Chapter 10

What is desert pavement is?

A desert pavement, also called reg (in the western Sahara), serir (eastern Sahara), gibber (in Australia), or saï (central Asia) is a desert surface covered with closely packed, interlocking angular or rounded rock fragments of pebble and cobble size.

Watershed

A watershed describes an area of land that contains a common set of streams and rivers that all drain into a single larger body of water, such as a larger river, a lake or an ocean. For example, the Mississippi River watershed is an enormous watershed.

What are shelter belts?

A windbreak or shelterbelt is a plantation usually made up of one or more rows of trees or shrubs planted in such a manner as to provide shelter from the wind and to protect soil from erosion. They are commonly planted around the edges of fields on farms. ‎Windbreak aerodyna

What Proportion of the worlds water is fresh water is fresh vs. saltwater and where they are found?

About 70% of the earth's surface is covered with water. Ninety-seven percent of the water on the earth is salt water. Salt water is filled with salt and other minerals, and humans cannot drink this water. Although the salt can be removed, it is a difficult and expensive process. Two percent of the water on earth is glacier ice at the North and South Poles. This ice is fresh water and could be melted; however, it is too far away from where people live to be usable. Less than 1% of all the water on earth is fresh water that we can actually use. We use this small amount of water for drinking, transportation, heating and cooling, industry, and many other purposes.

What is the difference between humidity and relative humidity?

Absolute Humidity, often just referred to as 'the humidity', is a measure of the actual amount of water vapour in a particular sample of air: measured as a partial pressure (vapour pressure/hPa or millibars); a mixing ratio (gm water vapour/kg of dry air), dew point etc. Relative Humidity - expressed commonly as a percentage value, is the ratio of the actual amount of water vapour present in a sample (the Absolute Humidity) to that amount that would be needed to saturate that particular sample. The two terms are not interchangeable and can lead to confusion; e.g. on a cold, raw winter's day close to the east coast of England, the dew point might be 1 degC and an air temperature of just 2 degC. This would give a RH of 93%; a 'high' Relative Humidity, yet few would refer to such conditions as 'humid'. Conversely, on a hot summer's day, with a dew point of 18 degC, and an afternoon temperature of 30 degC, that's a RH of 49%; a 'low' Relative Humidity, but high Absolute Humidity. ‹ What is the 'dew point'? upDoes the dew point temperature have to be above a certain value for a thunderstorm? ›

What is an aquifer?

An aquifer is a body of saturated rock through which water can easily move. Aquifers must be both permeable and porous and include such rock types as sandstone, conglomerate, fractured limestone and unconsolidated sand and gravel.

What is the Clean Water Act?

As amended in 1972, the law became commonly known as the Clean Water Act (CWA). The 1972 amendments: Established the basic structure for regulating pollutant discharges into the waters of the United States. Gave EPA the authority to implement pollution control programs such as setting wastewater standards for industry.May 25, 2016

How is man affecting the hydrologic cycle?

As the human population has increased, so have our demands on the land. We need more food, and to make food, we need water. Irrigation is the artificial watering of land that does not get enough water through rainfall. Irrigation is used substantially by most countries, some more than others. Arid (dry) lands require far more water, as do countries that have large intensive farming communities. The problem with irrigation is that it removes water from its natural source and often causes leaching and run-off where it is used. This removal of nutrients results in farmers using more fertilisers to keep their pastures productive while the waterways become polluted. Another problem is that salt is brought up from lower levels (salination). As the human population has increased, so have our demands on the land. We need more food, and to make food, we need water. Irrigation is the artificial watering of land that does not get enough water through rainfall. Irrigation is used substantially by most countries, some more than others. Arid (dry) lands require far more water, as do countries that have large intensive farming communities. The problem with irrigation is that it removes water from its natural source and often causes leaching and run-off where it is used. This removal of nutrients results in farmers using more fertilisers to keep their pastures productive while the waterways become polluted. Another problem is that salt is brought up from lower levels (salination).

What is center pivot irrigation?

Center-pivot irrigation (sometimes called central pivot irrigation), also called waterwheel and circle irrigation, is a method of crop irrigation in which equipment rotates around a pivot and crops are watered with sprinklers.

What is compaction?

Compaction (Soil Compaction) is the process of applying energy to loose soil to consolidate it and remove any voids, thereby increasing the density and consequently its load-bearing capacity.

Condensation

Condensation is the change of water from its gaseous form (water vapor) into liquid water. Condensation generally occurs in the atmosphere when warm air rises, cools and looses its capacity to hold water vapor. As a result, excess water vapor condenses to form cloud droplets.

What is contour plowing?

Contour plowing was a method of plowing furrows that follow the curves of the land rather than straight up and down slopes. Furrows that run up and down a slope form a channel that can quickly carry away seeds and topsoil. Contour plowing forms ridges, slows the water flow and helps save precious topsoil.

