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Read this essay to learn about soil. After reading this essay you will learn about: 1. Meaning of Soil 2. Life on Soil 3. Formation of Soil 4. Classes 5. Monitoring Requirements.
Essay Contents:
- Essay on the Meaning of Soil
- Essay on the Life on Soil
- Essay on the Formation of Soil
- Essay on the Classes of Soil
- Essay on the Monitoring Requirements of Soil
Essay # 1. Meaning of Soil:
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Soil is one of the most significant ecological factors, which is derived from the transformation of surface rocks. It is nothing but soil on which plants depend for their nutrients, water and mineral supply and anchorage. It constitutes an important medium where in numerous animals live. In fact, soil of a nation is its most valuable material heritage.
The importance of soil may be realised from the statement of Sunder Lal Bahuguna (1987). The eternal truth that soil and water are the two significant capitals of mankind and the natural forests are the mother of rivers and the factories for manufacturing soil.
The soil may also be divided into three major types:
(a) Zonal soils,
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(b) Intra- zonal soils, and
(c) Azonal soils.
Essay # 2. Life on Soil:
Life on earth depends directly on the living soil and the aquatic eco-system of rivers. Without fertile soil and the microbial fauna that inhabit it, food would not grow, dead things would not decay and nutrients would not be recycled. Yet the earth’s soils are being stripped away, rendered sterile and contaminated with toxic chemicals at a rate that cannot be sustained.
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An estimate (1990) showed that 10% of the fertile soil of the planet has been transformed by human activities from forest into desert, while 25% or more is at risk. Cropland is already scarce in many of the developing countries and is getting scarcer with the expansion of urbanization.
Essay # 3. Formation of Soil:
Soil system is indeed very complex and dynamic. Soil is actually formed as a result of long term process of complex interactions, disintegration and decomposition of rocks due to weathering leading to the production of mineral matrix in close association with interstitial organic matter.
Although soils are formed from the underlying rocks, these may be transported to long distances by rivers, glaciers and strong winds. Sand and clay constitute the hard mineral fractions of the soil. Actually humus mixed with sand and clay results in the formation of soil.
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The whole process of soil formation involves two stages:
i. Weathering process
ii. Soil Development or Pedogenesis.
i. Weathering Process:
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It involves the breakdown of bigger rocks into fine, smaller mineral particles and weathering process may be physical as well as chemical.
Physical Weathering includes the following processes:
(a) Heating-cooling
(b) Freezing
(c) Glaciation
(d) Solution
(e) Sandblast.
Chemical Weathering includes:
(a) Hydration
(b) Hydrolysis
(c) Carbonation
(d) Redox process
(e) Chelation etc.
ii. Soil Development or Pedogenesis:
It is the modification of mineral matter through interaction between biological, topographic and climatic effects which leads to the development of a number of layers-horizons of soil known as soil profile.
Factors Affecting Soil Formation:
a. Active Factors:
Active factors involved in the soil formation are mainly rainfall, temperature, wind, humidity and evaporation.
b. Passive Factors:
These are parent materials and topography which influences the aeration, texture and chemical characteristics of the soil.
c. Biospheric Factors:
Living organisms are very important in soil development as they speed up and modify the physico-chemical processes in the soil.
Soil is the loose surface material of land in which plant grows. It is one of the most important ecological factors. The process of soil formation is very complex involving a number of physical, chemical and biological transformations.
The topmost layer of the soil is comparatively more rich in nutrients and supports maximum bio-forms. This layer is composed of minerals of various sizes and organic matters along with pore space filled with air and water.
The deeper soil layers varies distinctly in the composition with respect to particles, nutrients and other associated properties. The soil, thus, is made up of a number of zones and the profile characteristics of these zones vary in number and composition from place to place. As most soil forming processes tend to act from the top down, soil develops a vertical structure referred to as the soil profile.
Essay # 4. Classes of Soil:
These are further sub-divided into suborders. Based on the particle size distributing pattern, the soil classes are:
(a) Clay,
(b) Silty clay,
(c) Sandy clay,
(d) Clay loam,
(e) Silty clay loam,
(f) Sandy clay loam,
(g) Silt loam,
(h) Sandy silt loam,
(i) Sandy loam,
(j) Loamy sand, and
(k) Sand.
The above-mentioned soil classes are given in the textural triangle (Fig. 4.66). Stones and gravels are excluded from the textural classes.
In soil the nutrients undergo addition and losses and these nutrient cycling’s make the balance of the organic and inorganic constituent of the soil. The biological spectrum of soil comprises of a large number of biota such as algae, fungi, bacteria, actinomycetes, micro-arthropods, protozoans, nematodes etc.
Essay # 5. Monitoring Requirements of Soil:
i. Indicators and Measurements:
Effective monitoring requires that there is clear statement of its purpose. An important distinction is between the tracking of indicators and the collection of measurements. Indicators are chosen to be representative of changes in relation to targets, which are often usefully linked to outcomes.
These outcomes may or may not be capable of physical definition, for example increased awareness of the value of soil may be an important outcome from effective soil protection policy but cannot be measured physically. Remote sensing techniques provide measurements. They are useful for indicator assessment where physical measurements can be related to targets and outcomes.
Potential indicators with regard to soil related environmental outcomes, including the following headline (main) indicators are:
i. Activity on soil information web-sites as an indicator of awareness of soil.
ii. Trends in the natural area of soil, as affected by marine erosion and accretion.
iii. Proportion of soil area in non-land use.
iv. Above ground biomass production, as an indicator of continuing biomass productivity of soil.
v. Proportion of brownfield soil area under woodland.
vi. Area of agricultural soil converted to woodland.
vii. Current area of specific soil-related habitats (bog, moorland, etc.).
viii. Soil organic carbon content.
ix. Topsoil pH, as an indicator of acidification/alkalinity change.
x. Soil buffering capacity, indicated by base saturation.
xi. River basin hydrograph responses, as an indicator of soil hydrological performance within catchments.
xiii. Eutrophication events, as an indicator of nutrient “breakthrough” from soil system.
xiv. Area of Greenfield soil area taken into the built environment.
xv. Area of soil within land under statutory protection (nature conservation, etc.).
xvi. Change in area of soil ploughed, as an indicator of potential damage to archaeological heritage.
xvii. Change in depth of cultivation, as an indicator of potential damage to archaeological heritage.
ii. Variety and Spatial Variability:
Establishment and evaluation of soil inventories is a pre-condition for effective monitoring and remote sensing has an important potential for this task. Meaningful soil monitoring depends on knowing which soils exist where, what ecological capacities they represent, and how they respond to different pressures. This knowledge and understanding is critical to determining acceptable trends and targets for indicators.
The spatial sensitivity of soil monitoring techniques is important, because of the high spatial variability of soil types, conditions and uses. Important soil populations may not be discerned if monitoring methods lack sufficient spatial precision. Evaluation of different soil monitoring options requires that the spatial variability of soil is known adequately.
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