eChapters

The purpose of a sub-surface drainage system is to lower the ground water table and removal of salts beyond the crop root zone. The ground water beyond table may rise due to commonly practiced flood irrigation method, seepage from unlined channels, percolation of rain and runoff water and sub-surface flow from higher areas. Sub-surface drainage consists of drains laid at a specified depth, spacing and grade below the ground surface. The size, spacing and depth of drains depend largely on the soil-water properties viz., infiltration, saturated hydraulic conductivity, drainable porosity; and the requirement of removal of water through drains in certain time period fixed on the basis of rainfall and crop cultivated. The drains are usually placed in a pervious stratum. Suitable filter of coarse sand and gravel may be used when it is placed in a low permeable stratum. Sub-surface drainage serves the important job of removal of concentrated salt solution from the crop root zone particularly in arid and semiarid region.

Advantage of sub-surface drainage system

1. Since sub-surface drainage are underground, no loss of land for cultivation. Some part of the land goes out of use for making drains in surface drainage.

Raster sub-setting is done to select the desired area or bands of the raster image on which the user wants to perform analysis. Raster sub-setting is done in two ways:

Spectral subset: Spectral sub-setting is done to extract few desired bands from the multiband raster image which are required for analysis.

Spatial subset: Spatial sub-setting is done to minimize the area or extent of raster image to the desired area or extent for further analysis.

Raster sub-setting in R is done by functions available in the ‘raster’ package. The following packages are required in this chapter:

Sulfate can have harmful effects on aquatic life in freshwaters, sulfate cause osmotic stress or specific ion toxicity in aquatic organisms, especially in soft waters where Ca2+ and Mg2+ concentrations are low. Egg fertilization and early embryonic development were the most sensitive developmental stages of whitefish to sulfate (Karjalainen et al., 2021).
Sulphate (SO4 2-) may be estimated by either turbidimetric or gravimetric methods (APHA, 1995)
1. Turbidimetric method is more applicable in the range of 1- 40 mg Sulphate (SO4 2-)/ L
2. Gravimetric method is suitable if the concentration of Sulphate (SO4 2-) is above 10 mg/ L
Turbidimetric Method (Range 1 - 40 mg/L of sulphate) Principle
Sulphate ion (SO4 2-) precipitated with barium chloride (BaCl2) in an acetic acid medium in order to form crystals of barium sulphate (BaSO4).
BaCl2 + SO4 2-+ BaSO4 (precipitate)
The formation of these crystals is increased in the presence of an acetic acid solution containing sodium acetate, potassium nitrate, acetic acid and magnesium chloride. The suspended barium sulphate (BaSO4) is measured by spectrophotometer and concentration of sulphate (SO4 2-) is determined by comparison of the reading with a standard curve. Minimum detectable concentration is approximately 1 mg (SO4 2-) / L.

Microbial transformations of sulfur (S) are even more complex than those of nitrogen because of the large number of oxidation states of S and the fact that several transformations of S also occur abiotically. Although a number of oxidation states of S are possible, only three are significant in nature, 2 (sulfhydryl, R–SH, and sulfide, HS-), 0 (elemental sulfur, S0), and 6 (sulfate, SO₄ 2-). The bulk of S Earth’s S is in sediments and rocks in the form of sulfate minerals, primarily gypsum (CaSO₄) and sulfide minerals (pyrite, FeS2), but the oceans constitute the most significant reservoir of SO₄ ^2- in the biosphere. A significant amount of S, in particular sulfur dioxide (SO₂), enters the S cycle from human activities, primarily the burning of fossil fuels.

Hydrogen Sulfide and Sulfate Reduction

A major volatile S gas is hydrogen sulfide (H₂S). Hydrogen sulfide is produced from bacterial sulfate reduction or is emitted from sulfide springs and volcanoes. Although H₂S is volatile, different forms exist depending on pH: H₂S predominates below pH 7 and the nonvolatile HS- and S^2- predominate above pH 7. Collectively,H₂S, HS, and S₂ are referred to as “sulfide.” Sulfate-reducing bacteria are a large and highly diverse group and are widespread in nature. However, in anoxic habitats such as freshwater sediments and many soils, sulfate reduction is SO₄ ^2- limited. Moreover, because organic electron donors (or H₂, which is a product of the fermentation of organic compounds) are needed to support sulfate reduction, it only occurs where significant amounts of organic material are present.

