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Dryland Salinity
Dryland salinity is a natural process for soil, just like other processes such as Soil_erosion#Wind_erosion, wind erosion. Salinity degrades land by an increase in soil salinity, soil salt concentration in the environment, watercourse or soil in irrigation, unirrigated landscapes, being in excess of normal soil salt concentrations in dryland regions. Overview Salinity refers to the movement and concentration of salt in the landscape and its associated detriment to land and water resources; dryland salinity refers to salinity in unirrigated landscapes. Salinity processes extend from local to regional scales and are driven by imbalances in the water budget that result, primarily, from agriculturally driven landscape change. There are two types of salinity: Types of salinity There are two types of salinity. Primary salinity (natural salinity) and secondary salinity (induced salinity). (Nrm.qld.gov.au, 2013) Primary salinity naturally occurs in arid and saline environments such as sal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CSIRO ScienceImage 4088 Dryland Salinity Causes Trees To Die And Induces Serious Hillslope Gully And Sheet Erosion At Base Of Mesa Landscape Just West Of Charters Towers Northern QLD
The Commonwealth Scientific and Industrial Research Organisation (CSIRO) is an Australian Government agency that is responsible for scientific research and its commercial and industrial applications. CSIRO works with leading organisations around the world. From its headquarters in Canberra, CSIRO maintains more than 50 sites across Australia as well as in France and the United States, employing over 6,500 people. Federally funded scientific research in Australia began in 1916 with the creation of the Advisory Council of Science and Industry. However, the council struggled due to insufficient funding. In 1926, research efforts were revitalised with the establishment of the Council for Scientific and Industrial Research (CSIR), which strengthened national science leadership and increased research funding. CSIR grew rapidly, achieving significant early successes. In 1949, legislative changes led to the renaming of the organisation as Commonwealth Scientific and Industrial Research ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Cycle
The water cycle (or hydrologic cycle or hydrological cycle) is a biogeochemical cycle that involves the continuous movement of water on, above and below the surface of the Earth across different reservoirs. The mass of water on Earth remains fairly constant over time. However, the partitioning of the water into the major reservoirs of ice, fresh water, Saline water, salt water and Atmosphere, atmospheric water is variable and depends on Climate, climatic variables. The water moves from one reservoir to another, such as from river to ocean, or from the ocean to the atmosphere due to a variety of physical and chemical processes. The processes that drive these movements, or Flux (biology), fluxes, are evaporation, transpiration, condensation, Precipitation (meteorology), precipitation, Sublimation (phase transition), sublimation, Infiltration (hydrology), infiltration, surface runoff, and subsurface flow. In doing so, the water goes through different phases: liquid, solid (ice) and W ... [...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 occurs two to three days after rain or irrigation in pervious soils of uniform structure and texture. The nominal 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 f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soil Health
Soil health is a state of a soil meeting its range of ecosystem functions as appropriate to its environment. In more colloquial terms, the health of soil arises from favorable interactions of all soil components (living and non-living) that belong together, as in microbiota, plants and animals. It is possible that a soil can be healthy in terms of ecosystem functioning but not necessarily serve crop production or human nutrition directly, hence the scientific debate on terms and measurements. Soil health testing is pursued as an assessment of this status but tends to be confined largely to agronomic objectives. Soil health depends on soil biodiversity (with a robust soil biology, soil biota), and it can be improved via soil management, especially by care to keep protective living covers on the soil and by natural (carbon-containing) soil amendments. Inorganic fertilizers do not necessarily damage soil health if they are not used in excess, and if they bring about a general improveme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vegetation
Vegetation is an assemblage of plants and the ground cover they provide. It is a general term, without specific reference to particular Taxon, taxa, life forms, structure, Spatial ecology, spatial extent, or any other specific Botany, botanical or geographic characteristics. It is broader than the term ''Flora (plants), flora'' which refers to species richness, species composition. Perhaps the closest synonym is ''plant community'', but "vegetation" can, and often does, refer to a wider range of spatial scales than that term does, including scales as large as the global. Primeval redwood forests, coastal mangrove stands, sphagnum bogs, desert soil crusts, Road verge, roadside weed patches, wheat fields, cultivated gardens and lawns; all are encompassed by the term "vegetation". The vegetation type is defined by characteristic dominant species, or a common aspect of the assemblage, such as an elevation range or environmental commonality. The contemporary use of "vegetation" app ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catchment
A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, the drainage divide, made up of a succession of elevated features, such as ridges and hills. A basin may consist of smaller basins that merge at river confluences, forming a hierarchical pattern. Other terms for a drainage basin are catchment area, catchment basin, drainage area, river basin, water basin, and impluvium. In North America, they are commonly called a watershed, though in other English-speaking places, " watershed" is used only in its original sense, that of the drainage divide line. A drainage basin's boundaries are determined by watershed delineation, a common task in environmental engineering and science. In a closed drainage basin, or endorheic basin, rather than flowing to the ocean, water converges toward the interior ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capillary Action
