eChapters

Principle

Pesticide residues in milk are derived from the intake of pesticide contaminated feed and fodder.

Scope

This method is suitable for most OPs, OCs, SPs, and herbicides residue analysis.

Principle

Pesticide residues are extracted from soil using a mixture of acetone/water in a soxhlet apparatus for 7-8 hours. This extract can be determined directly by GLC.

Scope: This method is suitable for most OPs, OCs, SPs, and herbicides residue analysis.

India is recovering from the euphoria of the Green Revolution and battling the residual effects of the extensively used chemical fertilizers and pesticides in the country’s soils. The decade from 1980 to 1990 alone saw the area under pesticides in India, increased a whopping 20-fold, from six million hectares to 125 million hectares. After a high annual consumption of nearly 75000 MT reached in the early ’90s, interventions in the form of Integrated Pest Management (IPM) practices have only now started to show a declining trend in the use of pesticides in India. Interestingly, India’s consumption of pesticides per hectare is low (0.288 kg/ha) when compared with world averages—0.5 kg/ha against Korea’s 6.60 kg/ha and Japan’s 12.0 kg/ha. According to the pesticides industry statistics, India spends US $3/ha on pesticides compared with US $24/ha spent by Philippines, US $255/ha spent by South Korea and US $633/ha by Japan. Yet, despite a comparatively low use of pesticides in India, the contamination of food products in the country is alarming. About 20 per cent of Indian food products contain pesticide residues above tolerance level compared to only 2 per cent globally. No detectable residues are found in only 49 per cent Indian food products compared to 80 per cent globally. A pesticide is any substance or mixture of substances intended for preventing, destroying, repelling or mitigating any pest. Though often misunderstood to refer only to insecticides, the term pesticide also applies to herbicides, fungicides and various other substances used to control pests.

Pesticides and their metabolites have received particular attention in the last few years in environmental trace organic analysis because they are regularly detected in food products, surface/ground waters and soil strata throughout the world as consequence of their widespread use for agricultural and nonagricultural purposes. So it is the need of the hour to study the levels of pesticides residues in plants, water and soil and their fate in environment after its degradation.

It would be necessary to work out tolerance limits of pesticides residues in/on crops, soil and water and the efforts, therefore, are directed towards various residue analytical methods like TLC, GLC and HPLC etc. which are suitable for the purpose.

A pesticides residue is any substance or mixture of substances in food, agricultural commodities or animal feed resulting from the use of pesticides and includes any specified derivatives such as degradation products and impurities that are considered to be of toxicological significance.

Pesticide residue analysis (PRA) may be defined as the quantitative and qualitative analyses of the representative samples drawn from agricultural field, market and environment for pesticides and their toxic metabolites.

Principle: Acetone is used for extraction the most nonionic pesticide residue, and residue are partitioned from acetone to dichloromethane/hexane phase. After removing traces dichloromethane, final extract is made up with acetone. This extract can be determined by GC with selective detectors FPD-P/NPD without cleanup. Further for organochlorine and synthetic pyrethroids extract should be cleaned up using florisil column. And for determination organophosphate extract should undergo to charcoal-celite cleanup.

Pesticides are used to control plant growth (herbicides), insects (insecticides), worms  (vermicides), bacteria (bacteriocides), fungi (fungicides), and other organisms. Almost without exception, pesticides are used to benefit humans by the control of unwanted species of plants (e.g. weeds in a lawn), disease-causing bacteria (e.g., Pneumococcus, the causative agent of pneumonia), disease-carrying insects (e.g. malarial or yellow fever mosquitoes) or in controlling destruction of agricultural products by disease-causing organisms (e.g., corn-borers, the virus of anthurium blight). Although they are by and large mostly beneficial, pesticides used both properly and improperly are also “resources out of place”, that is pollutants, that are subject to normal ecological processes.

10.1. Classification of pesticides

10.1.1. Based on organisms

Though a large number of insect pests are reported to attack mango, which cause considerable damage to mango crops in India. More than 492 species of insects, 17 species of mites and 26 species of nematodes have been reported to be infesting mango trees, about 45 per cent of which have been reported from India. Almost a dozen of them have been found damaging the crop to a considerable extent causing severe losses and, therefore, may be termed as major pests of mango. These are hopper, mealy bug, inflorescence midge, fruitfly, scale insect, shoot borer, leaf webber and stone weevil. Of these, insects infesting the crop during flowering and fruiting periods cause more severe damage. The insects other than those indicated above are considered as less injurious to mango crop and are placed in the category of minor pests. A brief description of the biology and control of major pests of mango is given below. Mango suffers from several diseases at all stages of its life. All the parts of the plant, namely, trunk, branch, twig, leaf, petiole, flower and fruit are attacked by a number of pathogens including fungi, bacteria and algae. They cause several kinds of rot, die back, anthracnose, scab, necrosis, blotch, spots, mildew, etc. Some of these diseases like powdery mildew are of great economic importance as they cause heavy losses in mango production. Major pests and diseases of mango and their control measures are discussed below.

