eChapters

Q. 1 Froude number is the ratio between
(A) Inertia force to viscous forces (B) Inertia force to gravity force
(C) Inertia force to shear force      (D) Gravity force to inertia force

6.1 Introduction

Farm ponds used in farmers’ fields are generally square shaped or rectangular shaped pyramidal structures. It has a regular side slope, depth, and top and bottom dimensions. It may be excavated/dugout pond or embankment pond. In excavated pond, the pond is constructed below the ground level. Water is collected in the pond by gravity from the adjacent catchment. In embankment type, the pond is partly above the ground and partly below. This type of pond has higher storage capacity than the dugout type pond. This type of pond has a berm and dyke/embankment around the pond. The embankment has some side slope. The pond has bottom dimensions, dimensions at the ground level as well as some dimensions at the top above the embankment. In this chapter, various dimensions of pond like depth, side slope of the pond, as well as the various dimensions at bottom, ground and top level will be discussed.

Aim: Determination of percentage regulation and efficiency of a single phase transformer by direct loading method.

Percentage regulation

When the load on the transformer is increased, the voltage drop in its primary and secondary windings also increases causing variations in secondary terminal voltage. The term voltage regulation of transformer means the change in secondary terminal voltage when full load is thrown off keeping supply voltage and frequency constant. It is generally expressed as percentage of no load terminal voltage for a desired power factor.

Background and Technology Intervention

The primary resource affected by the climate change is water. In arid and semi-arid regions of India, any shortfall in water supply due to climate change will enhance competition for water use for a wide range of economic, social and environmental applications. The population growth with the improved living conditions also increases the demand for food production and thereby increasing the demand of water in multiple folds in the river basins (UNESCO-WWAP, 2009). The major portion of water available in the Indian River basins are used for cultivating rice and thus poses major challenges to water management, especially during unfavourable climatic conditions.

Introduction

Disaster may be defined as a sudden event that causes damage to life, property and destroy the economic, social and cultural life of people. It could be of natural or anthropogenic origin. Disasters impact the poor and the most vulnerable section of the community. Over the past 30 years, more than 2.5 million people and nearly $4 trillion have been lost to natural disasters in India; globally the losses jumped from $50 billion a year in the 1980s to $200 billion in the last decade (NIDM, 2019).According to a World Bank report, nearly 75% of the losses are attributable to extreme weather events and climate change threatening to push an additional 100 million people into the extreme poverty by 2030 (Hallegatte et al., 2016). The Bank’s Unbreakable report finds that natural disasters had larger and long-lasting impacts on the poverty. Population growth and rapid urbanization are major driving factors for an increase in the disaster risks.

The United Nations estimates that more than two-thirds of the world’s population will live in cities by 2050 (NIDM, 2019). This could put 1.3 billion people and $158 trillion assets at risk from river and coastal floods alone. According to the Bank’s Investing in Urban Resilience report (2016), by 2030, without significant investment into making cities more resilient, natural disasters may cost cities worldwide $314 billion each year.

4.1 Introduction

Discharge is also called as rate of flow. Discharge is defined as the volume of water flowing through a cross section in a unit time. It can be expressed as cubic metre per second (cumec), cubic feet per second (cusec), litre per sec (lps) etc. One cumec is equivalent to 35.5 cusecs or 1000 lps. The measurement of discharge is very important in everyday life starting from deciding the amount of irrigation to be supplied to a crop at a particular growth stage, or amount of water supply for domestic and industrial uses, for flood control and power generation etc. It plays a vital role in water resources planning. If a stage-discharge (also called as gauge-discharge) relationship for a particular gauging site is developed, then daily measurement of discharge in the gauging site is not required. Discharge can be estimated from the developed relationship of discharge versus stage if the measurement of stage is known.

3.1 Introduction

Irrigation water that is supplied to crop fields is defined by a term commonly called as discharge which is also called as rate of flow. Discharge is defined as the volume of water flowing through a cross section in a unit time. It can be expressed as cubic metre per second (cumec), cubic feet per second (cusec), litre per sec (lps) etc. one cumec is equivalent to 35.5 cusecs or 1000 lps. The measurement of discharge is very important in everyday life starting from deciding the amount of irrigation to be supplied to a crop at a particular growth stage, or amount of water supply for domestic and industrial uses, for flood control and power generation etc. It plays a vital role in water resources planning.

3.2 Methods of Discharge Measurement

The various methods of discharge measurement can be broadly classified into the following types: (i) volume method of discharge measurement (ii) flow measuring structures such as orifices, mouthpieces, flumes and weirs.

