eChapters

Structural landforms are landforms that are created due to the underlying geological structures of the earth's crust. These structures can include folds, faults, and other features that have been formed due to the tectonic forces that have shaped the earth's surface over millions of years.

Examples of structural landforms include mountain ranges, plateaus, and rift valleys. Mountain ranges are formed due to the upliftment of the earth's crust along a fault line or due to the folding of the earth's crust. Plateaus are flat-topped landforms that are formed due to the upliftment of a large area of the earth's crust. Rift valleys are formed due to the stretching and pulling apart of the earth's crust along a fault line.

Denudational landforms, on the other hand, are landforms that are created due to the process of erosion and weathering. These landforms are formed due to the gradual wearing down of the earth's surface by natural forces such as wind, water, and ice.

Rock

A rock is a solid, naturally occurring substance composed of minerals or mineraloids. It is typically formed through geological processes, such as cooling and solidification of molten lava or magma, or by the deposition and compaction of sediment over time. Rocks are classified into three main types based on their origin: igneous, sedimentary, and metamorphic.

Igneous rocks: Formed from the cooling and solidification of molten lava or magma. Examples include granite, basalt, and obsidian.

Sedimentary rocks: Formed from the accumulation and compaction of sediment, such as sand, mud, or organic matter, over long periods. Examples include sandstone, limestone, and shale.

Metamorphic rocks: Formed from the transformation of existing rocks under high temperature and pressure conditions. They undergo changes in mineral composition, texture, and structure. Examples include marble, slate, and gneiss.

Rocks serve as the building blocks of the Earth's crust and are an essential part of the geological processes that shape the planet. They can provide valuable information about Earth's history, including the formation of mountains, the movement of continents, and the presence of ancient life forms. Rocks are also used in various practical applications, such as construction, road building, and the production of minerals and resources.

Geomorphological mapping is the process of creating detailed maps that illustrate the physical features of the Earth's surface, including landforms, soil types, vegetation, and water resources. These maps can be used to better understand the underlying geology and topography of a region, and can be used for a variety of purposes, such as land-use planning, environmental management, and geological hazard assessment.

Geomorphological maps are typically created using a combination of field observations, aerial photography, and remote sensing data. Field observations involve physically visiting a site and making detailed observations of the landforms, soil types, and vegetation. Aerial photography involves taking high-resolution photographs of the Earth's surface from an airplane or satellite, which can be used to create detailed maps of the area. Remote sensing data can also be used to create geomorphological maps, including data from satellites, radar, and LiDAR (Light Detection and Ranging) systems. These technologies allow scientists to gather data about the Earth's surface without physically visiting the site, and can provide highly accurate information about the topography, geology, and vegetation of an area. The resulting maps can be used for a variety of purposes, including land-use planning, natural resource management, and hazard assessment. For example, geomorphological maps can be used to identify areas of high risk for landslides, floods, or earthquakes, and can be used to develop strategies for managing these hazards.

For the protection of all the factors of environment, laws were formed and amended from time to time as per the requirement. There are many acts according to the main factors and separate laws, for the enforcement. Also, the are some control acts, which can be implemented by states for the local environmental problems.

Experiments at Central Soil Salinity Research Institute (CSSRI), Kamal, India showed that alkali soils are not always high in available P and rice and wheat significantly responded to addition of P (Pathak et al., 1975).

The availability of phosphorus in soil either native or added is limited by fixation and precipitation mechanisms. The organic acids released during decomposition of organic matter influences the soil pH, form stable complexes with cations responsible for P fixation and thus increases the availability (Tiwari et al., 1980).

The use of bulky organic manures (Maurya and Ghosh, 1972; Chaudhary et al., 1981) and green manures (Prabhakar et al., 1972; Sharma et al., 2000) has been found very beneficial for P management of saline and alkali soils as these improve the soil physical condition and the availability of soil phosphates.

19.1. Plant Available Fraction of Nickel, Cadmium, Lead and Chromium

The DTPA method was originally developed to extract Mn, Cu, Fe and Zn from slightly acidic to alkaline soils (Lindsay and Norvell, 1978), but in some cases it can be used for other metals also such as Nickel (Ni), Cadmium (Cd), Lead (Pb) and Chromium (Cr). Among them Ni is considered as an essential micronutrient. The DTPA is used to extract soil metals by forming chelates with free metals in solution, which lowers their ionic activities so that additional quantities of metal are released from the soil until equilibrium is attained. Triehanolamine (TEA) is used to buffer the extracting solution at pH 7.3 in an attempt to optimize the extraction of various metals. Calcium chloride is included in the extracting solution to minimize dissolution of CaCO₃.