3.1. Paddy

3.1.1. Thrips: Stenchaetothrips biformis (Thripidae: Thysanoptera)

6.1. Cotton

6.1.1. Leafhopper: Amrasca devastans (Cicadellidae: Hemiptera)

5.1. Groundnut

5.1.1. Aphids - Aphis craccivora (Aphididae: Hemiptera)

4.1. Black gram, green gram, lablab and cowpea

4.1.1. Bean aphid: Aphis craccivora (Aphididae: Hemiptera)

1. Host range: Groundnut, redgram, peas, beans, safflower, lablab, niger

7.1. Early shoot borer: Chiloinfuscatellus snellen

1. Damage symptoms

2.1. Causes of pest outbreak

Activity of human beings which upsets biotic balance of ecosystem is prime cause for pest outbreak.

pH is defined as the negative logarithm of hydrogen ion concentration. The amount of the acidic gas CO2 significantly affects the pH of natural water body. Fish have usually blood pH levels of 7.4, but little deviation has been observed, perhaps 7.0 to 8.5pH range is more suitable for the growth and reproduction of the fish. However, pH range 4.0 to 6.5 and 9.0 to 11.0 cause fish death in water pH less than 4.0known as acidic death point or even more than 11.0 known as alkaline death point. The pH of fresh water more fluctuating as compare to sea water due to release and consumption of CO2 and O2 respectively by bacterial oxidation and respiration. However, the pH of marine water often constant at 7.8-8.3 due to presence of buffer like HCO3-, CO2 -, CO3-2 etc.
Principle
The estimation of hydrogen (H+) ion activity through sensing electrode. Electrode composed of a narrow glass bulb with fixed concentration of HCI solution inside it. A wire made of an Ag-AgCI placed in to the bulb which work as electrode to fix voltage. Potential difference forms between the solution in the glass bulb and the sample solution when the electrode immersed into solution.

Introduction

Agricultural produce are being sun dried since ages as the first step to preserve the product for future consumption. It is still practised being most inexpensive over mechanical and other advanced drying systems. The most prevailing disadvantage of open sun drying is the quality losses due to insect infestation, enzymatic reactions, microorganism growth, and mycotoxin development. On the other side, sun drying is also a highly labor intensive and time consuming process prone to theft and damage by birds. It also suffers with the lack of process control and treatment uniformity (Bansal and Garg 1987, Bansal, 1987).

To overcome these disadvantages several types of solar dryers have been developed over the years (Ekechukwu and Norton 1999). These dryer may be identified into three group namely active, passive and hybrid. As regards their structural arrangement three generic subclasses were also identified: direct-modes (the solar-energy collection unit is an integral part of the entire drying system), indirect-modes (the solar collector and the drying chamber are separate units) and mixed-modes solar dryers. Natural convection solar dryers have become more suitable for rural sector and remote areas, as they work on single energy option and do not require any other external energy source (Pangavhane et al. 2002).

Introduction

As the most of the conventional resources are depleting and can last only for about a few 30 to 50 years. Scientists worldwide are looking for alternative energy resources and they have come to an agreement that solar energy can provide much of our energy needs in the future. The major challenge before them is to store this energy. The radiation falling on the earth surface can be tapped and stored in no of ways. However, the most efficient way is done through the latent heat storage through PCM. The PCM has many added advantages i.e. high energy density, isothermal behavior, non-polluting and low cost. Nowadays, it gaining popularity worldwide and now seen as the most efficient way of thermal energy storage. There is a large number of PCM at use i.e. organic, inorganic, eutectic and salt hydrates. Their utilization depends on the user’s requirement technological constraints. They also serve the purpose of energy availability at night beside the uninterrupted supply during the day. They are seen as the materials for ensuring the environmental sustainability

1. Introduction

The agricultural sector plays a pivotal role in driving economic development in India, a nation with a population of 1.39 billion, making it the world’s second most populous country according to the United Nations’ World Population Prospects 2019. With 54.6 percent of the workforce engaged in agriculture as per the 2011 Census, and contributing 18.6 percent to the Gross Value Added (GVA) in 2021-22, its significance cannot be overstated. Notably, women play a substantial role in this sector, with rural females exhibiting a higher workforce participation rate of 41.8 percent compared to 35.31 percent for urban women (MoSPI, 2017). In rural communities, agriculture and allied sector is the primary source of livelihood that includes 80 percent of all economically active women, out of which 33 percent constitute agricultural labour force and 48 percent are self-employed farmers. Rural women are engaged at all levels of the agricultural value chain; i.e., production- pre-harvest, post-harvest, processing, packaging, marketing to increase productivity in agriculture (Nilam Patel etal, 2022). As per Pingali et al. (2019), the ratio of women to men working in the agricultural sector has increased over the time and made a greater amount of contribution to GDP per capita. They are the momentous demographic group for a sustainable food system (FAO, 2011). Empowering women in agriculture through reforms aimed at ensuring equal access to resources, skill development, and opportunities is projected to increase agricultural output in developing countries by 2.5 to 4 percent (FAO, 2011).