ABSTRACT

This work presents the results of multispectral analysis of TM (Thematic Mapper) sensor images on board the satellite LANDSAT 5 for discrimination of selected features of a Nainarmalai region of part of Namakkal District, Tamil Nadu using hyperspectral tools. The spectral classification was carried out using hyperspectral tools namely, a) spectral reduction by the Minimum Noise Fraction (MNF) transformation, b) spatial reduction by the Pixel Purity Index (PPI) and c) manual identification of the end members using the N-dimensional visualizer. The results of study shows that the kinds of features such as magnetite quartzite, sand, harvested land and vegetation area are discriminated well (as given in the figure) and show a strong correlation with landscape.

Keywords: Landsat TM Multispectral Images, MNF transformation, PPI, endmembers, Reflectance spectrum, ENVI software.

1. INTRODUCTION

With a multispectral analysis of an images collected by radiometers and detectors embarked on a satellite, one can make: “spectroscopy by satellite imagery”. Imaging spectrometers or “multispectral sensors” are remote sensing instruments that combine the spatial presentation of an imaging sensor with the analytical capabilities of a spectrometer. With a radiometer such as AVIRIS ”Airborne Visible/Infrared Imaging Spectrometer” where the number of spectral bands exceeds the 200, and with a spectral resolution of the order of 10 nm or narrow, it can produce a complete spectrum for each pixel of the image. The case of this radiometer enters on the “Hyperspectral” field. In the case of our study, we are using the radiometer TM (Thematic Mapper), which is on board for the satellite Landsat 5, and which only has 7 multispectral bands, with a spectral resolution of the order of 100 nm. Like finale result, one using the spectroscopy by satellite imagery, we can identify the spectra of various materials which are on various terrestrial surfaces.

Introduction

In agriculture, plant diseases have always been a major problem, as they cause crop quality to decrease, resulting in yield. Plant disease has a range of effects from minor symptoms to serious damages in whole crop areas, which lead to high financial costs and significantly impact the agricultural economy, particularly in developing countries dependent on a single crop or on a few crops.

Various approaches have been developed to detect disease in order to avoid significant losses. Causal agents have been precisely defined by methods developed in molecular biology and immunology. However, for many farmers these techniques are inaccessible and require detailed knowledge of the field or substantial time and energy to be used. According to the United Nations Food and Agriculture Organization, most farms in the world are small and family-owned in developed countries. Such families provide food for a significant proportion of the population of the planet. However, hunger and food insecurity are not rare and there is restricted access to markets and services. For the above reasons, a great deal of work has been undertaken in order to establish methods that are sufficiently reliable and available to most farmers. Where Plant disease is an essential factor contributing to a major decline in plant production quality and quantity. Plant disease identification and classification are a significant role in improving plant production and economic development.

10.1. Sugarcane

10.1.1. Yellow leaf disease

1. Vector: Melanaphis sacchari , Rhopalosiphum maidis

2. Symptoms

7.1. Rice

7.1.1. Blast

Magnaporthe oryzae (formerly Magnaporthe grisea) anamorph: (Pyricularia oryzae)

9.1. Groundnut

9.1.1. Early leaf spot: Cercospora arachidicola

1. Symptoms

8.1. Redgram

8.1.1. Wilt: Fusarium udum

1. Symptoms

Introduction 
As we have journeyed through the preceding chapters, meticulously examining the foundational understanding of crop-weather interactions, the sophisticated development of crop simulation models and decision support systems, the invaluable contributions of indigenous technical knowledge, and the systematic formulation of precise and customized agroadvisories, we now arrive at the decisive stage of this entire endeavor of dissemination of Agromet Advisories. The profound scientific insights and meticulously crafted recommendations, no matter how accurate or relevant, remain inert unless they effectively reach the hands, ears, or screens of the farmers who need them most, in a format they can readily understand and apply. This chapter, therefore, is dedicated to unraveling the complex, yet essential, process of ensuring that crucial agrometeorological information successfully traverses the last mile to translate into tangible impact on agricultural practices and outcomes across diverse landscapes. The challenge of effective dissemination extends far beyond a simple broadcast; it necessitates the establishment of a robust, dynamic, and multichannel communication ecosystem. This ecosystem must be meticulously designed to account for the rich tapestry of socio-economic, technological, and literacy disparities prevalent within farming communities. Historically, traditional methods such as the communal gathering around a radio for a farmer‘s bulletin or face-to-face discussions during village meetings formed the bedrock of knowledge transfer, leveraging established social networks and widely accessible, albeit low-tech, communication tools. However, the relentless march of the digital revolution has fundamentally reshaped this landscape, unveiling an unprecedented potential for expansive reach, enhanced personalization, and rapid delivery of information, thereby opening a myriad of new avenues for disseminating critical advisories with remarkable speed and specificity.