Sulphur (S) occurs in soil in both organic and inorganic forms. Inorganic S fraction may occur as sulphate (SO₄^2-) and compounds of lower oxidation state such as sulphide (S^2-), polysulphide (S_n^2-), thiosulphate (S₂O₃^2-) and elemental sulphur (S⁰). In well drained soils inorganic S usually present as sulphate. Under anaerobic condition (reduced or waterlogged soil) inorganic S mainly occur as sulphide and under extreme condition as elemental S form. Estimation of S carried out in two steps:

Sulphur in nature follows similar cycle as that of nitrogen and shares many common features with it. In soils, decomposition of organic matter releases major portion of nitrogen and sulphur bound in proteins, as cystine or methionine amino acids, or vitamins, etc. In proteins, on an average, for every 36 atoms of nitrogen one atom of sulphur is present. Mineralization supplies a large fraction of nitrogen and sulphur to the plants. Secondly, both nitrogen and sulphur have several chemical forms under different soil conditions (Table 8.1) and both are subject to microbial reduction. Thirdly, both can enter or leave soil in gaseous form and both are subject to some degree of leaching in the anionic form.

Supervised classification is the technique to classify raster image in which prior information about the classes in the form of training sites is provided by the user. Training site represents a homogeneous area in a particular class. The spectral response pattern of training sites is used to classify the raster image.The pixels of raster imagewhich have spectral response pattern similar to that of training sites of a particular class are grouped in that class. As there is some variability in the spectral response pattern of a particular class, therefore, multiple training sites per class are taken for supervised classification. Supervised classification of raster images can be performed by various methods. Conventional methods include maximum likelihood classifier, minimum distance to mean classifier, and parallelepiped classifier. Now a days, machine learning algorithms are also gaining importance in this context. These classifying algorithms are first trained or calibrated using the data of training sites.This trained model is then validated on the independent datasets for accuracy assessment. If the accuracy of the developed model is of acceptable level, then that model is used for the classification of raster data.

In this chapter, we are going to discuss the execution of maximum likelihood classifier and few machine learning techniques for supervised classification of raster image in R software. The training sites used in this exercise are in the form of points shapefile. The raster image is classified into six classesi.e. built- up, fallow soil, riverine sand, salt-affected soil, vegetation, and water. For performing this exercise, first of all,set the working directory and import the required packages.

12.1 Introduction

Agricultural drainage is the removal of excess water from the farmland for the purpose of providing favorable soil air environment for plant growth. Removal of water may take place form the surface or below the surface of the land. The practice of lowering ground water table below the root zone depth to improve the plant growth or to reduce the accumulation of salts in soil is also called as drainage

Drainage system is broadly classified as surface & subsurface drainage. Removal of excess water over the land surface is known as surface drainage & that of removing water below the surface is known as subsurface drainage. The flow of water in the form of evaporation or evapotranspiration also play important role in improving drainage situation. It gives the idea of the time required to get the wetland workable though it is not called a type of drainage as because this is very slow process & cannot be controlled by the human activities. However, using of certain tree plants e.g., Eucalyptus, Poplar, Casurina or similar species in wet fields, which transpires at high rate and improves the drainage problem by lowering the shallow water table is the new idea known as bio-drainage.

