Wednesday, 19 June 2013

WATER

What is water?
Water is a basic molecule made up of two hydrogen atoms and one oxygen atom. When these three atoms come together, they form a strong bond that is difficult to break. The strength of this bond keeps a water molecule together for millions and even billons of years. Water can be a liquid, a solid, or a gas. Liquid water flows. Solid water is ice. Water in the form of a gas is called water vapor.

Water is one of the most common substances on the Earth. Covering over 70% of the surface of the Earth, it is easy to find. Even in a desert it is not hard to find water, if you know where to look, and is vital for all known forms of life
Scientists believe that the amount of water on Earth does not change appreciatively over time. In other words, the amount of water that is on the Earth today is the same amount that was on the Earth during the reign of the dinosaurs.
Water is used in a number of ways that you would never expect. From automobile tires to hamburgers, water is essential in the production of many everyday items. Here are just a few examples, as well as some other water-related trivia.
How much water does it take to process a quarter pound of hamburger?
Approximately one gallon
How much water does it take to produce one ton of steel?
62,600 gallons
How much water is used to produce a single day’s supply of U.S. newsprint?
300 million gallons
What is the total amount of water used to manufacture a new car, including new tires?
39,090 gallons per car

How much water must a dairy cow drink to produce one gallon of milk?
Four gallons
How much water is used during the growing/production of a chicken?
400 gallons
How much water is used during the growing/production of almonds?
12 gallons
How much water is used during the growing/production of french fries?
6 gallons
How much water is used during the growing/production of a single orange?
13.8 gallons
How much water is used during the growing/production of a watermelon?
100 gallons
How much water is used during the growing/production of a loaf of bread?
150 gallons
How much water is used during the growing/production of a tomato?
3 gallons
How much water us used during the production of an egg?
120 gallons
Water is the only substance found on earth naturally in three forms.
(Solid, liquid and gas)
Does water regulate the earth’s temperature?
Yes (it is a natural insulator)
At what temperature does water freeze?
32 degrees F, 0 degrees C
At what temperature does water vaporize?
212 degrees F, 100 degrees C
How long can a person live without food?
More than a month 
How long can a person live without water?
Approximately one week, depending upon conditions
How much of the human body is water?
66%
How much of the earth’s surface is water?
80%
How much water must a person consume per day to maintain health?
2.5 quarts from all sources (i.e. water, food)
Of all the earth’s water, how much is ocean or seas?
97%
How much of the world’s water is frozen and therefore unusable?
2%
How much of the earth’s water is suitable for drinking water?
1%
Is it possible for me to drink water that was part of the dinosaur era?
Yes - water is constantly recycled
What is the most common substance found on earth?
Water
How much water does the average residence use during a year?
Over 100,000 gallons (indoors and outside)
How much water does an individual use daily?
Over 100 gallons (all uses)
How many community public water systems are there in the United States?
54,000
How much water do these utilities process daily?
38 billion gallons
What does it cost to operate the water systems throughout the country annually?
Over $3.5 billion
How many miles of pipeline and aqueducts are in the United States and Canada?
Approximately one million miles, or enough to circle the earth 40 times
What were the first water pipes made from in the US?
Fire charred bored logs
Where was the first municipal water filtration works opened and when?
Paisley, Scotland in 1832
Of the nation’s community water supplies, what percentage are investor-owned?
15 %
How many households use private wells for their water supply?
More than 13 million
How much water is used to flush a toilet?
2-7 gallons
How much water is used in the average five-minute shower?
15-25 gallons
How much water is used on the average for an automatic dishwasher?
9-12 gallons
On the average, how much is used to hand wash dishes?
9-20 gallons
How much does one gallon of water weigh?
8.34 pounds
What is the weight of water in one cubic foot?
62.4 pounds
How much water drops with an inch of rain on one acre of ground?
27,154 gallons, which weighs 113 tons
Imfortance of water in our life

Think about the different ways you use water. You drink water when you are thirsty. You take a bath and wash your clothes with water. You water the grass or other plants. You swim in water. Water pouring over huge dams may even make the electricity that lights up your home.
About three-quarters of Earth’s surface is water. Living things are mostly made up of water. Without water, there would be no life on Earth.

Apart of drinking water is importance in agricultural activities even arrigation
The most important use of water in agriculture is for irrigation, which is a key component to produce enough food.