Plant growth is resultant of all the environmental factors – climatic, physiographic, edaphic and biotic factors.

For a particular field – it is primarily a function of climate with temperature and light – being the most important factors. – Close relationship exists between plant phenology and both latitude and altitude.

Introduction

Mosquito-borne diseases such as malaria, filariasis, Japaneseencephalitis, chikungunya and dengue hemorrhagic fever cause extensive morbidity and take heavy toll of life in the developing nations particularly in the tropics. Every year about 300-500 million people are estimated to be affected by malaria alone (WHO report, 2000). In India around two million cases of malaria are being reported annually although real burden is many fold higher (Kumar et al. 2007). Similarly, lymphatic filariasis caused by Wuchereria bancrofti affects about 120 million people worldwide. India contributes about 40%  to  the total global burden of filariasis and accounts for about 50% of the people at risk of infection (ICMR bulletin, 2002). Anopheles stephensi is recognized as a major vector for urban malaria in India (Kumar 1997).

Semiochemicals are chemical substances that mediate communication between organisms.

Classified into pheromones (intra specific semiochemicals) and allelochemicals (inter specific semiochemicals).

Acid and alkaline phosphatase enzymes are among the extensively studied phosphatases and classified so because of their optimum activities in acid and alkaline pH ranges, respectively. Acid phosphatase is predominant in acid soil while alkaline phosphatase is dominant in alkaline soils. The colorimetric assay of phosphatase is based on release of p-nitrophenol from hydrolysis of p-nitrophenyl phosphate byaction of phosphatase enzyme in buffered soil solution (buffer pH 6.5 for acid and 11 for alkaline phosphatase assay).

Introduction

Increased population pressure, reduced length of fallow, deforestation and improper agricultural practices have led to widespread soil degradation in many parts of the developing world which has culminated in appearance of determinative manifestations of environmental damage in form of inadequate replenishment of soil nutrients and organic matter. Phosphorus is second major plant growth limiting nutrient and despite being in abundance in soil (organic and inorganic form), P deficiency is becoming critical in many soils throughout world as these soils have free available P concentration (generally) not higher than 10mM even at most soluble slight acidic pH (Arnou, 1953). Moreover, consistent P deficiency threatens to disturb the use efficiency of applying other nutrients. Hence to preserve the sustainability of agriculture it is foremost to rebuild soil fertility and maintain/improve the soil biodiversity to reap hiked current levels of productivity and farm income.

Phosphorus (P) is the second most important essential nutrient limiting crop/ plant growth, next only to nitrogen (N). Phosphorus is an important component of nucleic acid like deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). It is needed for energy storage and transfer, which is the single most important essential function of P. Phosphate compounds act as “energy currency” within plants. The most important common P energy currency is adenosine diphosphate (ADP) and adenosine triphosphate (ATP). The ATP transfers energy for synthesis of ADP. Life is not possible without P. It is the source of energy that powers practically all energy-requiring biological processes in plants. Phosphorus is present in plant as phospholipid such as lecithin and cephalin which appears to be involved in the structural framework of protoplasm. Phosphorus is involved in many important processes such as photosynthesis, cell division, tissue development, and growth in plant. Requirement of P by the crops is less, compared to N and potassium (K). It is present in plant tissues. It is reported that for 5-6 t ha^-1 of wheat grain yield, it removes about 100-120 kg N, 20-30 kg P₂O₅ and 150-180 kg K₂O from soil.

Phosphorus is 11^th most abundant element on the earth crust. However, it is the least mobile element among the major plant nutrients. Its complex chemistry in soil makes it highly deficient nutrient element in most of the arable soils across the globe. Only 0.1% of the total P in the soil is available for uptake by plants because of its fixation as various insoluble compounds depending upon the soil pH. About 43% of the world’s arable soil is P deficient which limits crop growth and production (Roy et al., 2018). In the Indian context, about 80% of the soils are reported to have low to medium available P content (Muralidharudu et al., 2011). Thus, application of P-fertilizers to maintain the soil fertility and sustain crop productivity becomes imperative in today’s input intensive agriculture.

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.

Phosphorus is present in soil both in inorganic form and organic form. The inorganic P can be divided into different pools. The major active inorganic forms are: P bound to aluminium (Al-P), iron (Fe-P), calcium (Ca-P) and silicate minerals and relatively less active forms are occluded and reductant soluble forms of P. On the other hand, the principal organic P compounds present in soil are (i) inositol phosphate, (ii)phospholipids, (iii)nucleicacid and other unidentified esters and phosphoproteins.