Water table

Cross section showing the water table varying with surface topography as well as a perched water table The water table is the surface where the water pressure head is equal to the atmospheric pressure (where gauge pressure = 0). It may be conveniently visualized as the "surface" of the subsurface materials that are saturated with groundwater in a given vicinity. However, saturated conditions may extend above the water table as surface tension holds water in some pores below atmospheric pressure.[1] Individual points on the water table are typically measured as the elevation that the water rises to in a well screened in the shallow groundwater. The groundwater may be from infiltrating precipitation or from groundwater flowing into the aquifer. In areas with sufficient precipitation, water infiltrates through pore spaces in the soil, passing through the unsaturated zone. At increasing depths water fills in more of the pore spaces in the soils, until the zone of saturation is reached. In permeable or porous materials, such as sands and well fractured bedrock, the water table forms a relatively horizontal plane. Below the water table, in the phreatic zone, permeable units that yield groundwater are called aquifers. The ability of the aquifer to store groundwater is dependent on the primary and secondary porosity and permeability of the rock or soil. In less permeable soils, such as tight bedrock formations and historic lakebed deposits, the water table may be more difficult to define. The water table should not be confused with the water level in a deeper well. If a deeper aquifer has a lower permeable unit that confines the upward flow, then the water level in a well screened in this aquifer may rise to a level that is greater or less than the elevation of the actual water table. The elevation of the water in this deeper well is dependent upon the pressure in the deeper aquifer and is referred to as the potentiometric surface, not the water table.[1]

What affects do dams have on the surface waters?

Dams have long been acknowledged for providing electricity without the pollution of other methods, for flood protection, and for making water available for agriculture and human needs. Within recent decades, however, the environmental impacts of dams have been debated. While dams do perform important functions, their effects can be damaging to the environment. People have begun to question whether the positive contributions of some dams are outweighed by those negative effects. The damming of a river will have dramatic consequences on the nature of the environment both upstream and downstream of the dam. The magnitude of these effects are usually directly related to the size of the dam. Prior to dam construction, most natural rivers have a flow rate that varies widely throughout the year in response to varying conditions. Of course once constructed, the flow rate of the river below a dam is restricted. The dam itself and the need to control water releases for the various purposes of the particular dam result in a flow rate that has a smaller range of values and peaks that occur at times related to need rather than the dictates of nature. In cases where the entire flow has been diverted for other uses, there may no longer be any flow in the original channel below the dam. Because water is held behind the dam and often released from some depth, the temperature of the water below the dam is usually lower than it would be prior to dam emplacement. The temperature of the water flow is often constant, not reflecting the natural seasonal variations that would have been the case in the free-flowing river. Similarly, the chemistry of the water may be altered. Water exiting the lake may be higher in dissolved salts or have lower oxygen levels than would be the case for a free-flowing river. Impoundments increase the potential for evaporation from the river. Because the surface area of a lake is so great when compared to the river that supplies it, the loss of water to evaporation must be considered. In some desert areas, potential annual evaporation can be greater than 7 ft (2.1 m), meaning that over the course of one year, if no water flowed into or out of the system, the reservoir would drop in elevation by 7 ft (2.1 m). At Lake Mead on the Colorado River in Arizona and Nevada, evaporation losses in one year can be as great as 350 billion gal (1.3 trillion l). The impoundment of water behind a dam causes the velocity of the water to drop. Sediment carried by the river is dropped in the still water at the head of the lake. Below the dam, the river water flows from the clear water directly behind the dam. Because the river no longer carries any sediment, the erosive potential of the river is increased. Erosion of the channel and banks of the river below the dam will ensue. Even further downstream, sediment deprivation affects shoreline processes and biological productivity of coastal regions. This problem has occurred within the Grand Canyon below Glen Canyon Dam. After the construction of the dam was completed in 1963, erosion of the sediment along the beaches began because of the lack of incoming sediment. By the early 1990's, many beaches were in danger of disappearing. In the spring of 1996, an experimental controlled flood of the river below Glen Canyon Dam was undertaken to attempt to redistribute existing sediments along the sides of the channel. While many of the beaches were temporarily rebuilt, this redistribution of sediments was short lived. Research on this issue is continuing, however, the fundamental problem of the lack of input sediment for the river downstream of the dam remains unresolved. Read more: Dams - Impact Of Dams - Water, River, Flow, and Sediment - JRank Articles http://science.jrank.org/pages/1942/Dams-Impact-dams.html#ixzz4LB6n4m89

What is desertification?

Deforestation is the removal of existing forest. Usually, this is done to sell the existing trees as lumber. When loggers remove the trees, the general area is devastated, as these trees make quite an impact when they come down. Care must be taken by forestry administrators to require clean up efforts while harvesting forest products, and to replant the area with new seedling trees. Otherwise, an area that once was solid erosion-wise may become decimated, because of the removal of the root systems that kept the soil in place.

What is desalination where is it taking place and why is it important?

