eChapters

Water is the most important natural resource that governs and exercises control on living organisms on earth besides supporting all human activities. The demand for water is almost increasing at exponential rate due to increase in population and industrialization. All sectors of agriculture including crop production, horticulture, animal husbandry, poultry and fi sheries primarily depend upon water. Water scarcity can cause all kinds of miseries. The water exists in all 3 different forms on earth. It exists as snow or ice in glaciers and ice caps, liquid water in rivers, lakes, streams, tanks, ponds and as groundwater storage. The water exists in all three different forms in the atmosphere. The clouds may contain fi ne ice particles, tiny water droplets and as well as water vapour. The air in atmosphere also contains water vapour. It is estimated that 97% of water is salt water and remaining 3% of water is pure and fresh water. Approximately two-thirds of the fresh water is trapped in glaciers and ice caps. Most of the fresh water (30%) exists as groundwater. About 0.7% of fresh water exists as soil water and 0.3% a fresh water accounts for surface water resources and water present in the atmosphere as water vapour, water drops and ice particles. The circulation of water between oceans, earth and atmosphere forms hydrologic cycle.
2.1. Hydrological Cycle
The hydrological cycle explains the continuous recirculation and transport of water between the atmosphere, oceans and earth. It is a very complex system that has many sub cycles associated with it. For example, the water from earth surface, oceans and water bodies get evaporated due to heat energy received from the sun in the form of incident solar radiation (Fig.2.1).

Water is fundamental to life, supporting ecosystems, driving economies, and sustaining human well-being. However, the availability of this essential resource is increasingly threatened by hydrological drought, a complex phenomenon characterized by prolonged deficits in surface and subsurface water supplies. Unlike meteorological drought, which is defined by precipitation shortages, hydrological drought manifests as reduced stream flow, diminished lake and reservoir levels, and depleted groundwater, impacting water availability long after the rains have ceased. This chapter looks into the critical aspects of hydrological drought management, exploring the multifaceted nature of this challenge and outlining strategies to mitigate its devastating consequences. We will navigate the intricate web of factors that contribute to hydrological drought, from climatic drivers to the profound influence of human activities. Understanding these causes is paramount to developing effective management approaches.

Groundwater exists at many places beneath the surface of the earth. It is normally hidden from view but, on occasion, can be seen flowing from springs and wells or seeping into tunnels. Certain properties of the various geologic materials control the ability of groundwater to enter into, move through, be stored in, or be extracted from the ground. Therefore, an understanding of geology is necessary in order to gain an understanding of groundwater found within a particular area of investigation. A basic part of the study of the geology of an area includes the preparation of a map showing surfacial exposures of each rock type. Interpretation of the map facilitates the study of the underground configuration, characteristics, and physical properties of these materials. This, in turn, enables the evaluation of groundwater storage, movement, and yield, as well as the identification of areas of ground water quality problems, recharge, and extraction.

The fundamental unit of a geologic study is the geologic formation. A formation has been defined as any assemblage of rocks, which have some character in common, whether of origin, age, or composition. In this sense, the term “rock” is defined as any naturally occurring part of the earth’s crust, made up of aggregate of minerals and includes hard, dense granite, lava ash, clay, sand, and even loose-uncohesive soil.

Q. 1 The Lysimeter is used to determine
(A) Sun shine hours   (B) Wind velocity
(C) Flow velocity        (D) Evapotranspiration

Technical Term                        Definition

Hydrology                               Hydrology is the science of water derived from Greek wordî hydro + logosî i.e., water + sciences and hance defined as the science which deals with occurrence, distribution and circulation of atmospheric water through unending Hydrologic cycle.

A disaster is sudden event that causes significant damage to the people, environment and the economy. Disasters are serious disruptions to the functioning of a community that exceed its capacity to cope up using its own resources. The disasters that result either due to excess water or severe water deficit are floods and droughts.
12.1. Floods
The flood is an overflowing of water onto land that is normally dry. Floods may occur due to
• Heavy rainfall
• Ocean waves
• Snow melting
The economic losses due to floods will be very high and nearly 68 per cent of the economic losses are attributed to floods only. During the year 2018, India suffered a loss of nearly 90,000 crores due to floods alone. There are several causes for occurrence of floods in India. The major causes are
• Severe cyclonic storms in coastal areas which produce continuous heavy rainfall for 3 to 4 days in succession
• Encroachment of flood plains with residential structures
• Inadequate strength of river banks when there is high flows of water in the rivers
• Unplanned growth of urban areas
• Silting of water storage structures due to increased soil erosion thereby decreasing the storage capacity of reservoirs
• Simultaneous flooding of rivers and tributaries due to excessive water flows

Etiology

Group 1 adenovirus. First reported in Pakistan in 1987, where it caused a devastating effect on broiler industry. It has spread to all continents.

5.1 Introduction

Hydroponics is a method of growing plants in a nutrient solution rather than in soil. Terrestrial plants may be grown with only their roots exposed to the nutritious liquid.