22.1 Determination of Available Soil P

The availability of soil P to plant varies greatly depending upon the reaction, minerological composition and amount of the soil colloid. Very little P is present in the soil solution except in recently fertilized or sodic soils. The type of phosphate ions present in the soil solution depends on the soil pH. In soils of neutral to slightly alkaline pH, HPO₄^2-ion is the dominant form. In slightly or moderately acidic soils, both HPO^-and HPO^2-ions prevail. At strongly acidic soil HPO 244 24 ion tends to dominate, while above pH 9.0, the PO₄^3-ion becomes more important - than H₂PO₄ .

As the P is drawn from soil solution largely through diffusion by the plant, it is replenished from solid phase pool of available P. P fertilizer is added to recharge this pool.

Phosphorus in soil present both in inorganic form and organic form. The inorganic P can be divided into different pools. The major active inorganic forms are: P bound to aluminium (Al-P), iron (Fe-P), calcium (Ca-P) and silicate minerals and relatively less active forms are occluded and reductant soluble forms of P. On the other hand the principal organic P compounds present in soil are (i) inositol phosphate, (ii) phospholipids, (iii) nucleic acid and other unidentified esters and phosphoproteins.

15.1. Determination of Available Soil P

The availability of soil P to plant varies greatly depending upon the reaction, minerological composition and amount of the soil colloid. Very little P is present in the soil solution except in recently fertilized or sodic soils. The type of phosphate ions present in the soil solution depends on the soil pH. In soils of neutral to slightly alkaline pH, HPO₄^2- ion is the dominant form. In slightly or moderately acidic soils, both H₂PO₄^- and HPO₄^2- ions prevail. At strongly acidic soil H₂PO₄^- ion tends to dominate, while above pH 9.0, the PO₄^3- ion becomes more important than H₂PO₄^-.

Phosphorus is essential for plant growth and is involved in important physiological processes, but its availability in soil is strongly influenced by soil chemical conditions. This chapter provides a systematic treatment of phosphorus management in irrigated soils. It begins with the functions of phosphorus and the classification of soil phosphorus into organic and inorganic forms. The behaviour of phosphorus in alkali soils is discussed along with phosphate fixation, which can substantially influence phosphorus availability to crops. The chapter examines the sources of soil phosphorus used by plants and the major types of phosphatic fertilizers used in agricultural production. Available and total phosphorus are distinguished, providing a basis for assessing soil phosphorus status. The behaviour of phosphate fertilizers after application is considered in relation to their efficiency and crop uptake. The residual value of phosphatic fertilizers is also discussed, highlighting the continuing contribution of applied phosphorus to subsequent crops. Overall, the chapter emphasizes efficient phosphorus management to improve nutrient availability, fertilizer-use efficiency and sustainable crop production in irrigated soils.

Phosphorus is the second important key element after nitrogen as a mineral nutrient in terms of quantitative plant requirement (Donahue et al., 1990), which is required in optimum amount for proper growth of plants and soil micro-organisms. Being a constituent of ATP, it is involved in various processes such as cell division, energy transduction through photosynthesis and biological oxidations and uptakeof nutrients. The average soil contains 0.05% phosphorus, but only one tenth (1/10) of this is available to plants due to its poor solubility and chemical fixation in soil (Barber, 1984). About 98% of Indian soils have inadequate supply of available phosphorus (Ghosh and Hassan, 1979). A survey of Indian soils showed that out of 363 districts, only 2.2% were high, 51.5% medium and 46.3% were low in phosphorus content (Ghosh, 1982).

Phosphorus is one of the essential plant nutrients, which is required in optimum amounts for proper growth of plants and soil biota. Being a constituent of ATP it is involved in various processes such as cell division, energy generation and transfer of genetic characteristics and regulation of metabolic pathways (Theodorou and Plaxton, 1993). Phosphorus constitutes about 0.2% plant dry weight (Schachtman et al., 1998). The average soil contains 0.05% phosphorus but only one tenth of this is available to plants due to its poor solubility and chemical fixation in soil (Narayansamy et al., 1981, Barber, 1984). About 98 percent of Indian soils have inadequate supply of available phosphorus (Ghosh and Hasan 1979, Hasan, 1994). A survey of Indian soils showed that out of 363 districts, only 2,2% were high, 51.5% medium and 46.3% were low in phosphorus content (Ghosh 1982).

The problem of P fertilization may become serious in coming years because of the fact that manufacture of phosphatic fertilizers requires the use of non renewable resources such as high grade rock phosphate and sulphur which are becoming costlier. The situation is further aggravated by the fact that P is readily fixed in the soil and the average utilization efficiency of added fertilizer P by plants ranges from 15-25% only (Gaur 1982, 1990). The recent report showed that 42 per cent of soil samples fell in low category, 38 per cent in medium and 20 per cent in high category (Motsara, 2002). It has been observed that the vast alluvial tracts of the country are either low or medium in available P. Hence they need P application at recommended rates.

