eChapters

10.1 Introduction

Biochemical Oxygen Demand (BOD) is a chemical procedure for determining how fast biological organisms use up oxygen in a body of water. It is usually performed over a 5 day period at 20 C. It is used in water quality management and assessment, ecology and environmental science. BOD is not an accurate quantitative test, although it could be considered as an indication of the quality of a water source.

10.2 Typical BOD values

Most pristine rivers will have a 5-day BOD of less than 1 mg/l. Moderately polluted rivers may have a BOD value in the range of 2 to 8 mg/l. Municipal sewage that is efficiently treated by a three stage process would have a value of about 20 mg/l. Untreated sewage varies, but averages around 600 mg/l in India and as low as 200 mg/l in the U.S., or where there is severe groundwater or surface water infiltration. Slurry from dairy farms is around 8000 mg/l and silage liquor around 60000 mg/l.

5.1 Introduction

The water quality modeling methodologies are started from conceptual models such as defining the problem in a particular region of interest like fresh water ecosystem, coastal ecosystems, ocean ecosystems, the following methodology can be studied carefully for water quality modeling.

Identification of problems in the region of interest

Monitoring of field data using standard methods like APHA, USGS, BIS etc.

Evaluation of primary data for the toxins, higher amount of concentration from the ambient conditions

Processing of primary data to secondary data

Based on the primary data and secondary data, suitable modeling software can be used. If the temperature of the region is higher than the ambient, it should be used Qual2E, MIKE21 etc.

Modeling results can be compared with field data for calibration and validation.

9.1. Introduction

Oceans (from Okeanos in Greek) are saline waters that cover almost three quarters (71%) of the surface of the Earth. The area of the oceans is 361 million sq. km., and nearly half of the world’s marine waters are over 3,000 meters deep.

Though somewhat arbitrarily divided into several “separate” oceans, these oceans are in fact one global, interconnected body of salt water, often called the World Ocean. The major divisions are defined in part by the continents and a variety of archipelagos, and are labeled the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Southern Ocean, and the Arctic Ocean. Smaller regions of the oceans are called seas, gulfs and straits.

There are a some smaller bodies of salt water that are not interconnected with the World Ocean. These are not considered to be oceans or parts of oceans, though some of them have been given the name, sea.

Geologically, an ocean is an area of oceanic crust covered by water. Oceanic crust is the thin layer of solidified volcanic basalt that covers the Earth’s mantle where there are no continents. From this point of view, there are three “oceans” today: the World Ocean, and the Black and Caspian Seas that were formed by the collision of Cimmeria with Laurasia. The Mediterranean Sea is very nearly its own “ocean”, being connected to the World Ocean through the Strait of Gibraltar, and indeed several times over the last few million years movement of the African Continent has closed the strait off entirely, making the Mediterranean a fourth “ocean”.

3.1 Introduction

By the end of the twentieth century one of our most important scientific accomplishments has been the explicit realization that the human population is changing the earth system. Some of these changes are occurring at a remarkable rate. We know, with certainty, that human activities are changing land use, habitats, the chemistry of the Earth’s atmosphere and water, rates and balance of biogeochemical processes, and diversity of life on the planet (Vitousek et al. 1997). One prominent mode of human disturbance has resulted from activities that mobilize the nutrient elements nitrogen and phosphorus through land clearing, production and applications of fertilizer, discharge of human waste, animal production, and combustion of fossil fuels (Nixon 1995).

As a result of these activities, surface waters and ground waters throughout the world now have elevated concentrations of N and P compared to concentrations even in the middle of the 20th century. Our mobilization of N and P has accelerated the fluxes of these elements to coastal waters, and fertilization of coastal ecosystems is now a serious environmental problem because it stimulates plant growth and disrupts the balance between the production and metabolism of organic matter in the coastal zone. Coastal eutrophication is a recently recognized phenomenon (Nixon 1995), and scientific investigation of this human disturbance has progressed for only a few decades, so our conceptual model of the problem is evolving rapidly. Here, I describe 2 phases in the evolution of our conceptual model of how nutrient enrichment disrupts coastal ecosystems, and then finish with a view to the future, suggesting critical questions that must be answered as we work to advance and broaden our understanding of this complex environmental problem. This examination of conceptual models is designed as a complement to the excellent general reviews of coastal eutrophication (Vollenweider 1992, Heip 1995, Nixon 1995, Jørgensen & Richardson 1996, National Research Council 2000).

6.1. Introduction

A river is a large natural waterway. The source of a river may be a lake, a spring, or a collection of small streams, known as headwaters. From their source, all rivers flow downhill, typically terminating in the ocean. The mouth, or lower end, of a river is known as its base level.