Traditionally, the soil supports the crop’s roots by helping them remain upright and ensuring the delivery of water and essential nutrients. In hydroponics farming, crops are supported by an inert medium such as perlite, gravel, or other substrates. Therefore, the nutrients are supplied by using various practices that bring mineral nutrient solutions to the crops. In the present situation there excessive use of chemical fertilizers, affecting fertility of soil is badly affected. The fertility of the soil is falling that affects the plants growth but in hydroponics, the plant remains unaffected. Plants grow faster than in soil. Produce better quality of plants and higher yields. It use less water. It is possible to use hydroponics on outdoor crops, but most of the hydroponics production is in greenhouse. Hydroponic farming system has the potential to reduce the problem associated with traditional crop production. Therefore, it could serve to be a turning point in feeding the global population. The greenhouse and its environment control system are the same whether plants are grown conventionally or with hydroponics. The difference comes from the support system and the method of supplying water and nutrients.

The hydroponic farming has been successfully demonstrated by the commercial growers for fast-growing crops such as tomatoes, cucumbers, spinaches, lettuce, radishes, strawberries, bens, spring onions, coriander, and ornamentals. Indeed, hydroponics technology enables a more precise control of micro climatic conditions. In this technique, the vigorous development of a root system is taking place, which enable the uptake of essential nutrients from nutrient solution for better crop yield. The initial investment in hydroponics farming is high and required constant energy input. Owing to this, hydroponics farming is recommended for growing high value crops in developed countries such as the United States, Canada, Europe and Japan.

Introduction

The Greek terms hydro, which means water and ponos, which means labor are the roots of the word hydroponics, which literally means water work. Maharana and Koul (2011) defined hydroponics as a technique of growing plants in soil less conditions with their roots immersed in a nutrient solution. According to Savaas (2017), hydroponics can be briefly defined as the cultivation of plants without soil. So, it is clear that in hydroponics, plants are grown without soil, and they get nutrients from nutrient solutions added to water.

Introduction

Instead of using soil, the unique technique of hydroponics grows plants in a nutrient-rich water solution. Using a tightly controlled environment, gardeners may optimise factors including sunlight, pH balance, and nutrient levels to maximise plant development in this agricultural approach. Hydroponics allows plants to grow more quickly and produce more by delivering nutrients straight to their roots. Water efficiency, less soil-borne disease risk, and the capacity to grow crops in non-arable or urban areas are just a few of the benefits of this technology. More and more people are turning to hydroponics as a means to grow their own food in a more regulated and efficient manner, all while reducing their impact on the environment.

Hydroponics is a subset of hydroculture and is a method of growing plants using mineralnutrient solutions, in water, without soil. Terrestrial plants may be grown withtheir roots in the mineralnutrient solution only or in an inert medium, suchas perlite, gravel,mineral wool, expanded claypebbles or coconut husk

The techniques on hydroponics are widely used in plant sciences to elucidate several problemson nutrition. Primarily, this has been not only used to evaluate deficiency symptoms of an essential element but also used to assess waters stress effects in crop plants. There has been a considerable controversy whether such responses paralled with field responses. Though these techniques have their limitations, it is certain that it has its relevance in identifying certain genotypes relatively tolerant to some stresses such as water, O₂ and nutrition. Without entering to such debatable issue, it can be said thatwherenecessity demands, such techniques would proveuseful in demonstration purposes and evaluation of macronutrient deficiencies in tomato and maize. Thegrowing of plants in nutrient solution is called as water culture or hydroponics. These experiments in nutrient solutions are carried out to study the mineral nutrient relation of plants. By elements required for plant growth, specific deficiency symptoms can be produced in water culture experiments. Thesuccess of these experiments of producing deficiency symptoms depends upon the use of homogenous biological material and purity of culture solution in respect of different plant nutrients. Hydroponics is a subset of soilless culture. Many types of soilless culture do not use the mineral nutrient solutions required for hydroponics.

Plants that are not traditionally grown in a climate would be possible to grow usinga controlled environment systemlike hydroponics. NASA has also looked to utilize hydroponics in the space program. Ray Wheeler, plant physiologist at Kennedy Space Center’s Space Life Science Lab, believes thathydroponics will create advances within space travel. He terms this as a bioregenerative life support system.

Every research in agriculture aims at developing a promising new technology or refines an age old technology that can help addressing the improvement in crop yield. This is a worldwide scenario to meet up with the food needs of the growing population and reducing agricultural land resources. Many traditions in the world are associated with vast knowledge of cultivating the food crops, vegetables, fruits etc using selected methods that are modified based on the needs, climatic conditions and the resources available in the place of settlements. Soil based agriculture is the most popular method of growing plants since soil is considered as the main source of nutrients and water required for the healthy growth of crops. Generally it includes 3 major steps, ploughing, sowing and harvesting.