Phosphorus (P) is a critical nutrient in crop production, due to its low bioavailability in soils (Feng et al., 2004). Phosphorus is the vital component of DNA, RNA, ATP and photosynthetic system and catalyses a number of biochemical reactions from the beginning of seedling growth through to the formation of grain and maturity. Many factors influence soil P availability like type of parent material from which the soil is derived, degree of weathering and climatic conditions. In addition to this, erosion, crop removal and phosphorus fertilization and soil phosphorus levels also affect P availability in soil. Rock phosphate is the key raw material used for manufacturing phosphatic fertilizers on which the food production depend.

Liebig (1840) on the basis of soil and plant analysis deduced the phosphorus requirement of plants. J.B. Lawes conducted series of field experiments to improve the fertilizer value of common sources of phosphorus such as bone meal, apatite, rock phosphate. Lawes (1843) produced super phosphate by treating apatite mineral containing phosphorus with sulphuric acid. He also stated that the phosphorus present in bones of higher animals can be made available by treating with sulphuric acid.

Phosphorus is the second most deficient nutrient in the world. Annual application of phosphorus fertilizers to crops is 36 million tons of which

1.32 m tones are consumed in India. Most of the arable soils in tropical and subtropical regions are deficient in phoshphorus, but the response of crops to phosphorus is uncertain. Phosphorus concentration in plants ranges from 0.1 to 0.4 per cent.

1. Introduction
Water is the most essential resource for life, supporting the survival of allliving beings, including humans, and playing a crucial role in food productionand economic progress. Currently, many cities around theworld are facingsignificant water shortages. About 40 % of global food production dependson irrigation, and countless industrial operations rely heavily on water. Theavailability and quality of water, whether surface or groundwater, have amajor impact on environmental health, economic development, and societagrowth. Human activities like urban expansion, population increase, industrialoutput, and climate shifts are causing a decline in water quality. As nationsdevelop, industrial activities increasingly lead to the pollution of watersources, resulting in negative consequences such as widespread disease and
diminished beauty of water bodies. This pollution is a significant threat toboth the planet and its inhabitants. Higher temperatures are interfering with themetabolic processes of aquatic life, while changes in water pH create unstableconditions. Additionally, increased cloudiness in water reduces oxygen levels,affecting deep-water species and contributing to health issues for both animalsand humans. Polluted water also hinders growth and development in allliving organisms Haldar et al., 2015 and Arif et al., 2020. A study conductedby Halder et al. (2015) highlighted severe health challenges faced bylocalcommunities due to pollution in the Turag River, Dhaka, caused by thedischarge of untreated wastewater into the river. It was revealed that elevatedpH levels in the water, resulting from the use ofcaustic chemicals such assoda ash and caustic soda in industrial processes, were associated with skinirritation and sores. Dietary exposure to polluted crops and fish was found
to contribute to stomach ailments, including gastric ulcers. Concerns wereraised about potential groundwater contamination through the infiltration ofindustrial waste. Microbial contamination was identified as a likely cause ofdiarrhoea and dysentery. The use of river water for bathing and laundry wasobserved to facilitate the spread of waterborne diseases. Outbreaks of yellow
fever, cholera, dengue, malaria, and other epidemics were noted as prevalent inthe area. Respiratory problems and foul odours were attributed to air pollutioncaused by industrial discharge. Maternal and child health in riverbank slumsfound to be vulnerable, emphasizing the urgent need for interventions to addressthese public health concerns.Wastewater produced by industries, agriculture,and domestic activities contains high levels of nutrients, heavy metals, andchemicals, which harm the environment by polluting land, air, and water,

Abstract

Photosynthetic blooms of toxin producing marine algae are often referred to as “red tides”. Proliferations of freshwater toxin-producing cyanobacteria are simply called “cyanobacterial blooms” or “toxic algal blooms.” Biotoxins of cyanobacteria are water-soluble and heat stable and they are released upon aging or lysis of the cells. The primary types of cyanobacterial biotoxins involves three types of toxins: hepatotoxins (microcystin; cylindrospermopsin and nodularin), which are taken up by the liver and cause weakness and anorexia (loss of appetite); neurotoxins (usually anatoxin and saxitoxin), which effect the nervous system and dermatotoxins (aplysiatoxin and lyngbyatoxin, LPS), which cause skin and mucous irritations upon contact. Unlike freshwater toxic algal blooms, marine algal toxins become a problem primarily because they may concentrate in shellfish and fish that are subsequently eaten by humans, causing syndromes known as paralytic shellfish poisoning/PSP (paralysis due to saxitoxin and gonyaulatoxins), diarrhetic shellfish poisoning/DSP (diarrhea due to okadaic acid) , amnesic shellfish poisoning /ASP(memory disturbances due to domoic acid), neurotoxic shellfish poisoning/NSP (paresthesia due to brevetoxin; also bronchial spasms). Coral reef fishes are the vectors of another algal poisoning, the ciguatera fish poisoning/CFP (paresthesia, warm-cold sense inversion etc., due to ciguatoxins and maitotoxin).