Abstract

The state of Tamil Nadu has a low easterly gradient slope and there are number of rivers, big and small originate from the west flow towards east south easterly and confluence the Bay of Bengal. These were grouped into seventeen major and minor river basins, the Cauvery being the largest basin and the river is also a near perennial river. These river basins receive rainfall both from the southwest and northeast monsoons. The state has over 40,000 surface water bodies and number of major dams and reservoirs. Even then, since the rainfall of the north east monsoon, the major source of water source to these basins, occurs in short span of few days with high rainfall, neither adequate storage is there to store them nor the recharge possibility is available, thus all leading to flooding and wastage. The 40,000 and odd water bodies are heavily silted and polluted too. The paper provides an over view of all these, basin wise, and in addition, strongly advocates intra state river linkage and improvised irrigation management as the best option to save the state from its water deficiency.

5.1 INTRODUCTION: THE PHYSICAL CHEMISTRY OF COLLOIDAL SUSPENSIONS

This chapter is concerned with understanding the factors which influence the partition of ions between solid surfaces and aqueous solutions. There are many aspects of soil science such as some of those concerned with soil formation, transfer of nutrient ions from soil particles to plant roots, soil pollutant interaction and soil management which are critically dependent on what happens in the space of the order of 1 nm wide between solid and equilibrium solution. A broad survey of the development of ideas on soil-electrolyte interaction shows that there have been two main avenues of approach. One views the soil as an electrically charged surface with its adsorbed hydrated ions as one phase in equilibrium with solution, which is seen as the second phase. The other approach focuses on the electrical double layer extending from the charged solid surface out into the solution. In the latter approach the solid surface, the outer equilibrium solution and the make up of the transition zone between these two phases must all be involved in any detailed consideration of the micro structure of the system. For a full and proper understanding of soil-electrolyte interaction anything less than a detailed analysis of the micro-structure is likely to be inadequate and in this it must be remembered that the interaction between electrical double layers which overlap with one another is likely to be important.

4.1 INTRODUCTION

It has been suggested that the relationship of surface chemistry to soil science is similar to that of biochemistry to biology. Certainly the fact that surfaces of soil particles are extensive and reactive leads to a dominance of surface chemistry in soil behaviour, but it is not an exclusive relationship, because many precipitation reactions, oxidation and reduction processes, and biological reactions take place more or less independently of the surface processes. Nevertheless it is difficult to understand soil properties fully without an appreciation of the nature and extent of the surfaces of the soil constituents, and this chapter is devoted to a discussion of this topic.

Rainfed agriculture occupies about 1.22 billion hectare (Bha) area worldwide, which is about 82% of total area (1.5 Bha) under agriculture (Yadav et al., 2006) and contributes nearly 58% to the global food basket. It is practiced under a wide variety of agro-climatic, edaphic and socio-economic conditions and globally, rainfed agriculture accounts for more than 95% of farmed land in sub-Saharan Africa, 90% in Latin America, 75% in the Near East and North Africa; 65% in East Asia and 60% in South Asia (Singh et al., 2018). 

3.1 Introduction

Groundwater constitutes about 89% of the total fresh water resources in the planet. But in recent years, due to over exploitation of ground water and erratic nature of monsoon, there has been depletion of ground water across the world. Depletion of ground water has reached to the extent that it is virtually impossible to get the water table back. Even though there is a possibility of recharge of water from the other areas, the process is very slow and may take one year to replenish one meter. In view of this management of ground water has become one of the most significant issues in recent times. Added to it, there are also environmental problems such as aqua for mining, salt water intrusion, stream base flow reduction etc. For several reasons the efficient management of ground water resources through market mechanism has become difficult. Against this context the present article attempts to analyze the need for sustainable ground water management in India. The article also briefly discusses the concept of sustainable ground water management, factors affecting ground water availability, different approaches towards developing and using available ground water without adversely affecting the hydro geological balance. Further, the paper highlights strategies for sustainable groundwater management, including development of aquifers, rainwater harvesting and artificial recharge methods. The article offers some relevant policy recommendations for sustainable groundwater management in India.

The concept of sustainability in agricultural system

All forms of production systems exist today, from nomadic herding to continuous, intensive monocrop systems. Their distribution is determined by soil and climate conditions, and by social and economic factors. In very general terms, as one moves from drier to wetter areas, pastures and animals become less important, and trees more so. Population density is greatest where soils are most fertile, and management systems the most intense. Most production systems have evolved so that they are sustainable in terms of the environmental conditions prevailing at the time—including the level of demographic pressure.