A river water is confined to a channel, made up of a stream bed between banks. Most rainfall on land passes through a river on its way to the ocean. Smaller side streams that join a river are tributaries. The scientific term for any flowing natural waterway is a stream; so in technical language, the term river is just a shorthand way to refer to a large stream. Rivers throughout history have been the source and support for civilization, and many major cities today are near a river of some sort (Fig. 6.1).

6.1.1 Topography

A river conducts water by constantly flowing from a higher to a lower elevation, thereby converting the potential energy of the water into kinetic energy. It starts to form loops and snakes through the plain by eroding the river banks. Sometimes the river will cut off a loop, shortening the channel and forming an oxbow lake from the cut off section. Rivers that carry large amounts of sediment may develop conspicuous deltas at their mouths, if conditions permit. Rivers, whose mouths are in saline tidal waters, may form estuaries. River mouths may also be rias.

1. Introduction
Water is the most crucial input for agricultural production. Globally, more than 80% of all freshwater used by humans are consumed in agriculture and most of it are for crop production (Morison et al., 2008). Currently about 60% of production in developing countries is derived from rainfall. Though irrigation provides only 10% of agricultural water use and covers just around 20% of the cropland, it can contribute about 40% of total food production since productivity of irrigated land is almost three times higher than that of rainfed land. The Food and Agriculture Organization (FAO) has predicted a net expansion of irrigated land of about 45 million is hectares in 93 developing countries (for a total of 242 million hectares in 2030). It projected that water withdrawals by the agriculture sector will increase by about 14% during 2000 – 2030 to meet the growing food demands (FAO, 2006). It is estimated that by 2050 in India, about 22 % of the geographic area and 17 % of the population will be under absolute water scarcity. The per capita availability of water which was about 1704 cubic meter in 2010 is projected to be 1235 cubic meter in 2050 (Anonymous, 2011). Infrastructure to increase the command area and minimize the gap of irrigation potential created and utilized is the dominant component of overall investment in agriculture (Anonymous, 2011). Besides this, judicious agricultural water management assists in ensuring good returns through efficient use of fertilizers and high yielding crop varieties. Above all, water will remain as a critical input for attaining sustainability in agricultural production. India’s current water supply is approximately 740 billion m3, which necessitates implementation of judicious water management technologies to enhance crop water productivity. In recent decades the world’s population has shown tremendous growth from an estimated 2.5 billion in the 1950’s to approximately 6.7 billion till date. It is expected that reduction in the average size of land holding, declining per capita water availability, deterioration of water quality etc. will seriously affect the sustainable use of water resources and will make it difficult to accomplish the target of producing 345 Mt of food grain in 2030 and 494 Mt in 2050 AD. To achieve the targeted food production, increase in the crop productivity from the present 2.3 to 4.0 t ha-1 under irrigated conditions and from 1.0 t ha-1 to 1.5 t ha-1 in rainfed area, productivity need to be increased at individual field level. This demands efficient use of water in agriculture, which can be achieved by reducing the losses of water and increasing the water uptake by the crops and it requires quantification of different water budgeting parameters like evapotranspiration and deep percolation.

Abiotic Stress Tolerance: The ability of plants to withstand and adapt to nonliving environmental stressors, such as drought, salinity, or extreme temperatures. Afforestation and Reforestation: Afforestation involves planting new forests in previously non-forested areas, while reforestation involves restoring degraded or deforested lands with trees to sequester carbon. Agrarian Society: A society characterized by agriculture as the primary means of subsistence and economic activity. Agrarian: Pertaining to the cultivation of land, agriculture, or rural life. Agribusiness: The commercial activities, including production, processing, and distribution, related to agriculture and farming. Agricultural Chemistry: A branch of chemistry that focuses on chemical processes and substances related to agriculture, including soil chemistry, fertilizer composition, and pesticide development. Agricultural Diversification: The strategy of expanding the range of crops, livestock, or other agricultural activities in a rural area to increase income and food security. Agricultural Economics: A branch of economics that focuses on the production, distribution, and consumption of agricultural goods and services, as well as the economic factors and policies that influence agricultural markets. Agricultural Extension: The application of scientific research and new technologies to agricultural practices through education and advisory services. Agricultural Innovation: The process of developing and adopting new ideas, practices, and technologies in agriculture. Agricultural Machinery: Various mechanical devices and equipment designed for use in farming, such as tractors, plows, and harvesters. Agricultural Subsidies: Financial incentives provided by governments to farmers or agricultural producers to support their production, stabilize prices, or achieve other economic or social objectives. Agriculture: The science and practice of cultivating crops, raising livestock, and managing resources for food production and other agricultural products. Agroecology: The scientific discipline that applies ecological principles to the design and management of sustainable agricultural systems, focusing on biodiversity, nutrient cycling, and reduced environmental impact.

Soil fertility evaluation is conducted for providing an adequate supply of essential plant nutriens to ensure optimum plant productivity, while maximising economic benefits and minimising environmental degradation.
 