Introduction to Nano-materials

Nano-sized materials are naturally present from forest fires and volcanoes, but are also generated unintentionally from anthropogenic sources as a by-product of combustion and deliberately as manufactured nanomaterials. Nanoparticles have been used for centuries. The coloured glass that we see in many old cathedrals from the middle age was made of gold nanosized clusters that created different colour depending on the size of the nanoparticles. The most prominent example of engineered nanoparticulate material is carbon black which has been around us for decades in applications like printing inks, toners, coatings, plastics, paper, tires and building products.
 
Two of the major factors why nanoparticles have different properties (optical, electrical, magnetic, chemical and mechanical) than bulk material are because in this size-range, the quantum effects start to predominate and the surface area to volume ratio is increased.

10.1 Different practices for different purposes

There are so many different practices used in erosion control that to describe them needs some form of grouping. For a long time mechanical protection was used to describe all the methods which involved earth moving, such as digging drains, building banks, levelling sloping land, and so on. Anything else was lumped together under biological methods for want of a better title.

This is appropriate for large mechanized farms where the approach is to use machines to do the earth-moving and follow up with improved farming methods. But this division does not suit the concept of erosion control through better land husbandry supported by mechanical protection, and the division is artificial when we start talking about progressive terracing using grass strips or live hedges.

An approach more suited to today’s thinking is to group methods and techniques according to their main objective. All have an element of saving soil loss, but an important difference is the handling of surface runoff. This chapter identifies three kinds of water management objective and two types of soil management on sloping land.

5.1 Introduction
Since the early days of human interaction with the environment, particularly in industrial settings, humans have continually been “shaped” to meet the demands of their surroundings. Historically, people have often endured significant discomfort and limitations without much complaint. In metaphorical terms, individuals have adapted by extending their reach to operate controls that were difficult to access, pushing their perceptual abilities to detect faint sounds or invisible signals, and compressing their bodies to fit into cramped workspaces. Cognitive abilities have also been stretched to accommodate monotonous or tedious tasks. However, as both work environments and machines have grown more complex, these challenges have become increasingly significant. A poor “fit” between the human operator and their environment has led to countless accidents, decreased productivity, and errors in many industries. The primary goal of ergonomics is to assess human capabilities and design the environment to align with these capabilities. Instead of attempting to adapt humans to jobs, ergonomics strives to “fit the job to the person.” This approach aims to optimize safety, efficiency, and comfort by aligning machine requirements with the operator’s abilities. By establishing a connection between humans and machines, ergonomics ensures that machines communicate information to the operator through their sensory systems, prompting a response that may alter the machine’s state. Key environmental factors such as temperature, humidity, lighting, sound, and visual conditions have a direct impact on both human well-being and the quality of production. The design of both the human workspace and the equipment used can be highly effective if the environment is conducive to the operator’s needs. Therefore, it is essential to study each environmental factor from an ergonomic perspective to ensure a comfortable and productive environment for workers. This includes designing jobs, equipment, and considering human anthropometric measurements in the design process.
5.2 Heat
Heat stress occurs as a result of the combined effects of environmental conditions, physical exertion, and clothing. The key environmental factors influencing heat stress include air temperature, humidity, radiant heat, and air movement, all of which can significantly affect work performance. Heat strain refers to the

Three fundamental processes that are responsible for inducing changes in weather are transfer of heat, energy and mass. The Sun, whose inter-surface temperature is estimated to be around 6000°C emits heat energy in the form of solar radiation which is received at the earth’s surface after it is partly depleted in the atmosphere. Therefore, it is essential to understand the processes that govern the transfer of heat in the earth-atmosphere system.

3.1 Conduction

The transfer of heat from one point to another point within the material medium without the actual movement of the particles in the medium is called conduction i.e. the heat energy transfer is conducted by the particles in the medium from hot end to cold end. If a metal rod is heated at one end, the other end of rod becomes hot gradually due to transfer of heat by conduction. In the earth atmosphere system, conduction of heat is observed at the ground surface only. The amount of heat energy transferred due to conduction (Q) is

2.1. Soil structure

Important physical properties of soils

Soil texture

Soil structure

Surface area

Soil density

The major components of soil consisting with mineral and organic matter, water and air produces a three phase systems of solid, liquid and gas. Many of the soil properties influencing crop growth and other uses depend mostly on the relative proportions of these components as well as the size, shape and arrangements of the solid matters. The physical properties of soil have strong significance in sustaining agricultural productivity. Fertiliser alone or in conjunction with suitable crop varieties and plant protection measures cannot be sufficient towards improving crop productivity unless the soil physical properties are maintained at satisfactory level. Improvement and restoration of physical properties in soil are necessary for protection of soil resources against degradation. The physical properties of soil discussed in this chapter includes soil densities, texture, structure, porosity and consistency of soils and colour of the soil.

