eChapters

The response of plants to air pollution can be understood by analyzing the physiological and biochemical parameters of plants.

Physiological Parameters

The epidermal cells are the first to interact with the air pollutants and also lack chloroplast. Epidermal cells hence cannot remove excess sulphur through the production and release of H2S. Damage to plants by air pollutants depends upon the amount of pollutants entering the cells and their reactivity with cellular constituents. Plants regulate the entry of gaseous molecules through stomatal movement thereby affecting the photosynthesis and transpiration. Response of plants to gaseous pollutants varies from species to species. This is due to differences in the stomatal conductance, aperture size and permeability of plasma membrane (Yunus et al., 1996).

Effect of Air Pollutants on Plants
 
Elements of those air pollutants which accumulate in plants (S from SO2, heavy metals from anthropogenic emissions etc.) may be used for specific bio-indication of possible effects caused by these pollutants, and for mapping their spatial and temporal distribution. Measuring accumulated components in plants rather than directly in the environment, provides the dual advantages of an integrated rather than a momentary value, and of a biological content rather than a mere concentration (Stocker and Gluch, 1990).

Particulate Matter

Anthropogenic emissions of particulate matter include fossil fuel (diesel and petrol) combustion from mobile and stationary sources (Rogge et. al., 1993a-c), biomass burning (Forest fires, landfills, agricultural activities and incinerators) (Oros and Simoneit, 1999) natural gas (Rogee et. al., 1993c), wood (McDonald et. al., 2000) and coal combustion (Mastral and Callen, 2000).

AIR POLLUTION FROM AUTO EXHAUST

Motor vehicles are the major source of a number of pollutants, in particular carbon monoxide (CO),nitrogen oxides (NOx), unburnt hydrocarbons (HC),ozone (O3) and other photo chemical oxidants and lead (Pb) and, in smaller proportions Total Suspended Particulate Matter (TSPM), sulphur dioxide (SO2) and volatile organic compounds.

AIR

Air is a non-homogenous mixture of gases, solid particles, and liquids; It consists of gases and particles with small settling velocity that exhibit stability in a gravitational field. Atmosphere has four major layers Troposphere from 0-17km., Stratosphere from 17-50km., Mesosphere from 50-90 km. and Ionosphere is from 90-100 km. (95% of the air by weight is contained in the Troposphere i.e. from 0-17 km).

Ever since industrial revolution altered the whole gamut of economic activity at least two hundred years ago, the path of economic growth including its modified form economic development had appeared unending and limitless. The whole focus of economic activity is to produce mere goods and services for use by the mankind so that life could be more comfortable and satisfying. Increasing population and increased needs of more goods and service was also seen as a hindrance or limitation in the march towards economic growth and development.

Knowledge of structure is a basic element of biological research. Understanding structures of various degrees of complexity contributes to a better understanding of function, ontogenetic and physiologic processes, as well as phylogenetic relationships. In biological sciences, ultrastructure refers to the nanostructure of a biological specimen, such as a cell, tissue, or organ, at scales smaller than can be viewed with light microscopy. Electron microscopy (EM) has a great impact on our knowledge and understanding of ultrastructure.

Introduction

After the Second World War, isotopes have become available in sufficient quantities for use in different fields of scientific research. There has been tremendous increase in the number and scope of applications of these new tools and agricultural research is no exception. During the last quarter of a century, the use of isotopes and radiations has become one of the important tools in the solution of practical problems in the area of soil-plant nutritional studies throughout the world. In India, these studies were initiated as early as 1955 with the establishment of the Radiotracer Laboratory at the Indian Agricultural Research Institute, New Delhi. The use of these nuclear tools got further fillip in our country with the establishment of the Nuclear Research Laboratory at the Indian Agricultural Research Institute, New Delhi in 1968 as a UNDP Project on Nuclear Research in Agriculture, operated by the Joint FAO/IAEA division of the International Atomic Energy Agency. Also, the agriculture division of Bhabha Atomic Research Centre, Mumbai and the special radioisotope laboratories established by several agricultural universities had made significant contributions to the use of isotopes and radiations in agricultural research.

A new analytical technique called inductively coupled plasma emission spectroscopy has been used for simultaneous multi element analysis of biological materials and soils (Hou and Jones 2000; Wikipedia, 2010; Bradford and Cook, 1997). This technique offers advantages over AAS and other multi-element methods because matrix problems are eliminated or minimized through use of the high temperature argon plasma. Apart from multi- element capability at all concentration levels, plasmas are noted for relative freedom from chemical and ionization interferences that are common with AAS, and detection limits are equal to or better than AAS, depending on the element to be analyzed. Elements such as Al, P, S and B, which are either poorly measured at low concentrations or not possible by AAS, are readily determined with higher sensitivity by ICP.

Soil organisms play vital role in agri-ecosystem processes such as nutrient cycling, soil detoxification and organic matter decomposition. They also influence water infiltration by improving soil porosity through production of polysaccharides. Rhizosphere microorganisms help plant to acquire macro and micronutrients, produce phytohormones for better crop establishment. Soil microbes process organic matter to provide a balance of minerals and nutrients which are utilized by plants to achieve healthy and vigorous growth. Microbes also colonize on plants parts and offers protection by excluding many plant pathogens. They are the basic indicators of soil fertility and are responsible for maintaining a hospitable environment for crop growth.