Dissolved oxygen (DO) refers to oxygen gas that is dissolved in water. Fish are able to absorb oxygen directly from the water into their bloodstream using gills. There are three main sources of oxygen in the aquatic environment: 1) direct diffusion from the atmosphere; 2) wind and wave action; and 3) photosynthesis. Oxygen depletion refers to low levels of DO and may result in fish mortality. A concentration of 5 mg/L DO is recommended for optimum fish health. Sensitivity to low levels of dissolved oxygen is species specific, however, most species of fish are distressed when DO falls to 2-4 mg/L. Mortality usually occurs at concentrations less than 2 mg/L. If fishes gulfing on the water surface and also show the low swimming in the water it indicates deficiency of dissolved oxygen in pond.

ABSTRACT

Presence of mangrove ecosystems on coastline, save lives and property during natural hazards such as cyclones, storm surges and erosion. This study is undertaken to assess the distribution of mangroves in Tamil Nadu. Geographical Information System, Remote Sensing and GPS (Global Positioning System) were used for mapping the mangrove forests. Mangrove wetland map and species zonation maps have been done using didital analysis of Remote Sensing data and ground truth information. The total area of mangroves found in Tamil Nadu and in Puducherry is around 4100ha.

1. INTRODUCTION

Mangroves are typical, tropical specialized trees growing in the saline and brackish water system. Mangrove plants live in muddy and wet saline soils. They are trees associated with shrubs, growing both on the sheltered coast and inland, lining the bank of estuaries and rivers. They are an ecological group of evergreen plant species, belonging to different families, but possessing marked similarities in their physiological characteristics and structural adaptations. Mangrove areas are associated with high leaf production and leaf fall and rapid decomposition of the litter.

Mangrove forests perform multiple ecological functions: They produce woody trees, provide habitat and detritus food for fish and shellfish and act as spawning ground for a variety of fishes, prawns and shellfishes. They harbour a variety of valuable fauna, including migratory birds. They also protect the coasts from storms and tidal waves and help in the formation of land by trapping sediments brought by the coastal community.There are many threats to mangroves. Deforestation is one of the major threats.

Introduction

There is different type of distributors available in the market. Depending on the basic principle of working they may be broadly classified into three major groups as below (FAO, 1980).

i. Distributors in which head loss takes place through small diameter tubes

ii. Distributors in which head loss takes place through some orifice control

iii. Distributors in which head loss takes place through a vortex action

There are many adaptations to distributors though the working distributors fall under the above stated basic principle. Tiny perforation in the laterals or porous materials allows leaking out the water serves the purpose of distributors. The compensating type distributors have long path in it to dissipate the energy and drips almost same rate within certain range of pressure variation. Whatever may be the distributors proposed to be used, the discharge characteristics should be known. The discharge characteristics should be provided by the manufacturers and preferably certified by any authorized body; otherwise to be tested by the designer before recommendation to large-scale use.

Introduction

Dough is a complex mixture of flour constituents, water, salt and other ingredients depending upon the requirements of end-products. It is the principal intermediate stage in the transformation of wheat into different end-use products. Rheological properties of dough determine the behaviour of dough during mixing, rounding and molding used in making different products and also effect on the quality of finished product. Therefore, understanding the various features of dough rheology and their relations with product quality is important. The importance is enhanced further because of mechanization and automation of baking industry. Dough is composed of continuous phase in which gas cells are dispersed. The continuous phase is called “dough phase”. It consists of starch granules embedded in protein matrix along with some lipids, cell remnants and yeast cells in fermented dough. Gas production and retention is the most comprehensive quality requirements of the dough for bread making. The ability of the wheat dough to retain gas during fermentation and oven rise is unique. This depends on the ability of the dough to be stretched into thin membranes because of protein phase.

1.1 R and R studio

R has become the world-wide language for statistics, predictive analytics, and data visualization. R is not limited to statistics; it has a wide range of tools for spatial analysis and digital image analysis and can handle any process needed for image analysis flexibly. It offers a wide range of methodologies for digital image processing, from the most basic to the most complex. As an open source project, it’s freely available for a range of platforms, including Windows, Mac OS X, and Linux. An integrated development environment (IDE) for R, R Studio, allows interactive execution of R functions with user interface. RStudio is available in two formats - RStudio Desktop and RStudio Server - both available in free and fee-based (commercial) editions.

1.1.1. Download and install R

The R software setup files can be downloaded from any of the widely distributed Comprehensive R Archive Network (CRAN). To download R, please choose your preferred CRAN mirror, a location close to you. Follow the following steps:

Agricultural land drainage is adopted for removal of excess surface and subsurface water, either from irrigation or rainfall in order to improve the profitability of land use.  Drainage also plays a role in removal of salts from the root zone. Therefore, land drainage is closely linked to irrigation in arid and semi arid regions. India has a long history of practicing irrigation and drainage in its semi arid irrigated regions. During the ancient times in the Indus Valley dams and drainage system were built for cultivation of different crops. The earlier experience of drainage was more concerned with surface drainage because from time immemorial India has been experiencing floods of varying magnitudes.