Mathematical modelling of nutrient application

The significance of an essential plant nutrient was contained in the Liebig’s law of minimum.

Introduction

In view of the accepted importance of analysis, the workload on soil, plant and water testing laboratories has increased considerably in recent years. Therefore, analytical methods have needed to be accelerated through the automation of instruments. Almost all instruments either contain inbuilt computers or can interface directly with micro processors, thereby simplifying instrument operation and providing versatility for the analyst. Most operations can be performed through keyboard commands. This type of instrument automation enables:

India is an agricultural country. The geographical area of India is about 328 mha out of which 147 mha of land under cultivation and 84-mha land is under irrigation. The population is increasing at an alarming rate that requires producing more food for the growing population. This problem can be solved either by increasing the land under irrigation or using different soil water conservation techniques. It is well known fact that during rainfall a considerable amount of water goes to sea due to high rate of runoff. It is highly needed to trap as much as water falling in the form of rainfall and recharge the groundwater so that it is made available for irrigation purposes.

Moisture plays by far the most important role in soils as regards vegetation. It is through the medium of water that the plants obtain their quota of mineral food vital for their growth. If water is gradually withheld from the soil, at a certain stage, the plant will begin to wilt and soon dry up. The soil may still contain some moisture but the plant is unable to make use of it. The minimum moisture in the soil below which wilting will take place is called the Wilting Coefficient and at one time great importance was attached to it. The determination of this Coefficient, however, is tedius. One must grow a number of plants and slowly watch them wilt and determine the moisture content at that point. Moisture content of the soil is determined by heating a weighed quantity of the sample in an oven kept at 100-110 ^oC. The moisture is expressed as percentage on the oven-dry soil.

Abstract

Anantapur is the driest district of Andhra Pradesh and hence, agriculture conditions are very often precarious. Groundnut grows where other crops fail and thus it is the predominant crop of Anantapur district. Groundnut is grown in about 7.5 lakh ha in Anantapur district; however the average yields are low at 500 kg ha^-1. Among various available vegetation indices, normalised difference vegetation index (NDVI) is widely used for all reasons, which is a single numerical indicator of presence and condition of green vegetation. NDVI mapping at a regional scale helps to assess the spatial changes in the vigour of green vegetation and thus occurrence of any moisture stress. Climate tools have a great role in understanding the crop performance and estimating the yields. This study was taken up by using freely available MODIS data to understand NDVI in terms of abiotic stresses over Anantapur district and linking with the actual rainfall conditions, groundnut crop acreage and production. Results indicate that low groundnut yields in general could be related to NDVI-based stress measurements and rainfall quantum and distribution in the area however, with a few exceptions. It is hoped that by combining improved practices through IWM with climate-adapted crop varieties, rainfed farmers of Anantapur district can sustain their crop production under present climate variability and become resilient to future climate change.

Keywords: Climate, MODIS, NDVI, Anantapur, Groundnut, Integrated Watershed Management

Key words : GPS, GIS, DSS, SDSS, RS, Digital Elevation Model (DEM), Ground Water Exploration, Conjunctive Use of Surface and Ground Water, Digital Terrain Modeling (DTM).

Introduction

Water is one of the most precious gifts of nature to living beings and particularly to the mankind. On account of erratic distribution of rainfall both in time and space, the country is subjected to cycles of floods and droughts. With the increase in demand for water for various purposes and to mitigate the twin problems of floods and droughts faced by the country, a coordinated approach for optimum utilization and proper management of this precious resource is of prime importance. In addition, proper development and management of both irrigation and drainage systems are essential. This would require integrated management of surface water as well as gorund water. All the water related problems whether mitigating droughts or floods or better irrigation management practices, dictate for adoption of state of the art water management practices. Water management deals with the control, distribution and allocation of water flows and the treatment of rivers and catchments, consequently, solutions to many of the problems in water management require the knowledge and expertise from diverse sources.

Abstract

There is a consensus amongst the geoscientists that overall there has been progradation along the east and west coasts of peninsular India. However, the present day configuration of the coasts and some of the geomorphologic features such as absence of spit and delta along west coast and absence of major estuaries and petroliferous structures along east coast still remain controversial. The present study, based on the appreciation of certain geomorphological and tectonic features on Landsat imagery and aerial photographs of southern part of Indian Peninsula, suggests that the evolution of the coastline has been mainly controlled by tectonism.

The tapering nature of the coastline is attributed to the Precambrian orographic axis. The serrated nature of the post Precambrian coast line is due to the Precambrian transverse faults, whereas the serrated margin of the post Gondwana, Post cretaceous and post Tertiary coast lines are attributed once again to the Precambrian faults reactivated time and again. During the Quaternary period the coast line has undergone many modifications. The coast line attained sinuosity due to Pleistocene folding which is well manifested by river migration. The coast line was subsequently faulted and shifted with en echelon pattern due to N-S regional compression which is referable to the collision of Indian Plate with Tibetan plate.