Desalination (or desalinization) - the process of removing dissolved salts from water - is a technology that has been used for centuries. References to desalination can be found as far back as the writings of Aristotle (320 BC) and Pliny the Elder (76 AD). It is widely used at sea to this day and has helped keep many early mariners alive during long ocean trips. In fact, a typical nuclear-powered U.S. aircraft carrier today uses waste reactor heat to desalinate 400,000 gallons of water per day. Significant advances in desalination technology started in the 1900's and took a major step during WW II because of the need to supply potable water to military troops operating in remote, arid areas. By the 1980's desalination technology was commercially viable and commonplace by the 1990's. Today there are more than 16,000 desalination plants worldwide, producing more than 20 billion gallons of drinkable water every day. This is expected to reach more than 30 billion gallons per day by 2020, with one third of that capacity in the Middle East. To put that number in perspective, current global water consumption is estimated to be just under 1,200 billion gallons. Why is desalination so important? The earth is a water-rich planet, to the tune of about 300 million cubic miles of water, and each cubic mile contains more than one trillion gallons. The problem is that most of that water, approximately 97 percent, is in the oceans which have an average salt content (salinity) of 35,000 parts per million by weight, and drinking that water regularly can kill us. To quote 'How Desalination Works' by Laurie Dove: "Ingesting salt signals your cells to flush water molecules to dilute the mineral. Too much salt, and this process can cause a really bad chain reaction: Your cells will be depleted of moisture, your kidneys will shut down and your brain will become damaged. The only way to offset this internal chaos is to urinate with greater frequency to expel all that salt, a remedy that could work only if you have access to lots of fresh drinking water."

What is the difference in the regional usages?

Domestic generally means relating to someone's family, home, or home country. Domestic work is work done in the home--a domestic is someone who works in a home, such as a nanny or a maid. Domestic is also used to refer to products that are produced in your country, or policies and affairs that relate to your country. Aug 15, 2016 - An industrial region is a geographic area in which a large number of manufacturing plants are located. Zoning for industrial... An agricultural region is defined as an area havinhomogeneity in relief, soil type, climatic conditions, farming practices, crops produced and crop association. ... India is a vast country and is endowed with diverse geographical conditions which are bound to bring in regional variations in agriculture.

What is drip irrigation and why is it important?

Drip Irrigation | SSWM www.sswm.info › water-use › hardware With drip irrigation , water is conveyed under pressure through a pipe system to the fields, where it drips slowly onto the soil through emitters or drippers which are located close to the plants. ... The small amount of water reduces weed growth and limits the leaching of plant nutrients down in the soil. Why Is Drip Irrigation Important To Growing Corn? 1 Greater water application uniformity and accuracy, resulting in improved water use ef ciency (WUE) and crop uniformity. 2 Reduced soil surface wetting, resulting in lower evaporation losses and weed competition. 3 Greatly reduced periods of anaerobic conditions in the root zone compared to other forms of irrigation. 4 Greater ability to manipulate soil water content at peak demand to improve eld access, minimize rutting, etc. 5 Improved disease control due to improved root zone oxygenation or reduced foliar wetting. 6 Ability to apply nutrients directly to the center of the active root zone resulting in very ef cient and immediate uptake by crop. 7 Minimize nitrate leaching loss potential to ground water, with good irrigation water management. 8 Flexibility in application timing for nutrients and other crop care products.

What is drip irrigation?

Drip irrigation is a form of irrigation that saves water and fertilizer by allowing water to drip slowly to the roots of many different plants, either onto the soil surface or directly onto the root zone, through a network of valves, pipes, tubing, and emitters.

What is erosion and how does it occur?

Erosion is a process where natural forces like water, wind, ice, and gravity wear away rocks and soil. It is a geological process, and part of the rock cycle. Erosion occurs at the Earth's surface, and has no effect on the Earth's mantle and core. Most of the energy that makes erosion happen is provided by the Sun.

Evaporation

Evaporation is a type of vaporization of a liquid that occurs from the surface of a liquid into a gaseous phase that is not saturated with the evaporating substance. The other type of vaporization is boiling, which is characterized by bubbles of saturated vapor forming in the liquid phase.

Evapotranspiration

Evapotranspiration (ET) is the sum of evaporation and plant transpiration from the Earth's land and ocean surface to the atmosphere. Evaporation accounts for the movement of water to the air from sources such as the soil, canopy interception, and waterbodies. ‎Evapotranspiration and the ... · ‎Estimating evapotranspiration

What is the Difference between green water and blue water in environmental terms?

Executive Summary Green water is that fraction of rainfall that infiltrates into the soil and is available to plants. It includes soil water holding capacity and the continual replenishment of reserves by rainfall. Green water is the largest fresh water resource, the basis of rain-fed agriculture and all life on land; and yet it has received remarkably little attention in contrast to blue water - the fraction of water that reaches rivers directly as runoff or, indirectly, through deep drainage to groundwater and stream base flow.

What is flood irrigation, center pivot irrigation and drip irrigation are?

Flood irrigation (also known as "surface irrigation") is an irrigation method used to flush standing water into a crop field. Because it must use an extraordinary amount of water, as well as pump pressure, flood irrigation is considered the least efficient and most wasteful method of irrigation available.

