eChapters

ABIOTIC FACTORS: Environmental influences produced other than by living organisms for example, temperature, humidity, pH and other physical and chemical influences. Contrast it with ‘biotic factors’ - meaning effects due to biological components.

ACTIVATION ENERGY: The energy required before the reaction of concern will proceed. Often, heating will supply the needed energy. Enzymes or other catalysts lower the activation energy of a reaction.

AGRICULTURAL WASTE: The characteristics of the agricultural waste materials make them important in respect of their use and economic value. Agricultural wastes can he put to use because (1) Farm development (improvement of soil health, soil fertility, soil physical conditions and plant protection), it is the source of energy and power, (3) it acts as animal feed and fodder, (4) it is the human food

ACCELERATED EROSION: Erosion in excess of natural rates, usually as a result of anthropogenic activities.

ACID-FORMING FERTILIZER: A term applied to commercial fertilizers which leave an acid residue in the soil. The amount of calcium carbonate required to neutralize the acid residue is referred to its equivalent acidity.

ALLIC: soil family class term used in Oxisols as a calcareous and reaction class category. Soils placed in the allic class are acid and have low CEC with high amounts of KCl-extractable aluminum in a layer at least 30 cm thick within the control section. If used for agriculture, these Oxisols require large inputs of lime to displace the aluminum and raise pH.

This chapter presents laboratory procedures for measuring the major physical properties that regulate soil behaviour, water availability, aeration and root development. It begins with particle-density determination using a pycnometer and proceeds to bulk density, soil texture, moisture content, total pore space, porosity and water-holding capacity. Each practical exercise provides the underlying principle, required apparatus, procedural steps, calculations and relevant precautions. The hydrometer method is introduced for estimating the proportions of sand, silt and clay. Methods for evaluating moisture retention and pore relationships are also described. Collectively, these measurements help characterize soil structure, compaction, drainage, water storage and its suitability for crop production.

ABSORPTION ACTIVE: Movement of ions and water into the plant root as a result of metabolic processes by the root, frequently against an electrochemical potential gradient.

Life on Earth is rooted in soil. Soil is not just a substratum anchoring the plants and giving a base for all terrestrial animals. It is the largest terrestrial ecosystem, and one of the most wonderful ecosystems on Earth. It inhabits most microorganisms. Microbial populations flourishing within the soil have greater biomass than all the human beings, elephants, and whales put together. It is due to the microorganisms that the soil constitutes the most active ecosystem on Earth.

The health of the soil is crucial for the health of all the plants growing on it and for all the animals dependent on it for their inhabitation and nourishment. Soil health is also critical for the well-being of numerous microorganisms, detritivores, and several other organisms. Soil is composed of all essential nutrients/ minerals, air, water, and organisms in a proportion that strikes its ecological balance and maintains its structure and functions revealed through its productive potential.

Soil, like all other ecosystems, is itself a dynamic ecosystem. Its composition keeps changing but natural inbuilt mechanisms help strike a balance and recover 

Introduction
Historian “Donald Worster” tells us that fertilizers are not a replacement for rich soil. The soil is a resource for which there is no substitute. Time and climate have an impact on how soils develop as well. In humid and warm climates, soils develop more
quickly than in excessively dry or cold regions. In 15 years, under perfect temperature circumstances, soft parent material may develop into 1 centimeter of soil. It could take hundreds of years for a hard parent material to turn into soil in unfavorable climate conditions.
Definition
The land’s thin layer of soil is made up of a combination of minerals, organic matter, living things, air, and water that work together to support the growth of plants. The source material’s transformation into soil was influenced by a number of elements.
The accumulation of persistent poisonous compounds, chemicals, salts, radioactive elements, or disease-causing agents in soil that negatively impacts plant growth and animal health is known as soil pollution.

AERATION, SOIL: The exchange of air in soil with air from the atmosphere. The air in a well aerated soil is similar to that in the atmosphere; the air in a poorly aerated soil is considerably higher in carbon dioxide and lower in oxygen.

The plants draw water from the soil for growth and development. The soil acts a reservoir for soil moisture (Fig.5.1). The basic aim of a soil water balance model is to quantify the manner in which the water supplied to the soil either through precipitation and irrigation is disposed off. In the process, the soil water balance models were found to be extremely useful to determine the amount of water utilized by the crop for evapotranspiration.
The concept of water balance was originally developed by Thornthwaite, an American geographer and it formed the basis for development of more scientifi c advances due to its wide range of applicability including
• Choice of crops/ cropping systems based on water availability
• Irrigation scheduling
• Optimisation of limited water resources for higher productivity
• Characterization of droughts and agricultural droughts
• Assessment of crop yield and pre harvest forecasting of crop yields
• Designing irrigation projects
• Development of water storage structures
There are quite a large number of water balance models available in literature nowadays. Several of these models may be applicable for regions where there are developed. There were considerable efforts to develop water balance models can be used by the crop on daily basis in case of different crops as well. The choice of a water balance model to a large extent depends on the availability of data required for running the model. It may not be possible to cover all models available in

The soil consists of many solid particles of different sizes and is capable of absorbing and retaining water in the soil within certain limits when water is received through either from precipitation or by irrigation. The water that is held in the soil is called soil water (Fig.4.1). It can exist also in the form of water vapour as well. The crop production depends upon the soil water. All the water that is present in the soil may not be available for plants.
The water availability to the plants from the soil depends upon some physical properties of the soil as well as on the physical processes that govern the existence of water in the soil. Therefore, it is necessary to understand about the relationships that govern the water availability in the soil as explained in the following text-
4.1. Energy Concept of Soil Water
Soil water energy concept is all about potential energy, gravitational potential, osmatic potential, pressure potential energies.
4.1.1. Soil Water Energy: The total energy state of soil water is defined by its
equivalent potential energy as determined by various forces acting on the water per unit quantity. Different energies are involved including kinetic and potential energy.