FOREST CONSERVATION


INTRODUCTION

Conservation, sustainable use and protection of natural resources including plants, animals, mineral deposits, soils, clean water, clean air, and fossil fuels such as coal, petroleum, and natural gas. Natural resources are grouped into two categories, renewable and nonrenewable. A renewable resource is one that may be replaced over time by natural processes, such as fish populations or natural vegetation, or is inexhaustible, such as solar energy. The goal of renewable resource conservation is to ensure that such resources are not consumed faster than they are replaced. Nonrenewable resources are those in limited supply that cannot be replaced or can be replaced only over extremely long periods of time. Nonrenewable resources include fossil fuels and mineral deposits, such as iron ore and gold ore. Conservation activities for nonrenewable resources focus on maintaining an adequate supply of these resources well into the future.
Natural resources are conserved for their biological, economic, and recreational values, as well as their natural beauty and importance to local cultures. For example, tropical rain forests are protected for their important role in both global ecology and the economic livelihood of the local culture; a coral reef may be protected for its recreational value for scuba divers; and a scenic river may be protected for its natural beauty.
Conservation conflicts arise when natural-resource shortages develop in the face of steadily increasing demands from a growing human population. Controversy frequently surrounds how a resource should be used, or allocated, and for whom. For example, a river may supply water for agricultural irrigation, habitat for fish, and water-generated electricity for a factory. Farmers, fishers, and industry leaders vie for unrestricted access to this river, but such freedom could destroy the resource, and conservation methods are necessary to protect the river for future use.
Conflicts worsen when a natural resource crosses political boundaries. For example, the headwaters, or source, of a major river may be located in a different country than the country through which the river flows. There is no guarantee that the river source will be protected to accommodate resource needs downstream. In addition, the way in which one natural resource is managed has a direct effect upon other natural resources. Cutting down a forest near a river, for instance, increases erosion, the wearing away of topsoil, and can lead to flooding. Eroded soil and silt cloud the river and adversely affect many organisms such as fish and important aquatic plants that require clean, clear freshwater for survival.
Forest  conservation
Forests provide many social, economic, and environmental benefits. In addition to timber and paper products, forests provide wildlife habitat and recreational opportunities, prevent soil erosion and flooding, help provide clean air and water, and contain tremendous biodiversity. Forests are also an important defense against global climate change. Through the process of photosynthesis, forests produce life-giving oxygen and consume huge amounts of carbon dioxide, the atmospheric chemical most responsible for global warming. By decreasing the amount of carbon dioxide in the atmosphere, forests may reduce the effects of global warming.
However, huge areas of the richest forests in the world have been cleared for wood fuel, timber products, agriculture, and livestock. These forests are rapidly disappearing. The tropical rain forests of the Brazilian Amazon River basin were cut down at an estimated rate of 14 million hectares (35 million acres) each year—an area about the size of the state of Wisconsin—in the 1990s. The countries with the most tropical forests tend to be developing and overpopulated nations in the southern hemisphere. Due to poor economies, people resort to clearing the forest and planting crops in order to survive. While there have been effective efforts to stop deforestation directly through boycotts of multinational corporations responsible for exploitative logging, the most effective conservation policies in these countries have been efforts to relieve poverty and expand access to education and health care.

FOREST


The Role of Forests
Forests provide habitat for a wide variety of plants and animals and perform many other important functions that affect humans. Photosynthesis is the chemical process in the leaves that uses sunlight and carbon dioxide to produce energy-supplying sugars for the tree or plant—in the process the foliage of the plants and trees gives off pure oxygen for breathing. Forests also prevent erosion, the wearing away of soil by wind and rain. In bare lanscapes with little or no vegetation, heavy rains fall uniformly over large areas and can wash soil into rivers and streams and cause landslides and flooding. This leads to ecosystems that are deprived of both water and soil, which are quickly carried away in rivers and streams. In forested areas the forest canopy (treetops) intercepts and gradually re-distributes precipitation that would otherwise cause this flooding and erosion—some of the precipitation flows down the bark of the trunks as stemflow, the rest percolates through the branches and foliage as throughfall. This slower and nonuniform distribution of the rain ensures that soil and water will not be immediately carried away. In addition, the roots of the trees and other vegetation hold the soil in place and prevent flooding and clouding of streams and rivers. Forests also increase the ability of the land to capture and store valuable water. The canopy is especially efficient at capturing water from fog—condensed, cloudlike water vapor—which it distributes, like precipitation, into the vegetation and soil. Water stored in tree roots, trunks, stems, and foliage, as well as the soil of the forest floor, enables forests to maintain an even flow of water in rivers and streams in times of heavy precipitation or drought.
Forest, plant community, predominantly of trees or other woody vegetation, occupying an extensive area of land. In its natural state, a forest remains in a relatively fixed, self-regulated condition over a long period of time. Climate, soil, and the topography of the region determine the characteristic trees of a forest. In local environments, dominant species of trees are characteristically associated with certain shrubs and herbs. The type of vegetation on the forest floor is influenced by the larger and taller plants, but because low vegetation affects the organic composition of the soil, the influence is reciprocal. Disturbances such as a forest fire or timber harvesting may result in a shift to another forest type (see Forest Fires; Lumber Industry). Left undisturbed, ecological succession will eventually result in a climax forest community (see Ecology). Human intervention is practiced to maintain some desirable forest types.

