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Physical Properties Of Soil
The physical properties of soil, in order of decreasing importance for ecosystem services such as crop production, are Soil texture, texture, Soil structure, structure, bulk density, Pore space in soil, porosity, consistency, temperature, colour and Soil resistivity, resistivity. Soil texture is determined by the relative proportion of the three kinds of soil mineral particles, called soil separates: sand, silt, and clay. At the next larger scale, soil structures called peds or more commonly ''soil aggregates'' are created from the soil separates when iron oxides, carbonates, clay, silica and humus, coat particles and cause them to adhere into larger, relatively stable secondary structures. Soil bulk density, when determined at standardized moisture conditions, is an estimate of soil compaction. Soil porosity consists of the void part of the soil volume and is occupied by gases or water. Soil consistency is the ability of soil materials to stick together. Soil temperature and colou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soil
Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former term specifically to displaced soil. Soil consists of a solid phase of minerals and organic matter (the soil matrix), as well as a porous phase that holds gases (the soil atmosphere) and water (the soil solution). Accordingly, soil is a three-state system of solids, liquids, and gases. Soil is a product of several factors: the influence of climate, relief (elevation, orientation, and slope of terrain), organisms, and the soil's parent materials (original minerals) interacting over time. It continually undergoes development by way of numerous physical, chemical and biological processes, which include weathering with associated erosion. Given its complexity and strong internal connectedness, soil ecologists regard soil as an ecosystem. Most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soil Compaction
In geotechnical engineering, soil compaction is the process in which stress applied to a soil causes densification as air is displaced from the pores between the soil grains. When stress is applied that causes densification due to water (or other liquid) being displaced from between the soil grains, then consolidation, not compaction, has occurred. Normally, compaction is the result of heavy machinery compressing the soil, but it can also occur due to the passage of, for example, animal feet. In soil science and agronomy, soil compaction is usually a combination of both engineering compaction and consolidation, so may occur due to a lack of water in the soil, the applied stress being internal suction due to water evaporation as well as due to passage of animal feet. Affected soils become less able to absorb rainfall, thus increasing runoff and erosion. Plants have difficulty in compacted soil because the mineral grains are pressed together, leaving little space for air and wate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Field Capacity
Field capacity is the amount of soil moisture or water content held in the soil after excess water has drained away and the rate of downward movement has decreased. This usually takes place 2–3 days after rain or irrigation in pervious soils of uniform structure and texture. The physical definition of field capacity (expressed symbolically as θfc) is the bulk water content retained in soil at −33 kPa (or −0.33 bar) of hydraulic head or suction pressure. The term originated from Israelsen and West and Frank Veihmeyer and Arthur Hendrickson. Veihmeyer and Hendrickson realized the limitation in this measurement and commented that it is ''affected by so many factors that, precisely, it is not a constant'' (for a particular soil), ''yet it does serve as a practical measure of soil water-holding capacity''. Field capacity improves on the concept of moisture equivalent by Lyman Briggs. Veihmeyer & Hendrickson proposed this concept as an attempt to improve water-use efficiency for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shrink–swell Capacity
The shrink–swell capacity of soils refers to the extent certain clay minerals will expand when wet and retract when dry. Soil with a high shrink–swell capacity is problematic and is known as shrink–swell soil, or expansive soil. The amount of certain clay minerals that are present, such as montmorillonite and smectite, directly affects the shrink-swell capacity of soil. This ability to drastically change volume can cause damage to existing structures, such as cracks in foundations or the walls of swimming pools. Description Due to the physical and chemical properties of some claysNagel, David. "Soil Science for Vegetable Producers." MSU: Coordinated Access to the Research and Extension System. 2001. Mississippi State U. 6 July 2008 http://msucares.com/pubs/publications/p1977.htm. (such as the Lias Group) large swelling occurs when water is absorbed. Conversely when the water dries up these clays contract (shrink). The presence of these clay minerals is what allows soils to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infiltration (hydrology)
Infiltration is the process by which water on the ground surface enters the soil. It is commonly used in both hydrology and soil sciences. The infiltration capacity is defined as the maximum rate of infiltration. It is most often measured in meters per day but can also be measured in other units of distance over time if necessary. The infiltration capacity decreases as the soil moisture content of soils surface layers increases. If the precipitation rate exceeds the infiltration rate, runoff will usually occur unless there is some physical barrier. Infiltrometers, permeameters and rainfall simulators are all devices that can be used to measure infiltration rates. Infiltration is caused by multiple factors including; gravity, capillary forces, adsorption and osmosis. Many soil characteristics can also play a role in determining the rate at which infiltration occurs. Factors that affect infiltration Precipitation Precipitation can impact infiltration in many ways. The am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kootenay National Park - Paint Pots 1