Mosaic is the combination of two or more raster images into single image. Sometimes, single image captured by remote sensing satellite doesn’t completely covers the desired study area mostly. Therefore, users resort for mosaicking two or more images captured by satellite sensors from different paths so that the whole study area is merged into a single raster image to facilitate the image processing and analysis. The pixel size of the raster images should be same for mosaicking.

In most of the cases, there is spatial overlapping among the raster images from which we want to create mosaic. These overlapping areas are handled in multiple ways which is being discussed further using R – code example. For mosaicking raster images in R, mosaic function of the raster package is used.

The word mulch was coined by Wagganor in 1960. It is derived from the German word ‘molsch’ means “easy to decay,” and mulches have widely been used for vegetable production since ancient times (Lightfoot 1994). Therefore the term mulching refers to the practice of covering the soil surface with different organic and inorganic materials, known as mulch materials to reduce moisture loss, balance wide variations in diurnal soil temperatures especially in the root zone, control weeds, insect-pests and diseases and finally enhance crop yield (Nalayini 2007; Kader et al. 2019).

Introduction

The term multipurpose trees (MPT) refers to all woody perennials that are grown to provide more than one significant function (shelter shade, land sustainability) of the land use system they implement. More emphasis is given to trees which are indigenous in nature and have the capability to fix atmospheric nitrogen. All trees are said to be multipurpose. The term “multipurpose” as applied to trees for agroforestry refers to their use for more than one service or production function in an agroforestry system (Burley and Wood, 1991).

Multipurpose trees species (MPT) are grown to provide more than one significant crop of function or form. These may include fuel wood, fiber, fodder, flower, fruit, fertilizer (6F) timber, industrial purpose, nitrogen f ixing, soil conservation, soil protection and rehabilitation, shade and nurse trees, medicine, windbreak, shelterbelts, live fences, aesthetic or recreational purpose, shown in Table 16.1.

Trees are an integral and indispensable constituents of our natural surroundings. The trees keep the environment clean, make the soil healthy and provide food, fibre and shelter to mankind and wild animals. Trees help in stabilizing the soil, a vital natural resource, prevention of soil and water erosion, control run off water in the catchment areas, acts as a shelter belt against wind erosion in arid zone, act as a wind breaker to protect the coastal region during storm and cyclone besides contributing substantially to economic development. The National Commission on Agriculture stress the need for afforestation of about 40 million ha of land presently lying barren because of salinity, sodicity, waterloggings, ravines, coastal sandy areas, stony and gravelly lands, high altitude and slopping lands. Several agencies in various parts of the country are engaged in afforestation of these degraded lands.

Introduction

Time series data is data that has been collected in a specific pattern with time stamps. (Nayak and Ghosh, 2013). This type of time-oriented data is collected at regular intervals, such as hourly, daily, monthly, or weekly. Time series data can be used to make accurate predictions in a variety of fields and domains, such as foreign currency rates, stock market trends, energy consumption estimates, and climate change. Machine learning and data mining techniques can be used to uncover hidden patterns in historical data and forecast future trends (Aftab et al. 2018a, 2018b, Mishra et al. 2017).

Weather forecasting based on historical data is a complex but very beneficial task that comes with several issues that must be resolved to achieve optimal results (Wu and Chau, 2013). Weather data includes attributes or features such as temperature, pressure, humidity, and wind speed. Machine learning techniques are used to forecast future weather conditions by identifying hidden patterns and relationships in historical weather data (Aftab et al. 2018b). Prediction of precipitation is an important part of the weather forecasting process. The use of machine learning and artificial intelligence techniques is regarded as a critical component in farmer services and policy formulation. Farmers require weather forecasting to plan their activities following the predicted weather. Accurate and timely rainfall prediction in farming, in particular, can be extremely beneficial in planning and security measures for operations, agricultural tasks, water reservoir systems, and construction and transportation activities (Chau and Wu, 2010). Forecasting rainfall will become increasingly important in the future.

Mycorrhizal symbiosis is the most prevalent and important mutualistic association in plant kingdom. ‘Mycorrhiza’- the word means fungus - root, this association was reported by A.B.Frank in the year 1885. Nearly 95% of plant species form this mycorrhizal association. This serves as critical linkage between plant roots and soil and characterized by the movement of plant produced carbon to fungus and fungal acquired nutrients to plants. Through its hyphae this fungus absorbs the available P from soil and transports directly to root cortex. Mycorrhizal associations vary widely in structure and function. There are seven types of mycorrhizae (Table 1). These are endo (arbuscular), ecto, ectendo, arbutoid, monotropoid, ericoid, and orchidaceous mycorrhizae. Among them, endomycorrhizae and ectomycorrhizae are the most abundant and widespread