Capillary action (sometimes called capillarity, capillary motion, capillary rise, capillary effect, or wicking) is the process of a liquid flowing in a narrow space without the assistance of external forces like Gravitation, gravity. The effect can be seen in the drawing up of liquids between the hairs of a paint-brush, in a thin tube such as a Drinking straw, straw, in porous materials such as paper and plaster, in some non-porous materials such as clay and liquefied carbon fiber, or in a biological cell. It occurs because of intermolecular forces between the liquid and surrounding solid surfaces. If the diameter of the tube is sufficiently small, then the combination of surface tension (which is caused by Cohesion (chemistry), cohesion within the liquid) and Adhesion, adhesive forces between the liquid and container wall act to propel the liquid. Etymology Capillary comes from the Latin word capillaris, meaning "of or resembling hair". The meaning stems from the tiny, hairl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evapotranspiration
Evapotranspiration (ET) refers to the combined processes which move water from the Earth's surface (open water and ice surfaces, bare soil and vegetation) into the Atmosphere of Earth, atmosphere. It covers both water evaporation (movement of water to the air directly from soil, Canopy interception, canopies, and water bodies) and transpiration (evaporation that occurs through the stomata, or openings, in plant leaves). Evapotranspiration is an important part of the local water cycle and climate, and measurement of it plays a key role in water resource management Irrigation, agricultural irrigation. Definition ''Evapotranspiration'' is defined as: "The combined processes through which water is transferred to the atmosphere from open water and ice surfaces, bare soil and vegetation that make up the Earth’s surface." Evapotranspiration is a combination of evaporation and transpiration, measured in order to better understand crop water requirements, irrigation scheduling, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groundwater Discharge
Groundwater discharge is the volumetric flow rate of groundwater through an aquifer. Total groundwater discharge, as reported through a specified area, is similarly expressed as: :Q = \fracKA where :''Q'' is the total groundwater discharge ( 3·T−1 m3/s), :''K'' is the hydraulic conductivity of the aquifer ( ·T−1 m/s), :''dh/dl'' is the hydraulic gradient ( ·L−1 unitless), and :''A'' is the area which the groundwater is flowing through ( 2 m2) For example, this can be used to determine the flow rate of water flowing along a plane with known geometry. The discharge potential The discharge potential is a potential in groundwater mechanics which links the physical properties, hydraulic head, with a mathematical formulation for the energy as a function of position. The discharge potential, \Phi 3·T−1 is defined in such way that its gradient equals the discharge vector. Q_x = -\frac Q_y = -\frac Thus the hydraulic head may be calculated in terms of the discharge pote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Groundwater Recharge
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. Groundwater recharge also encompasses water moving away from the water table farther into the saturated zone. 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. The most common methods to estimate recharge rates are: chloride mass balance (CMB); soil physics methods; environmental and isotopic tracers; groundwater-level fluctuation methods; water balance (WB) methods (including groundwater models (GMs)); and the estimation of baseflow (BF) to rivers. Text was copied from this source, which is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soil Erosion
Soil erosion is the denudation or wearing away of the Topsoil, upper layer of soil. It is a form of soil degradation. This natural process is caused by the dynamic activity of erosive agents, that is, water, ice (glaciers), snow, Atmosphere of Earth, air (wind), plants, and animals (including humans). In accordance with these agents, erosion is sometimes divided into water erosion, glacial erosion, snow erosion, Aeolian erosion, wind (aeolian) erosion, Zoogenic erosion, zoogenic erosion and anthropogenic erosion such as tillage erosion. Soil erosion may be a slow process that continues relatively unnoticed, or it may occur at an alarming rate causing a serious loss of topsoil. The loss of soil from Agricultural land, farmland may be reflected in reduced crop production potential, lower surface water quality and damaged drainage networks. Soil erosion could also cause sinkholes. Human activities have increased by 10–50 times the rate at which erosion is occurring world-wide. Exc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discharge (hydrology)
In hydrology, discharge is the volumetric flow rate (volume per time, in units of m3/h or ft3/h) of a stream. It equals the product of average flow velocity (with dimension of length per time, in m/h or ft/h) and the cross-sectional area (in m2 or ft2). It includes any suspended solids (e.g. sediment), dissolved chemicals like (aq), or biologic material (e.g. diatoms) in addition to the water itself. Terms may vary between disciplines. For example, a fluvial hydrologist studying natural river systems may define discharge as streamflow, whereas an engineer operating a reservoir system may equate it with outflow, contrasted with inflow. Formulation A discharge is a measure of the quantity of any fluid flow over unit time. The quantity may be either volume or mass. Thus the water discharge of a tap (faucet) can be measured with a measuring jug and a stopwatch. Here the discharge might be 1 litre per 15 seconds, equivalent to 67 ml/second or 4 litres/minute. This is an average meas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