What is grey water?

Greywater is gently used water from your bathroom sinks, showers, tubs, and washing machines. It is not water that has come into contact with feces, either from the toilet or from washing diapers. Greywater may contain traces of dirt, food, grease, hair, and certain household cleaning products.

Ground water

Groundwater is the water found underground in the cracks and spaces in soil, sand and rock. It is stored in and moves slowly through geologic formations of soil, sand and rocks called aquifers.

What is water recharge and how does it work

Groundwater recharge or deep drainage or deep percolation is a hydrologic process where water moves downward from surface water to groundwater. Recharge is the primary method through which water enters an aquifer. This process usually occurs in the vadose zone below plant roots and is often expressed as a flux to the water table surface. Recharge occurs both naturally (through the water cycle) and through anthropogenic processes (i.e., "artificial groundwater recharge"), where rainwater and or reclaimed water is routed to the subsurface.

What is infiltration?

Infiltration is the process by which water on the ground surface enters the soil. Infiltration rate in soil science is a measure of the rate at which soil is able to absorb rainfall or irrigation. It is measured in inches per hour or millimeters per hour.

Leaching

Leaching is the loss or extraction of certain materials from a carrier into a liquid (usually, but not always a solvent). Specifically, it may refer to: Leaching (agriculture), the loss of water-soluble plant nutrients from the soil; or applying a small amount of excess irrigation to avoid soil salinity.

Precipitation

May 2, 2016 - Precipitation is water released from clouds in the form of rain, freezing rain, sleet, snow, or hail. It is the primary connection in the water cycle that provides for the delivery of atmospheric water to the Earth. Most precipitation falls as rain.

What is Evaporative loss?

No water budget would be complete without accounting for evaporation and related processes, such as transpiration and sublimation. ... Sublimation is the process by which water changes from ice or snow (a solid) to water vapor (a gas), bypassing the liquid phase.

What is the impact of overcultivation and overgrazing have on soil?

Overcultivation occurs when farmers or agriculturalists disturb the soil around crops too much. There is a certain amount of cultivation that is necessary to remove weeds and grasses that are not part of the cash crop. Too much cultivation, however, can have the opposite effect desired, injuring the plants it is supposed to nourish. The cure is simple: stop disturbing the ground by digging into it. Overgrazing occurs when cattle, horses, sheep, and other applicable livestock are kept and fed from the same spot of ground too long. The grass and existing ground cover must have some sort of recovery time to recover the vegetation that was removed, probably three to four weeks. The livestock should be rotated from pasture to pasture to allow this recovery to take place.

Percolation

Percolation is the process of a liquid slowly passing through a filter. It's how coffee is usually made. Percolation comes from the Latin word percolare, which means "to strain through." Percolation happens when liquid is strained through a filter, like when someone makes coffee.

What is soil enrichment and mineralization and how does it occur?

Phosphate is taken up by plants from soils, utilized by animals that consume plants, and returned to soils as organic residues decay in soils (Figure 1). Much of the phosphate used by living organisms becomes incorporated into organic compounds. When plant materials are returned to the soil, this organic phosphate will slowly be released as inorganic phosphate or be incorporated into more stable organic materials and become part of the soil organic matter. The release of inorganic phosphate from organic phosphates is called mineralization and is caused by microorganisms breaking down organic compounds. The activity of microorganisms is highly influenced by soil temperature and soil moisture. The process is most rapid when soils are warm and moist but well drained. Phosphate can potentially be lost through soil erosion and to a lesser extent to water running over or through the soil. Many phosphate compounds are not very soluble in water; therefore, most of the phosphate in natural systems exists in solid form. However, soil water and surface water (rivers and lakes) usually contain relatively low concentrations of dissolved (or soluble) phosphorus. Depending on the types of minerals in the area, bodies of water usually contain about 10 ppb or more of dissolved P as orthophosphate. Water bodies may also contain organic P and phosphate attached to small particles of sediment. Total phosphorus in water is all of the phosphorus in solution regardless of its form and is often the form reported in water quality studies. Algal available or bioavailable phosphorus is P that is estimated to be available to organisms like algae that are present in a lake or river. This is usually estimated by a chemical test which is designed to measure the dissolved P and the particulate P that are easily available. This is a measure of the P that is of immediate concern to water quality. The word phosphorus or P refers to the element and is also used as a general term when a particular chemical form of P is not being designated. For example, the total P content of a soil or plant material is usually expressed as percent P. However, fertilizer analyses are usually reported as percent P2O5. The phosphate form (P2O5) is a chemical produced during fertilizer analysis, but does not exist in either fertilizers or soils.

Capillary water

Popularity: Bottom 40% of words Definition of capillary water : water that remains in the soil after gravitational water is drained out, that is subject to the laws of capillary movement, and that is in the form of a film around the soil grains

what salinization is and how does it affect soil

Salinity from irrigation can occur over time wherever irrigation occurs, since almost all water (even natural rainfall) contains some dissolved salts. When the plants use the water, the salts are left behind in the soil and eventually begin to accumulate.