The major source of water supply on the earth is precipitation. The water received at the earth’s surface from the atmosphere either in solid or liquid form is called precipitation. The water received in solid form may be snow or hail. The precipitation is seasonal in character in many parts of the world. The precipitation may occur due to –
• Conventional physical process
• Orographic effect and
• Convergence of air masses
3.1. Conventional Physical Process
It occurs when the air on the surface of the earth and few metres above the surface of the earth is heated by absorbing long wave radiation emitted by the earth’s surface. As the air is heated, it becomes lighter. The water vapour formed due to evaporation from the soil surface or water bodies will mix with the air and the air will be moist. When the moist air gets heated it becomes lighter and rises vertically upwards. After reaching certain height, the air gets cooled enough to get saturated with water vapour. The moisture in the saturated air will condense on small solid particles to form tiny drops. These solid particles may be dust or smoke or solid particles suspended in the atmosphere and are called aerosols.

It is estimated that the world requires nearly 70 per cent increase in agriculture production to meet the demand for food by the year 2050 based on current trends in population growth it can be achieved either by increasing land under cultivation (which is not possible), increasing the availability of more water for agriculture and efficient utilisation of available land and water resources. The best available option is to increase in productivity of unit of land for unit water. However, the availability of water for agriculture production cannot be presumed to be same year after year as the major source of water is precipitation more known for its uncertainty due to change in weather patterns from season to season and year to year all over the world. The element of uncertainty is increasing since the beginning of the present century due to climate change under the present circumstance, the crop production is practiced -
• In Irrigated Areas
• In Rainfed Areas
• Under Conserved Moisture Condition Without Any Source Of Irrigation
For increasing crop production under irrigated condition, it is necessary to identify crops and varieties that can produce more yield per unit of water even when there is some decrease in availability of water through irrigation. Therefore, the concept of water production function is used for evaluation of water use efficiency of the crops.

Stress is force per unit area. When matter is subjected to stress; it may undergo changes in size, shape and displacement. Plants are grown in open environment and are likely to experience stress due to environmental conditions or when subjected to pests and diseases. The stress experienced by plants due to environmental conditions is called abiotic stresses. These include stresses caused by weather factors and climatic conditions and include moisture stress and thermal stress. The plants may also experience stress due to strong winds, dryness and as well as humid conditions (Fig.8.1).
The plants are generally classified into three types depending upon the ability to cope up with moisture stress as exhibited by-
• Drought resistance
• Drought tolerance
• Drought adaptations
The moisture stress may be to shortage of Water Compared to its requirements for evapotranspiration and metabolic activities. The plants may also suffer moisture

The term soil organic matter (SOM) includes any material that is produced originally by soil organisms (plant or animal) that is returned to the soil and undergoes decomposition process. At any point in time, it consists of an array of materials, ranging from the intact original tissues of plants and animals to the substantially decomposed mixture of materials known as humus (Fig.1.1). Most soil organic matter originates from plant tissues. Plant residues contain 60 - 90 per cent of moisture and the remaining dry matter consists mostly of carbon, oxygen, hydrogen, with smaller amounts of sulphur, nitrogen, phosphorus, potassium, calcium and magnesium. Though present in small amounts, these nutrients are of great significance from the standpoint of soil fertility.

Remote sensing involves measurement of the physical properties of a body without actual contact with it. It is based on the reflectance when the electromagnetic radiation is incident upon a body or surface. The spectral characteristics of the reflected radiation vary depending upon the nature and condition of the surface. In case of vegetation, it absorbs light and can reflect light in the visible range. The leaf pigments dominate the reflectance properties (Fig.9.1). The radiation bands within which the reflectance of electromagnetic radiation takes place are classified as follows-
Spectrum Wave Length (nm)
Visible 400-700
Near Infrared 701-1300
Middle infrared 1301-2500
Far infrared >3000

9.1. Vegetation Indices
The vegetation index is a mathematical expression that uses spectral imaging data to characterize the health and growth of the vegetation indices are calculated using data collected by remote sensors like Satellites. The vegetation indices have wide range of applications in agriculture and hydrology including
• Classification of vegetation
• Apex health of vegetation
• Changes in land cover
• Drought monitoring
• Estimation of soil moisture
• Evaluate crop growth, vigour, biomass and chlorophyll content
• Irrigation scheduling

Soil organic matter makes up only a few per cent of most soils, but it has a great deal of influence on soil properties and on agricultural productivity.

