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Irrigation Scheduling
Irrigation scheduling is the process used by irrigation system managers to determine the correct frequency and duration of watering. The following factors may be taken into consideration: * Precipitation rate of the irrigation equipment – how quickly the water is applied, often expressed in inches or mm per hour. * Distribution uniformity of the irrigation system – how uniformly the water is applied, expressed as a percentage, the higher the number, the more uniform. * Soil infiltration rate – how quickly the water is absorbed by the soil, the rate of which also decreases as the soil becomes wetter, also often expressed in inches or mm per hour. * Slope (topography) of the land being irrigated as this affects how quickly runoff occurs, often expressed as a percentage, i.e. distance of fall divided by 100 units of horizontal distance (1 ft of fall per {{convert, 100, ft, m, abbr=on would be 1%). * Soil available water capacity, expressed in units of water per unit of soil, i. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irrigation
Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow Crop, crops, Landscape plant, landscape plants, and Lawn, lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has been developed by many cultures around the world. Irrigation helps to grow crops, maintain landscapes, and revegetation, revegetate disturbed soils in dry areas and during times of below-average rainfall. In addition to these uses, irrigation is also employed to protect crops from frost, suppress weed growth in grain fields, and prevent soil consolidation. It is also used to cool livestock, reduce dust, dispose of sewage, and support mining operations. Drainage, which involves the removal of surface and sub-surface water from a given location, is often studied in conjunction with irrigation. There are several methods of irrigation that differ in how water is supplied to plants. Surface irrigation, also known as gravity irri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rain Sensor
A rain sensor or ''rain switch'' is a switching device activated by rainfall. There are two main applications for rain sensors. The first is a water conservation device connected to an automatic irrigation system that causes the system to shut down in the event of rainfall. The second is a device used to protect the interior of an automobile from rain and to support the automatic mode of windscreen wipers. How Does a Rain Sensor Work? Operation The rain sensor works on the principle of total internal reflection. ... An infrared light beams at a 45-degree angle on a clear area of the windshield is reflected and it is sensed by thesensor-inside the car. When it rains, the wet glass causes the light to scatter and lesser amount of light gets reflected back to the sensor An additional application in professional satellite communications antennas is to trigger a rain blower on the aperture of the antenna feed, to remove water droplets from the mylar cover that keeps pressurized ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irrigation
Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow Crop, crops, Landscape plant, landscape plants, and Lawn, lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has been developed by many cultures around the world. Irrigation helps to grow crops, maintain landscapes, and revegetation, revegetate disturbed soils in dry areas and during times of below-average rainfall. In addition to these uses, irrigation is also employed to protect crops from frost, suppress weed growth in grain fields, and prevent soil consolidation. It is also used to cool livestock, reduce dust, dispose of sewage, and support mining operations. Drainage, which involves the removal of surface and sub-surface water from a given location, is often studied in conjunction with irrigation. There are several methods of irrigation that differ in how water is supplied to plants. Surface irrigation, also known as gravity irri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BAITSSS
BAITSSS (Backward-Averaged Iterative Two-Source Surface temperature and energy balance Solution) is biophysical Evapotranspiration (ET) computer model that determines water use, primarily in agriculture landscape, using remote sensing-based information. It was developed and refined by Ramesh Dhungel and the water resources group at University of Idaho's Kimberly Research and Extension Center since 2010. It has been used in different areas in the United States including Southern Idaho, Northern California, northwest Kansas, Texas, and Arizona. History of development BAITSSS originated from the research of Ramesh Dhungel, a graduate student at the University of Idaho, who joined a project called "Producing and integrating time series of gridded evapotranspiration for irrigation management, hydrology and remote sensing applications" under professor Richard G. Allen. In 2012, the initial version of landscape model was developed using the Python IDLE environment using NARR weather ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time Domain Reflectometer
A time-domain reflectometer (TDR) is an electronic instrument used to determine the characteristics of electrical lines by observing reflected waveforms. It can be used to characterize and locate faults in metallic cables (for example, twisted pair wire or coaxial cable). It can also be used to locate discontinuities in a connector, printed circuit board, or any other electrical path. Description A TDR measures reflections along a conductor. In order to measure those reflections, the TDR will transmit an incident signal onto the conductor and listen for its reflections. If the conductor is of a uniform impedance and is properly terminated, then there will be no reflections and the remaining incident signal will be absorbed at the far-end by the termination. Instead, if there are impedance variations, then some of the incident signal will be reflected back to the source. A TDR is similar in principle to radar. The impedance of the discontinuity can be determined from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nonlimiting Water Range
The non-limiting water range (NLWR) represents the range of water content in the soil where limitations to plant growth (such as water potential, air-filled porosity, or soil strength) are minimal. John Letey (1985) from UC Riverside introduced the NLWR concept in an attempt to integrate several physical properties associated with plant or root growth to refine the concept of available water capacity. Alvaro Pires da Silva, Bev Kay. and Ed Perfect (University of Guelph, Ontario) (1994) refined the concept and termed it ''least limiting water range'' (LLWR). The upper limit (wet end) of LLWR is determined not only at water content at field capacity (FC), but also the capability of providing adequate aeration for plant roots (usually taken as a minimum air filled porosity of 10%). The upper limit is then defined as: min q . Rather than air-filled porosity at 10%, LaoSheng Wu from UC Riverside proposed moisture content where Oxygen gas diffusion rate ODR value of 0.2 micro-g/cm2/mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neutron Probe
