigator and exposes one of many issues that are best settled before actually carrying out a study. Consultation with a statistician is worthwhile in addressing many issues of study design, but a statistician is not always readily available.

The amount of information that can be gained from a sample depends upon its absolute size and not upon its size as a proportion of the population size, Just as to decide if the wine is good we need only a sip, irrespective of the bottle size, similarly we do not need to know the exact size of the parent population, provided complete homogeneity exists, But in reality, and more so in biological sciences, such homogeneity is rarely seen. Therefore, appropriate sample size becomes pertinent for drawing valid conclusions and is among the most difficult decisions to be taken for a study.

The size of the sample would depend upon (i) the permissible error in assessment of inference i.e. accuracy and (ii) sampling error. Sampling error measures the amount of variability between sample results; the lesser it is the better. The main determinant of the sample size, therefore, is how accurate results do we used. This in turn, depends on the purpose and type of study.

True/False

Q.1.    The precision of an estimator increases as the sample size increases.
Q.2.    Statistical power is the probability that a statistical test will indicate a significant difference is true i.e. it is the probability of taking correct decision.

In this chapter some preliminary terminologies have been provided which are very much useful and frequently used in dealing with the theory of sample surveys and its application.