What is soil texture and what are its characteristics?

Soil texture describes the proportion of three sizes of soil particles and the fineness or coarseness of a soil. Soil texture may be determined in one of two ways. The percentages of sand, silt, and clay may be tested in the lab. Once tested, the textural class of the soil can be determined by referring to the textural triangle. Soils with different amounts of sand, silt, and clay are given different names. For instance, a soil containing 40 percent sand, 40 percent silt, and 20 percent clay is called loam soil. The relative amounts of sand, silt, and clay may also The texture of a soil is important because it determines soil characteristics that affect plant growth. Three of these characteristics are water-holding capacity, permeability, and soil workability. Water-holding capacity is the ability of a soil to retain water. Most plants require a steady supply of water, and it is obtained from the soil. While plants need water, they also need air in the root zone. Permeability is the ease with which air and water may pass through the soil. Soil workability is the ease with which soil may be tilled and the timing of the work.

What is water holding capacity?

Soil water holding capacity is a term that all farms should know to optimize crop production. Simply defined soil water holding capacity is the amount of water that a given soil can hold for crop use. Field capacity is the point where the soil water holding capacity has reached its maximum for the entire field.Nov 11, 2011

What is Ogallala aquifer?

The Ogallala Aquifer is a shallow water table aquifer located beneath the Great Plains in the United States. ... About 27% of the irrigated land in the United States overlies the aquifer, which yields about 30% of the ground water used for irrigation in the United States. ‎General characteristics · ‎Aquifer water balance · ‎Environmental controversies

What is a Hadley cell no how does it work?

The atmosphere transports heat throughout the globe extremely well, but present-day atmospheric characteristics prevent heat from being carried directly from the equator to the poles. Currently, there are three distinct wind cells - Hadley Cells, Ferrel Cells, and Polar Cells - that divide the troposphere into regions of essentially closed wind circulations. In this arrangement, heat from the equator generally sinks around 30° latitude where the Hadley Cells end. As a result, the warmest air does not reach the poles. If atmospheric dynamics were different, however, it is plausible that one large overturning circulation per hemisphere could exist and that wind from the low-latitudes could transport heat to the high-latitudes. As an explanation for equable climates, Brian Farrell presented this idea in 1990 and advocated that during equable climates, the Hadley Cells extended from the equator to the poles (Farrell, 1990).

What is consumptive and non consumptive water usage?

The consumptive and nonconsumptive classifications of water are important when assessing the quantity o£ water allocated. Water used consumptively diminishes the source and is not available for other uses; whereas nonconsumptive water use does not diminish the source or impair future water use. Consumptive Use of Surface and Ground Water Consumptive water use causes diminishment of the source at the point of appropriation. Definition: Diminishment is defined as to make smaller or less in quantity, quality, rate of flow, or availability. By-pass reach defined. A water use may be consumptive to a specific reach of a stream when water is diverted, used, and returned to the same source at a point downstream not in close proximity to the point of diversion. The stream reaches between the point of withdrawal and point of discharge is the by-pass reach. 2. Nonconsumptive Water Use, Surface Water Surface water use is nonconsumptive when there is no diversion from the water source or diminishment of the source. Additionally, when water is diverted and returned immediately to the source at the point of diversion following its use in the same quantity as diverted and meets water quality standards for the source, the water use is classified as nonconsumptive. Examples of this classification include the following: a. Water use in hydroelectric projects when the water is not diverted away from the natural confines of the river or stream channel. These hydroelectric projects are commonly called run-of-the-river projects. b. Water use in some beautification ponds and fish hatcheries when the outflow is returned to the point of diversion, i.e., there is no bypass reach in the system. The continuous use of water by such a facility does not result in diminishment of the source; inflow is equal to outflow. These facilities normally require water to fill or charge the system once a year. The water used to fill or hydraulically charge such a system is consumptive and does cause a diminishment of the source. Water use to fill these facilities will be allowed, subject to instream flows and existing rights, when water is available. Exception to 2.B. Water use can be classified as nonconsumptive when the water is returned to the same pool from which it is diverted and the pool's water elevation is not changed by the initial start-up and stopping of the diversion.

What is till agriculture and why is it practiced?

The practice of no-till farming is especially beneficial to Great Plains farmers because of its resistance to erosion. Crop residues left intact help both natural precipitation and irrigation water infiltrate the soil where it can be used.

What is the difference types of soil horizons and how do they differ?