Introduction

India is having very rich sources of inland water bodies in the form of river, lakes and reservoirs. The reservoirs are constructed by impounding the river system. The reservoirs are constructed for effective utilisation of water for irrigation, power generation and flood control. Reservoir fishery in India is also important from socio-economic point of view as it has the potential of providing employment to about two million people, Kaushal and Sharma (2001). Total area under the reservoirs in India is 3:1 million ha and it is expected to double by 2020. This includes 19,000 small reservoirs with a total water surface area of 14,85,557 ha and about 180 medium and 56 large reservoirs of 5,27,541 and 11,40, 268 ha area respectively.

The Maharashtra is endowed with an area of 1,79,430 ha under reservoir and the Maharashtra produces 516 tonnes of fish through reservoirs. The state fisheries corporation was operating in 6,272 ha of reservoirs and marketing the catches.

Soil texture and mechanical analysis: The chemistry of the mineral framework was explained in Chapter II. Its physical properties are quite as important- When all the extraneous matter is removed from the soil we are left with a collection of particles of various sizes. These particles are not spherical in shape, but most of them are nearly so. At any rate the discussion is very much simplified if we suppose that they are spherical and the arguments advanced are equally applicable if the shape deviates from the spherical.

Introduction

Drought is the most important abiotic factor that adversely affect growth and crop production. Drought stress can altered the normal physiological processes that influence one or a combination of biological factors for yield and yield attributing traits (Ashraf, 2010). The abnormal metabolism due to stress may reduce plant growth (Claves et al., 2002). Production is limited by environmental stresses, according to different scholar estimates, only 10 per cent of the world’s arable land is free from stress, in general, a major factor in the difference between yield and potential performance, environmental stresses. Drought is one of the most common environmental stresses that almost 25 per cent of agricultural lands for agricultural farm products in the world are limited (Loresto, 1976; Chaves, 2002). Drought occurrence in India is also very frequent. Drought occurred in past 1967, 1968, 1969, 1972, 1974, 1979, 1987, 2002, 2009 and had considerable impact on food grain production. For example, the drought of 1966-67 reduced overall food grains production by 19%. The drought of 1972-73 reduced the food grains production from 108.95 million tonnes to 95 million tonnes, causing a loss of about $ 400 million $. The 1987 drought in India damaged 58.6 million ha of cropped area affecting 285 million people (Ray et al., 2015). Drought in 2002 has reduced food grains production to 174 million tonnes from 212 million tonnes resulting in decline of 3.2% GDP (Rathore et al., 2009; Ray et al., 2015).

The water deficit reduces crop yield due to decrease in photosynthetic area, decreased radiation use efficiency and harvest index (Earl and Davis, 2003). Drought stress affect the water balance and plant metabolisms. Plants under drought conditions use various changes to tolerate stress conditions and increase drought tolerance which includes changes in whole plant, tissue, at physiological and molecular levels. Appearance of a single or a combination of inherent changes determines the ability of the plant to stand under aridity conditions. Tolerant plant adjusts its water balance by osmotic adjustment, deep root systems and by transient leaf rolling.

The seed yield, along with the rate of application and uptake of nutrients, is used to determine the following parameters for nitrogen or other nutrients:

Partial Factor Productivity (PFP) (kg seed/kg N applied): Partial Factor Productivity (PFP) is a measure used in agriculture to assess the efficiency of nutrient use, particularly nitrogen or other essential nutrients, in crop production. It is calculated as the ratio of the seed yield to the rate of nutrient application. The formula for PFP is:

*A higher PFP value indicates greater efficiency, meaning that more crop yield is produced per unit of nutrient applied. This is desirable as it implies that the nutrient is being used more effectively by the crop.

Agronomic Efficiency (AE) (kg seed/kg N applied): Agronomic Efficiency is a measure used to evaluate the effectiveness of nutrient application in increasing crop yield. It specifically assesses the yield gain per unit of nutrient applied. The formula for AE is:

Plants are frequently subjected to environmental stresses such as water deficit, freezing, heat and salt stress. Soil salinity is a major problem in arid and semi- arid regions, where rainfall is insufficient to leach salt and excess of sodium ion down and out of root zone. In Asia, around 21.5 million ha of cultivable land was affected by salinity. India had 8.6 million ha of salinity affected cultivable land. It is observed that the area of salinity has been increasing in India. In Tamil Nadu, the area affected by salinity is around 6 lakh ha. Salinity affected areas are Chengalpattu, Salem, Thanjavur, Trichy, Tirunelveli, Dharmapuri and Ramanathapuram. Salinity is the most serious threats to the agriculture especially in the arid and semi-arid region. The presence of salts in the soil and their effects on the plant physiological mechanisms was major restrictive factor for agricultural productivity. Investigations on such soils have revealed that they were charged with high and abnormal soluble salt concentrations that lowered agricultural yield, limited crop distribution and even lead to extinction of certain species.