Forests may be divided into the following eight general types on the basis of leaf characteristics and climate.

1.      Deciduous forests of the temperate regions are the typical formation of the eastern United States. Two subtypes exist; forests of the same latitude in the northern and southern hemispheres are radically different, probably due to the continental climate of the northern hemisphere and the oceanic climate of the southern.
2.      Deciduous monsoon forests are characteristic of Bengal and Myanmar (formerly known as Burma) and common throughout Southeast Asia and India; they are also found along the Pacific coastal regions of Mexico and Central America. The climate is characterized by heavy daily rainfall, seasonally relieved by dry periods during which the trees shed their leaves.

3.      Tropical savanna forests are found in regions such as the campos of Brazil, where forest and grassland meet. Savannas, which occur widely in Africa and South America, are dominated by grasses and sedges, with open stands of widely spaced trees that are frequently thorny. Some savannas are created by fire or by grazing and browsing mammals (see Savanna).

4.      Northern coniferous forests form a worldwide belt in subarctic and alpine regions of the northern hemisphere. Gnarled scrub trees dominate at the northern tree line and on mountaintops (see Tundra). Spruce and fir trees are characteristic of the more northerly forests; pine, larch, and hemlock dominate farther south. These forests usually occupy formerly glaciated regions and occur in association with lakes, bogs, and rivers.


1.      Tropical rain forests are characteristic of central Africa and the Amazon watershed. Plant growth is profuse, and because the fall and regrowth of leaves occur gradually throughout each year, the forest is always active. Tree species are highly diverse but usually have smooth, straight trunks and large, simple leaves. Large vines are common, but the tangled growth of a jungle occurs only where the normal forest area has been abused or at a river’s edge.
2.       Temperate evergreen forests are found in the subtropical regions of North America and the Caribbean islands that have a warm maritime climate. The type is best developed along the Gulf Coast and in the Florida Everglades. The characteristic trees are live oak, magnolia, palms, and bromeliads.
3.      Temperate rain forests, with broad-leaved evergreen trees, are common on Mediterranean coasts. Rainfall may be low, but the ocean-cooled air is moisture laden, and fogs are frequent. In the United States the temperate West Coast rain forests are dominated by hemlock, cedar, spruce, fir, and redwood.

DISEASES AND PESTS
Insects and diseases are a continuing menace to forests. Various insects, such as the gypsy moth, the tussock moth, and the spruce budworm, devastate extensive areas by defoliation. Other insects serve as carriers for the causative agents of diseases that destroy trees. Parasitic tree diseases may be caused by bacteria, fungi, viruses, and nematodes, or by such parasitic plants as the mistletoe or dodder. Noninfectious diseases of trees include sunscald; drought injury; root drowning, or suffocation; nutritional excesses or deficiencies; winter injury; and injury from smoke, gases, and fumes.

Saturday, 15 June 2013

SOIL CONSERVATION



Soil, a mixture of mineral, plant, and animal materials, is essential for most plant growth and is the basic resource for agricultural production. Soil-forming processes may take thousands of years, and are slowed by natural erosion forces such as wind and rain. Humans have accelerated these erosion processes by developing the land and clearing away the vegetation that holds water and soil in place. The rapid deforestation taking place in the tropics is especially damaging because the thin layer of soil that remains is fragile and quickly washes away when exposed to the heavy tropical rains (see Desertification). Globally, agriculture accounts for 28 percent of the nearly 2 billion hectares (5 billion acres) of soil that have been degraded by human activities; overgrazing is responsible for 34 percent; and deforestation is responsible for 29 percent.
In addition to reducing deforestation and overgrazing, soil conservation involves reforming agricultural soil management methods. Some of the most effective methods include strip-cropping, alternating strips of crop and uncultivated land to minimize erosion and water runoff; contour farming, planting crops along the contours of sloping lands to minimize erosion and runoff; terracing, which also reduces erosion and runoff on slopes; growing legumes, such as clover or soybeans, to restore essential nitrogen in the soil (see Nitrogen Fixation); and minimizing tillage, or plowing, to reduce erosion