The results of the soil-forming processes are reflected in the different horizons developed in asoil profile. The soil profile extends from the surface downward to materials that are little altered by the soil-forming processes. Most soils contain three major mineral horizons: A, B, and C. These major horizons may be further sub-divided by the use of numbers and letters that indicate important characteristics of the subdivided horizons. An example is the B2t horizon, which designates a layer within the B horizoncontaining clay translocated from the A horizon. Most soils that have not been disturbed by cultivation have a thin organic horizon on top of the mineral soil. This organic horizon is designated by the letter O. The A horizon is the surface mineral layer. That part of the A horizon having the largest accumulation of organic matter is called the A1 horizon. The A2 horizon is the layer of maximum leaching, or eluviation, of clay and iron. The A2 horizon of many soils in Centre County is brownish because of the oxidation of iron. The B horizon lies underneath the A horizon and is commonly called the subsoil. It is the horizon of maximum accumulation, or illuviation, of clay, iron, aluminum, or other compounds leached from the A horizon. In some soils the B horizon forms through alteration of material in place rather than by illuviation. The alteration may be the result of oxidation and reduction of iron or the weathering of minerals. The B horizon generally has blocky or prismatic structure. It normally is firmer and lighter colored than the Al horizon, but it is generally brighter colored than the C horizon. Together, the A and B horizons constitute the solum-the zone in which most of themineral and organic matter has been added, removed, transferred, or translocated through the soil-forming processes. The C horizon is below the A and B horizons of most soils. It consists of materials that were little altered by the soil-forming processes, though the materials may be modified by weathering. Below the C horizon in some soils is an R horizon of consolidated bedrock, such as limestone, shale, or sandstone. In a few soils the C horizon is lacking, and the R horizon is directly beneath the B horizon.

What is a soil profile?

The soil profile is one of the most important concepts in soil science. It is a key to understanding the processes that have taken in soil development and is the means of determining the types of soil that occur and is the basis for their classification.

What is the Blue Revolution?

The term "blue revolution" refers to the remarkable emergence of aquaculture as an important and highly productive agricultural activity. Aquaculture refers to all forms of active culturing of aquatic animals and plants, occurring in marine, brackish, or fresh waters.

What is the hydrologic cycle is and how does it works?

The water cycle is called the hydrologic cycle. In the hydrologic cycle, water from oceans, lakes, swamps, rivers, plants, and even you, can turn into water vapor. Water vapor condenses into millions of tiny droplets that form clouds. Clouds lose their water as rain or snow, which is called precipitation. It's energy in the form of light, and heat causes water to EVAPORATE from oceans, rivers, lakes and even puddles. "Evaporate" means it turns the water from a liquid to a gas, or "vapor." Warm air currents rising from the earth's surface lift this water vapor up into the atmosphere.

What is xeriscaping?

The word "xeriscape" is derived from the Greek "xeros," meaning dry, and "scape," a kind of view or scene. Together, xeriscaping is landscaping with slow-growing, drought-tolerant plants to conserve water and establish a waste-efficient landscape.

What is fertilizer?

To make plants grow faster, what you need to do is supply the elements that the plants need in readily available forms. That is the goal of fertilizer. Most fertilizers supply just nitrogen, phosphorus and potassium because the other chemicals are needed in much lower quantities and are generally available in most soils. Nitrogen, phosphorus and potassium availability is the big limit to growth. The numbers on a bag of fertilizer tell you the percentages of available nitrogen, phosphorus and potassium found in the bag. So 12-8-10 fertilizer has 12-percent nitrogen, 8-percent phosphorous and 10-percent potassium. In a 100-pound bag, therefore, 12 pounds is nitrogen, 8 pounds is phosphorous and 10 pounds is potassium. The other 70 pounds is known as ballast and has no value to the plants. So why don't people need fertilizer to grow? Because we get everything we need from the plants we eat or from the meat of animals that ate plants. Plants are factories that do all of the work to process the basic elements of life and make them available to us. To get more information on fertilizer and other related topics, check out the links on the next page.

How is top soil formed and what it is composed of?

Topsoil is the upper, outermost layer of soil, usually the top 2 inches (5.1 cm) to 8 inches (20 cm). It has the highest concentration of organic matter and microorganisms and is where most of the Earth's biological soil activity occurs. Four elements constitute the composition of soil. Those elements are mineral particles, organic matter, water, and air. The majority of the top soils' volume consists of 50 to 80 percent of these particles which form the skeletal structure of most soils. This composition allows the soil to sustain its own weight, and other internal matter such as water and overlying landscape. Organic matter, another important element, varies on quantity on different soils. This provokes positive and negative effects or reactions on the soil. The strength of soil structure decreases with the presence of organic matter, creating weak bearing capacities. Organic matter condenses and settles in different ways under certain conditions, such as roadbeds and foundations. The skeletal structure becomes affected once the soil is dewatered. The soil's volume substantially decreases. It decomposes and suffers wind erosion.[1]

Transpiration

Transpiration is the process by which moisture is carried through plants from roots to small pores on the underside of leaves, where it changes to vapor and is released to the atmosphere. Transpiration is essentially evaporation of water from plant leaves.May 3, 2016

What is transpiration?

Transpiration is the process of water movement through a plant and its evaporation from aerial parts, such as leaves, stems and flowers. Water is necessary for plants but only a small amount of water taken up by the roots is used for growth and metabolism.

Nutrient holding capacity

Water Holding Capacity. The water holding capacity of a soil is a very important agronomic characteristic. Soils that hold generous amounts of water are less subject to leaching losses of nutrients or soil applied pesticides.