Fertility of a soil can be assessed by analyzing various available nutrients present in the soil. Fertilizer recommendations for various crops and cropping sequences can be made on the basis of fertility status of a soil. Besides this, problematic soil can be ameliorated on the basis of soil test values. Among the various steps of soil testing programmes, soil sampling is the most vital step.

According to Planning Commission Report (2014), India generates about 62 million tons of municipal solid wastes (MSW) every year from urban cities. There has been a significant increase in municipal solid waste generation in India in the last few decades. This is largely due to rapid population growth and economic development in the country (Annepu, 2012). Solid waste management (SWM) has become a major environmental issue because of serious environmental implications like global warming (through green house gases emission) and contamination of toxic pollutants (like heavy metals) in surface and groundwater bodies. Solid waste management is one of the essential services to be provided by municipal authorities in the country to keep urban areas clean. Out of total waste generated in India, only 12.45% waste is scientifically processed and rest is disposed in open dumps (CPCB Report, 2013). Although, incineration of solid wastes is being followed in many places for energy production, composting is considered most environment friendly method of SWM as it promotes recycling of nutrients in crop production.

Introduction

Use of FYM, crop residues, leaf fall, root deposition etc. has been part and parcel in agriculture. These material undergoes microbial decay over the time slowly and the major portion of it finds way back to the atmosphere. Not only that, residue burning traditionally provides a fast way to clear the agricultural field of residual biomass, facilitating further land preparation and planting. However, in addition to the loss of valuable biomass and nutrients, biomass burning leads to release of toxic gases including GHGs.

Introduction

Our soil resource is generally taken for granted for many uses. Most people don’t realize the importance of the resource and that it is fundamental for farming/agriculture. Without high quality soils, agriculture production cannot be achieved on a sustainable basis to meet ever growing demand. Thus, conservation agricultural practices are capable of improving soil health by increasing organic carbon, aggregation, improving infiltration and minimizing erosion losses.

Introduction

Organic matter in soil is the key to soil health. SOM improves many physical, chemical, and biological characteristics of the soil, including water holding capacity, cation exchange capacity, pH, buffering capacity, and chelating of micronutrients. Furthermore, well decomposed SOM improves soil structure by increasing aggregation, enhances biological activities in the soil, slowly releases nutrients, and suppresses some diseases. A loss of SOM can lead to soil erosion, loss of fertility, compaction, and general land degradation.

Introduction

The soil is the largest terrestrial pool of organic carbon, about 1150 Pg (1Pg = 10¹⁵ g) compared with about 700 Pg in the atmosphere and 600 Pg in land biota (Lal and Kimble,1997). Organic carbon level of soils reaches a fixed equilibrium that is determined by a number of interacting factors such as precipitation, temperature, soil type, tillage, cropping systems, fertilizers, the type and quantity of crop residues returned to soil, and the method of residues management. In the temperate climate, it may take about 50 years for the organic carbon of soils to reach a new equilibrium level following a change in management. However, this period is much shorter in a semiarid and arid climate and also in tropical climate like India.

Introduction

The term nitrogen use efficiency, (NUE) is widely used in research to cover problems in use of N in crop production systems. It describes N input/output ratio at different scales starting from farm levels to regional levels. An analysis of of NUE is helpful to analyze possible options for improving NUE in different crops and cropping systems. NUE at crop scale may be defined as the ratio between the yield and the N uptake by the crop. This ratio is sometimes called as the physiological NUE or utilization efficiency. High NUE can be achieved by high harvest index and a high productivity of dry matter per unit N uptake. The second component of NUE is the ratio of plant N uptake to the potentially available N. This ratio is called uptake efficiency or available N use efficiency. Enhancing the uptake efficiency of the crop is possible through enhancing the physiological uptake efficiency of the roots, enhancing root length density and matching the N supply and demand of a particular crop.

Introduction
 
Climate change is a result from emission of greenhouse gases (e.g. CO₂, CH₄, N₂O, etc.) that will cause atmospheric warming (IPCC, 2007). Climate change may be due to natural internal processes or external forcing such as modulations of the solar cycles, volcanic eruptions, and persistent anthropogenic changes in the composition of the atmosphere or in land use. Human induced changes in atmosphere composition are a major concern. Burning of fossil fuels, like oil, coal, and natural gas is adding CO₂ to the atmosphere.

Under natural conditions, the largest source of labile carbon (C) inputs to the soil is root exudates (Bertin et al., 2003; Hutsch et al., 2002; Kuzyakov 2002). Roots exude a variety of low-molecular weight organic compounds, including sugars, amino acids, organic acids (Bertin et al., 2003), but also contain hormones, vitamins, amino compounds, phenolics and sugar phosphate esters (Uren, 2001). These compounds are rapidly metabolized; for example, Hutsch et al., (2002) found that 64–86% of maize root exudates were respired by soil microorganisms. The effect of root exudates depends on the distance that they can diffuse away from rhizoplane (Gupta and Mukerji, 2002).

The diets of over two-thirds of the world’s population lack one or more essential mineral elements. This can be remedied through dietary diversification, mineral supplementation, food fortification, or increasing the concentrations and/or bioavailability of mineral elements in produce (biofortification) involving aspects of soil science, plant physiology and genetics underpinning crop biofortification strategies, as well as agronomic and genetic approaches currently taken to biofortify food crops with the mineral elements most commonly lacking in human diets: iron (Fe), zinc (Zn), copper (Cu), calcium (Ca), magnesium (Mg), iodine (I) and selenium (Se).