A neutron probe is a device used to measure the quantity of water present in soil. A typical neutron probe contains a pellet of americium-241 and beryllium. The alpha particles emitted by the decay of the americium collide with the light beryllium nuclei, producing fast neutrons. When these fast neutrons collide with hydrogen nuclei present in the soil being studied, they lose much of their energy. The detection of slow neutrons returning to the probe allows an estimate of the amount of hydrogen present. Since water contains two atoms of hydrogen per molecule, this therefore gives a measure of soil moisture. See also *Frequency domain sensor *Time-domain reflectometer *Neutron detection Neutron detection is the effective detection of neutrons entering a well-positioned detector. There are two key aspects to effective neutron detection: hardware and software. Detection hardware refers to the kind of neutron detector used (the most ... References * : Google Translate: "Establish ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Irrigation In Viticulture
Irrigation in viticulture is the process of applying extra water in the cultivation of grapevines. It is considered both controversial and essential to wine production. In the physiology of the grapevine, the amount of available water affects photosynthesis and hence growth, as well as the development of grape berries. While climate and humidity play important roles, a typical grape vine needs 25-35 inches (635-890 millimeters) of water a year, occurring during the spring and summer months of the growing season, to avoid stress.T. Stevenson ''"The Sotheby's Wine Encyclopedia"'' p. 15 Dorling Kindersley 2005 A vine that does not receive the necessary amount of water will have its growth altered in a number of ways; some effects of water stress (particularly, smaller berry size and somewhat higher sugar content) are considered desirable by wine grape growers. In many Old World wine regions, natural rainfall is considered the only source for water that will still allow the viney ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Domain Sensor
{{Short description, Soil moisture content measuring instrument Frequency domain (FD) sensor is an instrument developed for measuring soil moisture content. The instrument has an oscillating circuit, the sensing part of the sensor is embedded in the soil, and the operating frequency will depend on the value of soil's dielectric constant. Types of sensors * ''Capacitance probe'', or fringe capacitance sensor. Capacitance probes use capacitance to measure the dielectric permittivity of the soil. The volume of water in the total volume of soil most heavily influences the dielectric permittivity of the soil because the dielectric constant of water (80) is much greater than the other constituents of the soil (mineral soil: 4, organic matter: 4, air: 1). Thus, when the amount of water changes in the soil, the probe will measure a change in capacitance (from the change in dielectric permittivity) that can be directly correlated with a change in water content. Circuitry inside some comme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tensiometer (soil Science)
A tensiometer in soil science is a measuring instrument used to determine the matric water potential (\Psi_m) ( soil moisture tension) in the vadose zone. This device typically consists of a glass or plastic tube with a porous ceramic cup and is filled with water. The top of the tube has either a built-in vacuum gauge or a rubber cap used with a portable ''puncture tensiometer'' instrument, which uses a hypodermic needle to measure the pressure inside the tensiometer. The tensiometer is buried in the soil, and a hand pump is used to pull a partial vacuum. As water is pulled out of the soil by plants and evaporation, the vacuum inside the tube increases. When the soil is wetted flow can also occur in the reverse direction: as water is added to the soil, the vacuum inside the tube pulls moisture from the soil and decreases. When the water pressure in the tensiometer is determined to be in equilibrium with the water pressure in the soil, the tensiometer gauge reading represents ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rainfall
Rain is water droplets that have condensed from atmospheric water vapor and then fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides water for hydroelectric power plants, crop irrigation, and suitable conditions for many types of ecosystems. The major cause of rain production is moisture moving along three-dimensional zones of temperature and moisture contrasts known as weather fronts. If enough moisture and upward motion is present, precipitation falls from convective clouds (those with strong upward vertical motion) such as cumulonimbus (thunder clouds) which can organize into narrow rainbands. In mountainous areas, heavy precipitation is possible where upslope flow is maximized within windward sides of the terrain at elevation which forces moist air to condense and fall out as rainfall along the sides of mountains. On the leeward side of mountains, desert climates can exi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distribution Uniformity
Distribution uniformity or DU in irrigation is a measure of how uniformly water is applied to the area being watered, normally expressed as percentage, and not to be confused with efficiency. The distribution uniformity is often calculated when performing an irrigation audit. The DU should not be confused with the coefficient of uniformity (CU) which is often preferred for describing the performance of overhead pressurized systems. The most common measure of DU is the low quarter DU expressed as DUlq, which is a measure of the average of the lowest quarter of samples, divided by the average of all samples expressed as percentage. The higher the DUlq, the more uniform the coverage of the area measured. If all samples are equal, the DUlq is 1.0 or 100%. There is no universal value of DUlq for satisfactory system performance. A value of >.80 or 80% is considered above average. Distribution uniformity may be helpful as a starting point for irrigation scheduling Irrigation schedul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
