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Deep Water Culture
Deep water culture (DWC) is a hydroponic method of plant production by means of suspending the plant roots in a solution of nutrient-rich, oxygenated water. Also known as deep flow technique (DFT), floating raft technology (FRT), or raceway, this method uses a rectangular tank less than one foot deep filled with a nutrient-rich solution with plants floating in Styrofoam boards on top. This method of floating the boards on the nutrient solution creates a near friction-less conveyor belt of floating rafts. DWC, along with nutrient film technique (NFT), and aggregate culture, is considered to be one of the most common hydroponic systems used today. Typically, DWC is used to grow short-term, non-fruiting crops such as leafy greens and herbs. The large volume of water helps mitigate rapid changes in temperature, pH, electrical conductivity (EC), and nutrient solution composition. Hobby methods Deep water culture has also been used by hobby growers. Net pots, plastic pots with netting to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deep Water Culture
Deep water culture (DWC) is a hydroponic method of plant production by means of suspending the plant roots in a solution of nutrient-rich, oxygenated water. Also known as deep flow technique (DFT), floating raft technology (FRT), or raceway, this method uses a rectangular tank less than one foot deep filled with a nutrient-rich solution with plants floating in Styrofoam boards on top. This method of floating the boards on the nutrient solution creates a near friction-less conveyor belt of floating rafts. DWC, along with nutrient film technique (NFT), and aggregate culture, is considered to be one of the most common hydroponic systems used today. Typically, DWC is used to grow short-term, non-fruiting crops such as leafy greens and herbs. The large volume of water helps mitigate rapid changes in temperature, pH, electrical conductivity (EC), and nutrient solution composition. Hobby methods Deep water culture has also been used by hobby growers. Net pots, plastic pots with netting to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydroponic
Hydroponics is a type of horticulture and a subset of hydroculture which involves growing plants, usually crops or medicinal plants, without soil, by using water-based mineral nutrient solutions in aqueous solvents. Terrestrial or aquatic plants may grow with their roots exposed to the nutritious liquid or in addition, the roots may be mechanically supported by an inert medium such as perlite, gravel, or other substrates. Despite inert media, roots can cause changes of the rhizosphere pH and root exudates can affect rhizosphere biology and physiological balance of the nutrient solution by secondary metabolites. Transgenic plants grown hydroponically allow the release of pharmaceutical proteins as part of the root exudate into the hydroponic medium. The nutrients used in hydroponic systems can come from many different organic or inorganic sources, including fish excrement, duck manure, purchased chemical fertilizers, or artificial nutrient solutions. Plants are commonl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nutrient Film Technique
Nutrient film technique (NFT) is a hydroponic technique where in a very shallow stream of water containing all the dissolved nutrients required for plant growth is re-circulated past the bare roots of plants in a watertight gully, also known as channels. History NFT was pioneered in 1965 by Allen Cooper at the Glasshouse Crops Research institute in Littlehampton, England. In an ideal system, the depth of the recirculating stream is very shallow, little more than a film of water, hence the name 'nutrient film'. This ensures that the thick root mat which develops in the bottom of the channel receives adequate air exposure. Description A properly designed NFT system is based on using the right channel slope, the right flow rate, and the right channel length. The plant roots are exposed to adequate supplies of water, oxygen and nutrients. In earlier production systems, there was a conflict between the supply of these requirements, since excessive or deficient amounts of one result ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rockwool
Mineral wool is any fibrous material formed by spinning or drawing molten mineral or rock materials such as slag and ceramics. Applications of mineral wool include thermal insulation (as both structural insulation and pipe insulation), filtration, soundproofing, and hydroponic growth medium. Naming Mineral wool is also known as ''mineral fiber'', ''mineral cotton'', ''mineral fibre'', ''man-made mineral fibre'' (MMMF), and ''man-made vitreous fiber'' (MMVF). Specific mineral wool products are ''stone wool'' and ''slag wool''. Europe also includes glass wool which, together with ceramic fiber, are entirely artificial fibers that can be made into different shapes and are spiky to touch. History Slag wool was first made in 1840 in Wales by Edward Parry, "but no effort appears to have been made to confine the wool after production; consequently it floated about the works with the slightest breeze, and became so injurious to the men that the process had to be abandoned ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygenation (environmental)
Environmental oxygenation can be important to the sustainability of a particular ecosystem. Insufficient oxygen ( environmental hypoxia) may occur in bodies of water such as ponds and rivers, tending to suppress the presence of aerobic organisms such as fish. Deoxygenation increases the relative population of anaerobic organisms such as plants and some bacteria, resulting in fish kills and other adverse events. The net effect is to alter the balance of nature by increasing the concentration of anaerobic over aerobic species. Oxygenation by water aeration can be part of the environmental remediation of a usually stagnant body of water. For example, Bubbly Creek in Chicago, Illinois, was hypoxic (deficient in oxygen) due to its use as an open sewer by Chicago's meat packing industry but has been oxygenated by introducing compressed air into its waters, increasing the fish population. A similar technique has previously been used in the Thames. Dissolved oxygen (DO) is measured in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mineral Wool