Introduction
A sustainable and effective replacement for conventional soil-based farming, hydroponics technology signifies a paradigm shift in agricultural techniques. Instead of using soil to develop their plants, hydroponic systems submerge their roots in a nutrient-rich water solution or provide it to them on a constant basis. This technique allows for maximum nutrient uptake and faster development by giving plants all the vital elements they require for growth. Hydroponics has many different and extensive uses in horticulture. Leafy greens like lettuce, spinach, and kale as well as vine crops like tomatoes, cucumbers, and peppers are among the many crops that are grown there.
Furthermore, strawberries, herbs, and even decorative plants like flowers grow beautifully in hydroponic systems. One of the key advantages of hydroponics is its ability to maximize resource efficiency. By delivering nutrients directly to the plants’ roots, hydroponic systems minimize nutrient wastage and water consumption compared to traditional soil-based agriculture. Because of this, hydroponics is especially appropriate for areas with limited arable land or water resources. Hydroponics’ adaptability to climate and location is yet another important benefit. No matter the outside weather, hydroponic systems can be installed indoors, in greenhouses, or even in urban settings to allow for yearround growing. This enables farmers to raise crop yields, lengthen growing seasons, and maintain steady levels of quality and output all year round.

Agriculture nowadays is facing a complex problem. It’s the rate at which we are turning arable land into non-arable. To solve this problem, we cannot simply stop farming and wait for the Earth to return to its natural state. Hence, alternative farming methods have become increasingly popular in recent years. Hydroponics is one of these options that can help produce crops without soil and other resources needed for crops to grow.

2.1 Definitions

Hydroponics is the term for growing plants without soil and in a water-based solution, the roots may be physically supported by an inert medium such as perlite, gravel, or other substrates. While it can be used to grow all kinds of crops, hydroponics is particularly effective for growing leafy vegetables, herbs and salad greens that have high water requirements, as well as for growing plants that have very shallow root systems. 

Hydroponics is a technique of growing plants using mineral nutrient solutions with or without the use of an inert medium such as gravel, soil, vermiculite, rock wool, peat moss, saw dust, coir dust and coconut fibre-provide mechanical support. The term Hydroponics was derived from the Greek words ‘hydro’ means water and ‘ponos’ means labour and means water work. The word hydroponics was coined by Professor William Gericke in the early 1930s; describe the growing of plants with their roots suspended in water containing mineral nutrients. Researchers at Purdue University developed the nutriculture system in 1940. During 1960s and 70s, commercial hydroponics farms were developed in Arizona, Abu Dhabi, Belgium, California, Denmark, German, Holland, Iran, Italy, Japan, Russian Federation and other countries.

Safe, wholesome and nutritious food is vital for sustenance, good health, food and nutritional security and augmentation of sustainable development of an individual. Also, safe food helps in the growth of the national economy and enhances the trade and tourism sector. Foods that are unsafe containing various kinds of microorganisms can cause chronic diseases or illnesses varying from diarrhea to cancer.

Indicator bacteria are types of bacteria that are used to provide an indication of poor hygiene, inadequate processing and or post - process contamination in seafood, water, feed, ice, equipments, workers, etc. Absence of indicator bacteria in seafood and aquaculture products provides a degree of quality assurance that the fishery products are hygienically good and have employed proper processing methods whereas their presence clearly indicates either severe problem or failure occurred during the processing, under-processing or post-process contamination. The indicator bacteria in fish and fishery products are mainly from enterobacteriaceae and coliforms group of bacteria. Traditionally, indicator micro-organisms have been used to suggest the presence of pathogens (Berg, 1978) and it includes the general microbial Process indicators, Faecal indicators, and Index and Model indicator organisms. The Process indicator is a group of organisms that indicates the efficacy of a processing and tested by Total Plate count (TPC)/ Total heterophilic count or total coliforms (MPN method). Fecal indicator is a group of organisms that indicates the presence of fecal contamination and could be tested for fecal coliforms, thermotolerant coliforms (MPN method) and E.coli (EMB and IMViC test). Index and model organisms are a group of organisms that indicates the presence of pathogens such as E.coli are an index for Salmonella and coliphages as model of human enteric viruses. The pathogenic indicator bacteria viz., Coliforms, Fecal coliforms, E.coli, Klebsiella, Enterobacter, Citrobacter, Fecal Streptococci, Sulphite reducing clostridia, Clostridium perfringens, Bifidobacteria, Bacteriophages, coliphages and Bacteroides fragilis etc., are associated with food poisoning. In addition, pathogenic viruses, protozoa and parasites are also present in fecal matter. Fecal contamination is mainly from sewage of human source, livestock, poultry manure, pets and wildlife. Infection caused by these pathogens mainly depend on the level of microbial load.

Poultry hatchery is a place where the hatching egg is transformed into a one day old chick, during 21 days. The environment of a poultry hatchery is very susceptible to contamination by microorganisms which can adversely affect hatchability of the eggs and can result in embryonic deaths. E. coli, Staphylococcus species, Streptococcus species, Aspergillus fumigates and Pseudomonas species are mainly isolated from hatchery and it adversely affects chick quality and cause embryonic deaths. Poor standards of hatchery hygiene may lead ultimately to an explosion of pathogenic organisms resulting in severe economic loss.