2.1. Quantity of Organic Matter

Based on the content of organic matter, soils are identified as mineral or organic. Mineral soils dominate most of the world’s cultivated land and may contain anything from a trace to 30 per cent of organic matter. Organic soils are naturally rich in organic matter, chiefly due to climatic reasons. Although they contain more than 30 per cent organic matter, it is precisely for this reason that they are not vital cropping soils.

The purpose of irrigation scheduling is to decide upon the amount of water to be applied for irrigation and timing of irrigation in order to avoid wastage of precious water. The irrigation scheduling is also used to determine the number of irrigations required for a crop during its growth cycle and judicious use of water depending upon the weather forecasts issued from time to time. The irrigation scheduling has to be planned for either full irrigation or supplementary irrigation depending upon the availability of water resources and the season during which crops are grown. Crops grown during the dry season requires full irrigation and crops grown during the rainy season require supplementary irrigation. The third category of irrigation is protective irrigation which is practiced in dryland areas. The protective irrigation is given when the crops are experiencing severe moisture stress due to prolonged dry spells wherever the farmers has access to small ponds and tanks developed within his own field as water harvesting structures.
10.1. Full Irrigation
Under full irrigation, the crops are provided with irrigation right from land preparation till the crop is getting ready for harvest maturity. The full irrigation will be usually planned for maximum yields of the crop (Fig.10.1).

Carbon is the cornerstone of all life on Earth. Plant tissues and microbial cells contain approximately 40 to 50% of carbon on dry weight basis. Yet, the ultimate source is the CO₂ of the atmosphere. The CO₂ is converted into organic carbon by the action of photoautotrophic organisms (higher plants and green algae). It has been estimated that the vegetation on earth’s surface consume some 1.3 x 10¹⁴ kg of CO₂ per annum which is about V₂₀ of the total CO₂ supply of the atmosphere or ¹/₁₀₀₀ of that in the ocean.

Abstract

Gastrointestinal parasitic infections particularly Haemonchus contortus infection in goats is very common and found as major nematode infections in farm condition. To chalk out the control programme and to prevent the initiation of anthelmintic resistant parasites, it is essential to know well in advance the prevalence of H. contortus infection. During the year 2009, a study was undertaken on H. contortus infection in the goat farm of ICAR Research Complex for NEH Region, Umiam, Meghalaya, which is a subtropical hill area and bioclimatograph was prepared to predict the prevalence of H. contortus infection in goats of this area. Meteorological data of this area was collected to visualize the effect of temperature, rainfall and humidity. Bioclimatographs were prepared in which total rainfall (TRF) or relative humidity (RH) is plotted against the maximum temperature (T-max) or minimum temperature (T-min) for the months and the resultant points are joined by a closed curve. The lines constituted the windows on these bioclimatographs, indicating the limit of the climatic conditions most suitable for development and survival of exogenous stages of gastrointestinal nematodes.

A watershed is an area that provides pathway to the surface or sub surface water flow to a given drainage system. The watershed is a hydrological unit. The area of watershed may vary from few hectares to thousands of square kilometres. The watershed development involves effective management of land and vegetation in order to conserve and improve the quantity of water. The watershed development is a comprehensive and sustainable solution to water conservation (Fig.13.1).
The watershed development has several advantages. It helps in
• Conservation, upgradation and utilization of natural resources particularly land, water and vegetation
• Minimise the inequalities between rainfed and irrigated areas
• Promoting cost effective adoptable simple technologies
• Supply water for domestic ,agricultural and industrial use
• Poverty alleviation and employment generation
• Reducing chemical pollution
• Adopting flood control measures by constructing water storage or impounding structures

Soil organic matter is among the most complex materials existing in nature. In addition to the organic constituents present in undecayed plant and animal tissues, soil organic matter contains living and dead microbial cells, microbially synthesized compounds and an endless array of derivatives of these materials produced as the result of microbial activity. Soil organic matter probably contains most of the naturally occurring organic compounds. Some components of soil organic matter are no doubt distinctive to the soil environment, particularly those involving inorganic-organic complexes.