SOIL



Soil, the loose material that covers the land surfaces of Earth and supports the growth of plants. In general, soil is an unconsolidated, or loose, combination of inorganic and organic materials. The inorganic components of soil are principally the products of rocks and minerals that have been gradually broken down by weather, chemical action, and other natural processes. The organic materials are composed of debris from plants and from the decomposition of the many tiny life forms that inhabit the soil.
Soils vary widely from place to place. Many factors determine the chemical composition and physical structure of the soil at any given location. The different kinds of rocks, minerals, and other geologic materials from which the soil originally formed play a role. The kinds of plants or other vegetation that grow in the soil are also important. Topography—that is, whether the terrain is steep, flat, or some combination—is another factor. In some cases, human activity such as farming or building has caused disruption. Soils also differ in color, texture, chemical makeup, and the kinds of plants they can support.
Soil actually constitutes a living system, combining with air, water, and sunlight to sustain plant life. The essential process of photosynthesis, in which plants convert sunlight into energy, depends on exchanges that take place within the soil. Plants, in turn, serve as a vital part of the food chain for living things, including humans. Without soil there would be no vegetation—no crops for food, no forests, flowers, or grasslands. To a great extent, life on Earth depends on soil.
The study of different soil types and their properties is called soil science or pedology. Soil science plays a key role in agriculture, helping farmers to select and support the crops on their land and to maintain fertile, healthy ground for planting. Understanding soil is also important in engineering and construction. Soil engineers carry out detailed analysis of the soil prior to building roads, houses, industrial and retail complexes, and other structures.
Soil takes a great deal of time to develop—thousands or even millions of years. As such, it is effectively a nonrenewable resource. Yet even now, in many areas of the world, soil is under siege. Deforestation, over-development, and pollution from humanmade chemicals are just a few of the consequences of human activity and carelessness. As the human population grows, its demand for food from crops increases, making soil conservation crucial.
Soil formation
Soil formation is an ongoing process that proceeds through the combined effects of five soil-forming factors: parent material, climate, living organisms, topography, and time. Each combination of the five factors produces a unique type of soil that can be identified by its characteristic layers, called horizons. Soil formation is also known as pedogenesis (from the Greek words pedon, for “ground,” and genesis, meaning “birth” or “origin”).
Soil scientists also characterize soils according to how effectively they retain and transport water. Once water enters the soil from rain or irrigation, gravity comes into play, causing water to trickle downward. Water is also taken up in great quantities by the roots of plants: Plants use anywhere from 200 to 1,000 kg (440 to 2,200 lb) of water in the formation of 1 kg (2.2 lb) of dry matter. Soils differ in their capacity to retain moisture against the pull exerted by gravity and by plant roots. Coarse soils, such as those consisting of mostly of sand, tend to hold less water than do soils with finer textures, such as those with a greater proportion of clays.
Water also moves through soil pores independently of gravity. This movement can occur via capillary action, in which water molecules move because they are more attracted to the pore walls than to one another. Such movement tends to occur from wetter to drier areas of the soil. The movement from soil to plant roots can also depend on how tightly water molecules are bound to soil particles. The attraction of water molecules to each other is an example of cohesion. The attraction of water molecules to other materials, such as soil or plant roots, is a type of adhesion. These effects, which determine the so-called matric potential of the soil, depend largely on the size and arrangement of the soil particles. Another factor that can affect water movement is referred to as the osmotic potential. The osmotic potential hinges on the amount of dissolved salts in the soil. Soils high in soluble salt tend to reduce uptake of water by plant roots and seeds. The sum of the matric and osmotic potentials is called the total water potential.
In soil, water carries out the essential function of bringing mineral nutrients to plants. But the balance between water and air in the soil can be delicate. An overabundance of water will saturate the soil and fill pore spaces needed for the transport of oxygen. The resulting oxygen deficiency can kill plants. Fertile soils permit an exchange between plants and the atmosphere, as oxygen diffuses into the soil and is used by roots for respiration. In turn, the resulting carbon dioxide diffuses through pore spaces and returns to the atmosphere. This exchange is most efficient in soils with a high degree of porosity. For farmers, gardeners, landscapers, and others with a professional interest in soil health, the process of aeration—making holes in the soil surface to permit the exchange of air—is a crucial activity. The burrowing of earthworms and other soil inhabitants provides a natural and beneficial form of aeration.
For most of human history, soil has not been treated as the valuable and essentially nonrenewable resource that it is. Erosion has devastated soils worldwide as a result of overuse and misuse. In recent years, however, farmers and agricultural experts have become increasingly concerned with soil management.