Salinity adversely affects plant growth and development, hindering seed germination, seedling growth, enzyme activity, DNA, RNA, protein synthesis and mitosis. There has been a variation in the response of plants to salinity with its growth stages according to quantity and period of exposure to salt. Salinity by competing in nutrition element absorption causes growth reduction. Primary salt injuries include metabolic disturbance and inhibition of growth and development. Secondary salt effects include nutrient deficiency and osmotic dehydration. Excessive amounts of salts, especially sodium chloride (NaCl), in the soil induce osmotic effects, leading to changes in plant metabolism. General symptoms of damage by salt stress are growth inhibition, accelerated development and senescence and death during prolonged exposure. Salt stress causes the reduction of rice yield and severe salt stress may even threaten survival.

Abstract

Nitrate uptake from the soil is the first step in nitrate acquisition and utilization by plants. Nitrate uptake and its release into cells is mediated by nitrate transporter(s) located into the plasma membrane of the root. Three transporters have been identified by kinetic measurements in plant roots. These are constitutive high affinity nitrate transporter (cHATS), inducible high affinity nitrate transporter (iHATS) and low affinity nitrate transporter (LATS). Two of these display saturable kinetics; a low capacity constitutive system and a high capacity inducible system. In addition, a non-saturating low affinity, high capacity system becomes apparent only at higher external NO^-₃ concentration. Genes that encode representatives of each class of transport system have been identified and fall into two families: NRT1 and NRT2. Members of these families are induced in response to nitrate in the environment and are regulated by internal signals including nitrogen metabolites and shoot demand for nitrogen. This chapter deals with the physiology and molecular biology of nitrate transporters in higher plants.

Through green revolution, we have developed high yielding varieties albeit with high nutrient requirements putting much more reliance on chemical fertilizers. The major challenge facing plant biology right now is to improve crop production and to feed an expanding world population. This is against a background of pressure on agricultural land use and climate change having negative impacts on growing conditions. The adverse effects of agriculture, and specifically fertilizer use, include damage to the environment, a large carbon footprint for the manufacture and use of agrochemicals, and the utilization of non-renewable resources. One solution is to increase the area of land for agriculture, as well as increasing production while maintaining the current rate of inputs; however, this is predicted to have substantial negative impacts on the environment (Tilman et al., 2002), is unsustainable in terms of phosphate use, and would have a huge economic footprint in terms of energy demands for nitrogenous fertilizer production. The challenge is to increase yield, decrease inputs, and improve resistance to abiotic and biotic stresses. Improving crop nutrient use efficiency ideally requires an understanding of the whole system, from the macro (agro-ecosystem) to the molecular level.

4.1. Physiological disorders in field crops

Identification of physiological disorders in agricultural crops

Introduction

The physiological disorder of a mineral nutrient is entirely contingent upon its function within the plant body. Inadequate or excessive supply of any essential element can result in metabolic disruptions, influencing the activities of enzymes, rates of metabolic reactions, and concentrations of metabolites. Alongside alterations in metabolic patterns, severe deficiencies of specific essential elements also give rise to distinctive effects in leaves, stems, roots, blossoms, and fruits.

A. Nitrogen

Functions: Nitrogen is essential for plants, playing crucial roles in protein synthesis, nucleic acid formation, and chlorophyll synthesis. It is a key component of enzymes, contributing to various metabolic processes. Nitrogen also supports root development, cell structure, and the synthesis of secondary metabolites. Striking a balance in nitrogen levels is vital for maintaining plant health and ensuring optimal growth and productivity. Effective nitrogen management is essential for sustainable agriculture and overall ecosystem well-being.

Stress is force per unit area. When matter is subjected to stress; it may undergo changes in size, shape and displacement. Plants are grown in open environment and are likely to experience stress due to environmental conditions or when subjected to pests and diseases. The stress experienced by plants due to environmental conditions is called abiotic stresses. These include stresses caused by weather factors and climatic conditions and include moisture stress and thermal stress. The plants may also experience stress due to strong winds, dryness and as well as humid conditions (Fig.8.1).
The plants are generally classified into three types depending upon the ability to cope up with moisture stress as exhibited by-
• Drought resistance
• Drought tolerance
• Drought adaptations
The moisture stress may be to shortage of Water Compared to its requirements for evapotranspiration and metabolic activities. The plants may also suffer moisture