6.1. Composition of Soil Organic Matter

The composition of soil organic fraction is as follows:

1. Components of organic residues undergoing decomposition

Hydrometeorology forecasting is limited to forecasting of occurrence of rainfall to a greater extent. Although several countries all over the world have developed and established hydrometorological forecasting with focus on occurrence of floods and droughts, still there is very limited success. Floods are associated with occurrence of continuous heavy rainfall due to movement of low-pressure systems like cyclones and depression overflow into rivers, reservoirs and breaching of bunds. In countries like India, the floods occur on the average in 70 lakh hectors of area and the economic loss due to floods and expenditure on relief operations mounting year after year besides loss of life. Foods occur at all of a sudden leaving little time for planning mitigation or rescue operation. Flood forecasting in based on impact assessment of heavy rainfall assessments to identify the exact area that is likely to be affected. It requires more intensive research. Forecasting of droughts is still an area of serious concern. There is need to strengthen regional capabilities to develop forecasting techniques for occurrence of flood and droughts through proper analysis of historical data in conjunction with meteorological forecasts and remote sensing data. Though flood alerts are issued, the identification of exact area and the extent to which flood impacts are not very clear most of the times heavy rainfall warnings are not just sufficient until and unless the vulnerable areas can be clearly specified. The medium range forecasting will be extremely useful for issuing flood alerts.
14.1. Forecasting Droughts
Long range forecasting of seasonal rainfall can indicate the possibility of receiving excess or deficit rainfall over larger regions. In India, there is considerable progress in development of long range forecast of Southwest monsoon rainfall. This forecast also indicating the regions which may get surplus or deficit rainfall and for indifferent parts of a given region as well. However, there is serious dearth of local expertise to further analyse and interpret the long-range forecast for a given area on the basis of local climate data. The advantages of reliable long-range forecast are still unexpected. Almost one fifth of the area in India gets affected by draught most of the years. The drought affects are more severe in arid and semi arid regions. Prediction of occurrence of drought and its intensity, period of occurrence and the areas to be affected by drought is very important. During recent years, there is considerable increase in the occurrence of droughts due to climate change which is attributed mainly to atmospheric pollution. The physics of the pollution is consistent and not the policies support in handling hydrometerological disasters. There are instances where in flood and droughts occurred in the same

Abstract

Climate change is a long-term change in the statistical distribution of weather patterns over periods of time that range from decades to millions of years. It may be a change in the average weather conditions or a change in the distribution of weather events with respect to an average. Climate change may be limited to a specific region, or may occur across the whole Earth.Since, time immemorial human beings have attempted to predict the disease occurrence informally by mere observing the changes in pattern of weather parameters. But the present scenario has been very much altered with the incessant and irrational use of natural resources exposing the atmosphere to the enormous encumbrance. Excessive CO₂ emissions, deforestation and injudicious use of chemicals in agricultural fields have ultimately led to the climate change, which needs an absolute engrossment. Climate change has also invited the emergence and resurgence of many of the pest and diseases posing a grave challenge to manage them. So there is a need for immediate action through Government policies and scientific community to combat the situation. Disease forecasting models may be one of the rescuing options to mitigate the problems of agriculture.

Practically every aspect of the chemistry of heavy metals in soil is related to the formation of complexes with organic matter. While monovalent cations (Na+, K+, etc.) are held mainly by simple cation exchange through the formation of salts with COOH groups (RCOONa, RCOOK), multivalent cations (Cu²+, Zn²+, Mn²+, etc.) form coordinate linkages with organic molecules.

A schematic diagram showing organic matter reactions involving metal ions in soils is given in Fig. 9.1. The metals present in the solution phase as charged species and as soluble metal-organic complexes (MChe), are shown to be influenced by the activities of higher plants and microbes, both of which serve as sources of water-soluble ligands for complex formation; some metals are held in insoluble organic complexes and are non-leachable and relatively unavailable to plants.