Overview
Humanity has produced trash since the beginning of time, whether it is from the bones and other parts of the animals they kill for food or the wood they harvest to build their carts. As civilization developed, garbage was produced that was increasingly sophisticated in character. The world of consumers emerged around the close of the 19thcentury as a result of the industrial revolution. The production of non-biodegradable solid waste led to an increase in pollution not just in the air but also on Earth itself. The rise in solid waste was also primarily caused by urbanization and population growth.
Definition of Solid Waste
Glass crockery containers, plastic containers, sludge, vehicle parts, and mounds of crop wastes are among the solid waste materials. These gather in public areas and hinder people’s regular activities.
Every family produces waste or rubbish on a daily basis. We usually toss away items that we no longer need or have any use for, which puts them in the garbage category. Depending on where it comes from, solid waste can take several forms. Understanding the proper ways to handle the trash produced has become crucial in today’s dirty world. One crucial technique for managing municipal solid waste is segregation. Representation provides a good understanding of segregation at source. Composting is a crucial waste management and treatment technique.

Solid wastes are all the wastes arising from human and animal activities, that are normally solid and that are discarded as useless or unwanted materials. It consists of the highly heterogeneous mass of discarded materials from the urban community as well as the more homogenous accumulation of agricultural, industrial and mining waste.

Introduction
Energy is necessary for people, ecosystems, and living things to function. The effects of energy generation and use on the  environmentdetermine life quality. Our main source of energy comes from the sun. Energy is used by humans for running transportation, producing industrial items, farming, and residential use.
Definitions
Energy is the ability to do tasks.
Resource: Anything we obtain from our surroundings in order to fulfill our needs and wants. A natural resource is any substance or energy that comes from the environment and is utilized by all living things, including humans. Examples of natural resources include air, water, soil, minerals, plants, and wildlife.

Abstract

The groundwater behaviour in hard rock aquifer systems has always remained enigmatic owing to the heterogeneity of the aquifer systems. This is the reason why there are a lot of failures in groundwater targeting and management in hard rock aquifer systems even after the employment of many modern technologies. For precise groundwater targeting in hard rock aquifer systems various parameters like lithology, the type and the degree of structural deformation, the degree of weathering, geomorphology, etc., will have to be analysed which involves spatial analysis of voluminous data. In the sphere of spatial modelling, GIS plays an important role. Hence, a newer study has been carried out in parts of Madurai, Dindigul and Theni districts, Tamil Nadu, to identify the groundwater provinces and their functions using GIS. In the said study, GIS images were generated on the groundwater targets through GIS integration of transmissivity, permeability, storage co-efficient and water level. Such GIS image showing groundwater maxima was overlaid with GIS image of fracture maxima, subsurface geology maxima and the geomorphology maxima and thus by various GIS based spatial manipulations, aquifers controlled by structure, geomorphology, subsurface geology, and combinations of the above various variables were brought out. This has provided potential method for precise targeting of groundwater.

ABSTRACT

The estimation of the water requirement of crop is one of the basic needs for crop planning on the farm and for the planning of any irrigation project. Water requirements of crops include the losses due to Evapotranspiration (ET) plus the losses during the application of irrigation water (unavailable losses) and the quantity of water required for special operations such as transplanting and leaching of excess salts for crop growth. It is therefore necessary to estimate the ET and Crop Water Requirement (CWR) for the efficient use of water and increased crop production. In the present study, meteorological data were collected and the crop ET (ETc) and the CWR were estimated using FAO Penmann – Monteith method for the cropping pattern of the Buthangudy canal command area situated at a distance of 2Km from the popular village Sethiathope, Cuddalore district, of Tamil Nadu, India, which is located in between the Kumbhakonam – Chennai NH – 45 main road. The methodology combines the capability of GIS and CWR to produce maps showing spatial distribution of water resources over large areas.

Introduction

All spatial data stored in a GIS are associated with a map projection, either implicitly (so-called “unprojected” data stored with raw longitude, latitude coordinates) or explicitly (where the data have been transformed into a known map projection). Map projections are a particularly important feature of spatial data because they introduce error and distortion, since a sphere cannot be transformed to a plane without some stretching and twisting of the sphere’s surface.

The typical GIS package supports anywhere from 5 to 50 map projection types, and most projections may be modified or customized by varying their parameters. This flexibility is important for two reasons First, in order to use two or more layers together in a GIS for visualization or analysis, all data must be projected in the same way. Second, certain types of analyses, such as the measurement of area, are only valid when using certain types of projections (and conversely, are completely wrong when using an inappropriate projection).

Remote sensing images have an important characteristic known as spatial frequency. Spatial frequency is defined as the number of changes in pixel value per unit distance. Few changes in pixel or brightness value over an area in an image are known as low spatial frequency area like agricultural fields, forests, water bodies, etc. If the changes are large, then it is known as high frequency area like roads, built up areas, etc. Spatial filtering is an approach for extracting quantitative spatial information by taking into account the neighbouring pixel values along with the independent pixel value. Therefore, filtering is a technique for modifying or enhancing an image. Filtering is done to improve the interpretability of raster image or to extract certain information from them. It is a neighbourhood operation because the value of any pixel in the output image is determined by applying certain algorithm on the neighbourhood pixels of the corresponding input pixel. The nature of algorithm to be applied depends upon the information which user wants to derive from the raster image. Filtering operations are mainly done for smoothening, sharpening, noise removal and edge enhancement. A filter is a kernel of small array which is applied to input pixel and its neighbouring pixels in the raster. There are many types of filters which can be applied to a raster image in R. These types with their respective R – code examples are explained further.