The stability of agriculture all over the planet and the accessibility of food are both signi?cantly affected by Climate change. Thus, it is desperately important to create and execute Climate -resilient farming techniques and advancements that can help farmers in acclimating to the e?ects of Climate change. It should be finished right away. It examines the issues welcomed on by Climate change, fundamentals of sustainable agriculture, and the instruments and strategies that can be utilized to expand farming’s protection from Climate change. This part essentially talks about Climate -friendly creature farming, viable water system frameworks, weather conditions checking and determining, crops that can endure dry spell and flooding, coordinated bug control, and sustainable power sources. To make sustainable more Climate change-safe, this part additionally talks about the need to empower feasible land-use rehearses and to make innovative work ventures. By using these innovation and methods, farmer might add to the maintainability and versatility of the food framework.
As a result of increasing temperatures and diminishing precipitation because of Climate change, farming is enduring enormously all over the planet. This is especially evident in India, where the greater part of the populace is utilized in farming. The effect of Climate change is perhaps of the main issue the world is at present encountering. The impacts of Climate change are felt and found in each part of society, including farming. Utilizing harmless to the ecosystem circular agriculture is critical now like never before as the total populace develops. One of these strategies is farming that is circular agriculture (CRA). Its central goal is to adjust cultivating practices to an evolving environment. Consistently, new people enter the earth. To take care of the growing populace, the land is feeling the squeeze to give more food, fiber, and fuel. Consistently, new people are brought into the world. Thus, the land is feeling the squeeze to create more food, fiber, and fuel to take care of the populace that is extending. As well as expanding crop efficiency, more Climate tough agricultural methods would likewise work on the soundness of the dirt and the biological system

Abstract
 
India shares 16% of the world population, while its land is only 2% of the total geographical area of the world. Naturally, the pressure on the land is often beyond its carrying capacity. Therefore, the productive lands, especially the farmlands in the India are in the constant process of various degrees of degradation and are fast turning into wastelands. At present, approximately 68.35 million hectare area of the land is lying as wastelands in India. Out of these lands, approximately 50% lands are such non-forest lands, which can be made fertile again if treated properly. It was unprotected non-forestlands, which suffered the maximum degradation mainly due to the tremendous biotic pressure on it. In the last 50 years it is India's lush green village forests and woodlots have been deforested to the maximum. 

“Sustainable Water Resources Management Strategies” embarks on a comprehensive exploration of the paramount challenges and essential solutions for safeguarding our planet’s most precious resource: water. This recognizes that water is not merely a commodity but the very lifeblood of ecosystems, a cornerstone of human health, a critical input for food production, and an indispensable element for industrial progress and societal well-being. Building upon a fundamental understanding of the intricate hydrological cycle, the distribution of global water resources, and the escalating anthropogenic pressures they face, we now turn our attention to the proactive and forwardthinking approaches that define sustainable water resources management. • In an era marked by increasing environmental consciousness and the stark realities of climate change, the traditional paradigms of water management are proving inadequate. Growing populations, rapid urbanization, and the expansion of industrial activities place unprecedented demands on both the quantity and quality of available water. Furthermore, the erratic and often extreme

Introduction

Though the potential benefits generated by the drip irrigation method are apparent, the adoption of drip irrigation is yet to be widely promoted across different regions and states in India. Several factors such as huge initial investment, small size of holding, lack of technical support, nature of cropping pattern, access to water and socio-economic conditions of farmers etc. (Namara et al, 2005, Suresh Kumar, 2012) are constraining adoption of drip irrigation. In some cases, even after the adoption of drip irrigation, the farmers, particularly, the small farmers have often discontinued use of drip irrigation for several reasons such as due to lack of maintenance, irrelevant cultural background, and unreliable water supply (Kulecho and Weatherhead, 2005).