Infiltration-runoff ratio

When precipitation hits the ground, it has two options depending on where it is in its story line. It may infiltrate the soil or continue across the land as runoff. Infiltration occurs when surface water enters the soil. This process is similar to pouring water onto a sponge. The sponge soaks up the water until it can hold no more. At this point, the soil becomes saturated, but the excess water has to go somewhere. When this happens we get overflow in the form of runoff, which is when surface water flows over land.

What is a rain shadow and how does it cause a desert?

ain shadow is a patch of land that has been forced to become a desert because mountain ranges blocked all plant-growing, rainy weather. On one side of the mountain, wet weather systems drop rain and snow. On the other side of the mountain—the rain shadow side—all that precipitation is blocked. In a rain shadow, it's warm and dry. On the other side of the mountain, it's wet and cool. Why is there a difference? When an air mass moves from a low elevation to a high elevation, it expands and cools. This cool air cannot hold moisture as well as warm air. Cool air forms clouds, which drop rain and snow, as it rises up a mountain. After the air mass crosses over the peak of the mountain and starts down the other side, the air warms up and the clouds dissipate. That means there is less rainfall. You'll often find rain shadows next to some of the world's most famous mountain ranges. Death Valley, a desert in the U.S. states of California and Nevada, is so hot and dry because it is in the rain shadow of the Sierra Nevada mountain range. The Tibetan Plateau, a rain shadow in Tibet, China, and India has the enormous Himalaya mountain range to thank for its dry climate.

What is trade winds and how do they relate to global air circulation?

http://earthguide.ucsd.edu/virtualmuseum/climatechange1/08_1.shtml

What is land subsidence and sink holes and salt water intrusion are and what type of problems do they cause?

https://books.google.com/books?id=hBntufCOxAsC&pg=PA286&lpg=PA286&dq=What+is+land+subsidence+and+sink+holes+and+salt+water+intrusion+are+and+what+type+of+problems+do+they+cause&source=bl&ots=ZUL4z5imGJ&sig=h8einrOLU-qAICh4phn1yBdbGCs&hl=en&sa=X&ved=0ahUKEwi_xZ6BjKjPAhVC7IMKHWBXDKoQ6AEIKTAE#v=onepage&q=What%20is%20land%20subsidence%20and%20sink%20holes%20and%20salt%20water%20intrusion%20are%20and%20what%20type%20of%20problems%20do%20they%20cause&f=false http://water.usgs.gov/edu/earthgwlandsubside.html

What is the difference between humus, topsoil, subsoil and parent material?

https://www.acs.org/content/dam/acsorg/education/outreach/2006-cced-spring-edition-dig-it.pdf

What is the difference between sand, silt and clay?

​ Sand Sand, by its comparative large size does not have a chemical valence (capability to interact with charge particles) therefore does not hold minerals in the soil. Water molecules find as well easily their way through sand and get away by the action of gravity. The advantage of sand is its permeability to plants roots which can develop without obstacles. The inconvenient of sand is its poor water and plants nutrients retention. When cultivating with a sandy soil a lot of organic matter needs to be present in the soil to store moisture and nutrients. CLAY Clay in agriculture Clay, on the opposite, is very closed in size to elementary charged particles and react with ionized minerals. Different types of clay have different capabilities to exchanges cations (read more about CEC and measures of fertility) in the soil, playing a role in plant nutrients storage and availability. Usually clays in soils which have been weathered intensely and seen high bacterial activity for long geological periods (e.g. in the tropics) have structures less prone to interacts with minerals. It is one of the reason soils have a lack of minerals in the tropics. These minerals not being held by clay have been washed away by intense rains. In this case organic matter or more precisely humus play the role of nutrients storage with a higher electrostatic capability to interact with minerals than clay. The density of organic matter although is located in the top soil and reduce quickly in lower layers. The greater volume of clay compensate with the reduced capacity to hold nutrients. Plants with deep roots and symbiosis with fungus allow to access this reserve of nutrients in the subsoil. Clay in building and waterproofing Clay expand when in contact with water and shrink when getting dry. This particularity impact the different techniques of clay building. Mixing sand and clay using water create a solid aggregate when drying. Sand can be compared to stone and clay to mortar in this mixture. The flexible expanding and self sealing properties of bentonite make this clay suitable for pond waterproofing. Other techniques using gley (organic material transformed by anaerobic reaction) are a less expensive alternative to bentonite. Silt Silt is a sediment material with an intermediate size between sand and clay. Carried by water during flood it forms a fertile deposit on valleys floor. Silt is easily compacted. Loam Loam is a mixture of clay, sand and silt and benefits from the qualities of these 3 different textures, favoring water retention, air circulation, drainage and fertility. Humus Humus is a highly complex substance still not fully understood. It is a stable and uniformly dark, spongy and amorphous material which come from the mechanical degradation of organic matter. Humus is fertile and gather all properties suitable for optimal plant growth. It is formed by complex chemical compounds, of plant, animal and microbial origin SOURCE :http://ecotrancoso.com/html/clay... 31.8k Views · View Upvotes · Answer requested by

What are the different types of soil classification and how do they work?