Kootenay, Kootenai, and Kutenai may refer to: Ethnic groups *The Kutenai, also known as the Ktunaxa, Kootenai, or Kootenay, an indigenous people of the United States and Canada ** Kutenai language, the traditional language of the Kutenai **Ktunaxa Nation, a First Nations government in British Columbia, Canada ** Kootenai Tribe of Idaho, a federally recognized tribe in Idaho, United States, ** Confederated Salish and Kootenai Tribes, a federally recognized tribe in Montana, United States Places Communities *Kootenai, Idaho, United States * Kootenay, British Columbia, Canada * Kootenay Bay, an unincorporated community in British Columbia, Canada * Kootenai County, Idaho, United States *Diocese of Kootenay, a diocese of the Ecclesiastical Province of British Columbia and the Yukon of the Anglican Church of Canada *List of electoral districts in the Kootenays, electoral districts in the Kootenays region of British Columbia ** Kootenay (electoral district), a former electoral distric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Collier Macmillan
Crowell-Collier Publishing Company was an American publisher that owned the popular magazines '' Collier's'', ''Woman's Home Companion'' and ''The American Magazine''. Crowell's subsidiary, P.F. Collier and Son, published ''Collier's Encyclopedia,'' the Harvard Classics, and general interest books. The company was founded by agricultural tool manufacturer P. P. Mast with a single magazine, ''Farm & Fireside (''later the ''Country Home'''')'' to sell farm tools and implements in 1877 in Springfield, Ohio. By 1881, Mast had relinquished control to John S. Crowell who expanded their company by purchasing ''Home Companion'' (later changing the name to ''Woman's Home Companion''). After P. P. Mast's death in 1898, Crowell obtained control of the company and established it as the Crowell Publishing Company. Crowell Publishing expanded their magazine holdings with ''The American Magazine'' in 1911 and the weekly '' Collier's'' in 1919. At one point Collier's weekly had over 1.25 mill ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iowa State University
Iowa State University of Science and Technology (Iowa State University, Iowa State, or ISU) is a public land-grant research university in Ames, Iowa. Founded in 1858 as the Iowa Agricultural College and Model Farm, Iowa State became one of the nation's first designated land-grant institution when the Iowa Legislature accepted the provisions of the 1862 Morrill Act on September 11, 1862, making Iowa the first state in the nation to do so. On July 4, 1959, the college was officially renamed Iowa State University of Science and Technology. Iowa State is classified among "R1: Doctoral Universities – Very high research activity". The university is home to the Ames Laboratory, one of ten national U.S. Department of Energy Office of Science research laboratories, the Biorenewables Research Laboratory, the Plant Sciences Institute, and various other research institutes. Iowa State is the second-largest university in the State of Iowa by undergraduate enrollment. The university's ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soil Water (retention)
Soils can process and hold considerable amounts of water. They can take in water, and will keep doing so until they are full, or until the rate at which they can transmit water into and through the pores is exceeded. Some of this water will steadily drain through the soil (via gravity) and end up in the waterways and streams, but much of it will be retained, despite the influence of gravity. Much of this retained water can be used by plants and other organisms, also contributing to land productivity and soil health. Soil water retention capacity Pores (the spaces that exist between soil particles) provide for the passage and/or retention of gasses and moisture within the soil profile. The soil's ability to retain water is strongly related to particle size; water molecules hold more tightly to the fine particles of a clay soil than to coarser particles of a sandy soil, so clays generally retain more water.Leeper, G.W. & Uren, N.C., 1993. ''Soil Science: An Introduction'', 5th edn. Me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aeration
Aeration (also called aerification or aeriation) is the Systems engineering process, process by which air is circulated through, mixed with or solvation, dissolved in a liquid or other substances that act as a fluid (such as soil). Aeration processes create additional surface area in the mixture, allowing greater chemical or suspension reactions. Aeration of liquids Methods Aeration of liquids (usually water) is achieved by: * passing air through the liquid by means of the Venturi tube, Aeration Turbine, aeration turbines or compressed air which can be combined with diffuser(s) air stone(s), as well as fine bubble diffusers, coarse bubble diffusers or linear aeration tubing. Ceramics are suitable for this purpose, often involving dispersion of fine air or gas bubbles through the porous ceramic into a liquid. The smaller the bubbles, the more gas is exposed to the liquid increasing the gas transfer efficiency. Diffusers or spargers can also be designed into the system to cause turbu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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