← Soil Facts: Basic Information on Soil You Need to KnowGrowing and Gardening in Sandy Soil → 5 Different Soil Types - Know Your Soil Type Posted on 7 April 2011 by Leineriza Share soil types Last time, we discussed basic soil facts that you need to know before you started digging around in your garden. This time, we're going to look at different soil types and how to determine the kind of soil that'll be host to your plants. There are 5 different soil types that gardeners and growers usually work with. All five is a combination of just three types of weathered rock particles that make up the soil: sand, silt, and clay. How these three particles are combined defines your soil's type—how it feels to the touch, how it holds water, and how it's managed, among other things. 1. Soil Type: Sandy Sandy soil has the largest particles among the different soil types. It's dry and gritty to the touch, and because the particles have huge spaces between them, it can't hold on to water. Water drains rapidly, straight through to places where the roots, particularly those of seedlings, cannot reach. Plants don't have a chance of using the nutrients in sandy soil more efficiently as they're swiftly carried away by the runoff. The upside to sandy soil is that it's light to work with and warms much more quickly in the spring. Testing what type of soil you're working with involves moistening the soil and rolling it into a ball to check the predominating soil particle. When you roll the slightly wet sandy soil in your palms, no ball should be formed and it crumbles through your fingers easily. 2. Soil Type: Silty Silty soil has much smaller particles than sandy soil so it's smooth to the touch. When moistened, it's soapy slick. When you roll it between your fingers, dirt is left on your skin. Silty soil retains water longer, but it can't hold on to as much nutrients as you'd want it to though it's fairly fertile. Due to its moisture-retentive quality, silty soil is cold and drains poorly. Silty soil can also easily compact, so avoid trampling on it when working your garden. It can become poorly aerated, too. 3. Soil Type: Clay Clay soil has the smallest particles among the three so it has good water storage qualities. It's sticky to the touch when wet, but smooth when dry. Due to the tiny size of its particles and its tendency to settle together, little air passes through its spaces. Because it's also slower to drain, it has a tighter hold on plant nutrients. Clay soil is thus rich in plant food for better growth. Clay soil is cold and in the spring, takes time to warm since the water within also has to warm up. The downside is that clay soil could be very heavy to work with when it gets dry. Especially during the summer months, it could turn hard and compact, making it difficult to turn. (When clay soil is worked while it's too wet though, it's prone to damage). If moistened soil feels sticky, rolls up easily, and forms into a ball or sausage-like shape, then you've got yourself clay. 4. Soil Type: Peaty Peaty soil is dark brown or black in color, soft, easily compressed due to its high water content, and rich in organic matter. Peat soil started forming over 9,000 years ago, with the rapid melting of glaciers. This rapid melt drowned plants quickly and died in the process. Their decay was so slow underwater that it led to the accumulation of organic area in a concentrated spot. Although peat soil tends to be heavily saturated with water, once drained, it turns into a good growing medium. In the summer though, peat could be very dry and become a fire hazard. (I kid you not—peat is the precursor of coal.) The most desirable quality of peat soil, however, is in its ability to hold water in during the dry months and its capacity to protect the roots from damage during very wet months. Peat contains acidic water, but growers use it to regulate soil chemistry or pH levels as well as an agent of disease control for the soil. When wet peat soil is rolled, you won't form a ball. It's spongy to the touch and when squeezed, water could be forced out. 5. Soil Type: Saline Soil The soil in extremely dry regions is usually brackish because of its high salt content. Known as saline soil, it can cause damage to and stall plant growth, impede germination, and cause difficulties in irrigation. The salinity is due to the buildup of soluble salts in the rhizosphere—high salt contents prevent water uptake by plants, leading to drought stress. It's easy enough to test if you have saline soil. You'll probably see a white layer coating the surface of the soil, your plants are growing poorly, and they're suffering from leaf tip burn, especially on young leaves. The Ideal Soil Type: Loam The type of soil that gardens and gardeners love is loamy soil. It contains a balance of all three soil materials—silt, sand and clay—plus humus. It has a higher pH and calcium levels because of its previous organic matter content. Loam is dark in color and is mealy—soft, dry and crumbly—in your hands. It has a tight hold on water and plant food but it drains well, and air moves freely between soil particles down to the roots. The feel test for loam yields a smooth, partly gritty, partly sticky ball that crumbles easily. Although loamy soil is the ideal material to work with, don't despair if you don't have it in your garden. That's because soil will always favor one particles size over the two others. Then again, there are many ways to condition your soil—adding beneficial soil inoculants, covering your soil with compost, or simply spraying leaves and soil with compost tea. One Last Soil Typing Trick If you really want to know what soil type you're working with but don't want to get dirty, fill a smallish jar with soil sampling from your garden. Shake vigorously and let the soil settle overnight. Next day, you'll see distinct soil layers. Sand stays at the bottom, clay at the top and silt in between. Their percentages will be your clue on your soil type.