Mineral wool is any fibrous material formed by spinning or drawing molten mineral or rock materials such as slag and ceramics. Applications of mineral wool include thermal insulation (as both structural insulation and pipe insulation), filtration, soundproofing, and hydroponic growth medium. Naming Mineral wool is also known as ''mineral fiber'', ''mineral cotton'', ''mineral fibre'', ''man-made mineral fibre'' (MMMF), and ''man-made vitreous fiber'' (MMVF). Specific mineral wool products are ''stone wool'' and ''slag wool''. Europe also includes glass wool which, together with ceramic fiber, are entirely artificial fibers that can be made into different shapes and are spiky to touch. History Slag wool was first made in 1840 in Wales by Edward Parry, "but no effort appears to have been made to confine the wool after production; consequently it floated about the works with the slightest breeze, and became so injurious to the men that the process had to be abandoned". ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Resistivity And Conductivity
Electrical resistivity (also called specific electrical resistance or volume resistivity) is a fundamental property of a material that measures how strongly it resists electric current. A low resistivity indicates a material that readily allows electric current. Resistivity is commonly represented by the Greek letter (rho). The SI unit of electrical resistivity is the ohm-meter (Ω⋅m). For example, if a solid cube of material has sheet contacts on two opposite faces, and the resistance between these contacts is , then the resistivity of the material is . Electrical conductivity or specific conductance is the reciprocal of electrical resistivity. It represents a material's ability to conduct electric current. It is commonly signified by the Greek letter ( sigma), but (kappa) (especially in electrical engineering) and (gamma) are sometimes used. The SI unit of electrical conductivity is siemens per metre (S/m). Resistivity and conductivity are intensi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conductivity Factor
The conductivity factor (CF) of dissolved salts in a given solution is a measurement of conductivity. Using the electrical conductivity between two electrodes in a water solution, the level of dissolved solids in that solution can be measured. Measurements can then be used to dose the solution with the necessary nutrients in the case of hydroponics. Conductivity measurements are also used in ecology and environmental sciences to assess the level of nutrients in lakes and rivers. For a discussion of conductivity in this context, see Total dissolved solids Total dissolved solids (TDS) is a measure of the dissolved combined content of all inorganic and organic substances present in a liquid in molecular, ionized, or micro-granular ( colloidal sol) suspended form. TDS concentrations are often report .... CF (conductivity factor) is basically EC multiplied by 10, and is used in some places because it eliminates the need for a decimal point, so an EC of 0.1 is equal to a CF of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foam
Foams are materials formed by trapping pockets of gas in a liquid or solid. A bath sponge and the head on a glass of beer are examples of foams. In most foams, the volume of gas is large, with thin films of liquid or solid separating the regions of gas. Soap foams are also known as suds. Solid foams can be closed-cell or open-cell. In closed-cell foam, the gas forms discrete pockets, each completely surrounded by the solid material. In open-cell foam, gas pockets connect to each other. A bath sponge is an example of an open-cell foam: water easily flows through the entire structure, displacing the air. A sleeping mat is an example of a closed-cell foam: gas pockets are sealed from each other so the mat cannot soak up water. Foams are examples of dispersed media. In general, gas is present, so it divides into gas bubbles of different sizes (i.e., the material is polydisperse)—separated by liquid regions that may form films, thinner and thinner when the liquid phase drain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kratky Method
The Kratky method is a passive hydroponic technique for growing plants suspended above a reservoir of nutrient-rich water. Because it is a non-circulating technique, no additional inputs of water or nutrients are needed after the original application, and no electricity, pumps, or water and oxygen circulation systems are required. The Kratky method has applications both for commercial food production and as a small-scale and low-maintenance technique for home growers. It has been described as "the simplest hydroponic system." Description Plants are placed in net cups filled with an inert growth medium such as rock wool, expanded clay aggregate, sphagnum moss, or coconut coir. The net cups are suspended above a reservoir of water containing essential nutrients in solution. Only the root tips are allowed to touch the surface of the reservoir. As the plant grows and depletes the water level, a gap of moist air will form and expand between the water surface and the base of the plan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horticulture
Horticulture is the branch of agriculture that deals with the art, science, technology, and business of plant cultivation. It includes the cultivation of fruits, vegetables, nuts, seeds, herbs, sprouts, mushrooms, algae, flowers, seaweeds and non-food crops such as grass and ornamental trees and plants. It also includes plant conservation, landscape restoration, landscape and garden design, construction, and maintenance, and arboriculture, ornamental trees and lawns. The study and practice of horticulture have been traced back thousands of years. Horticulture contributed to the transition from nomadic human communities to sedentary, or semi-sedentary, horticultural communities.von Hagen, V.W. (1957) The Ancient Sun Kingdoms Of The Americas. Ohio: The World Publishing Company Horticulture is divided into several categories which focus on the cultivation and processing of different types of plants and food items for specific purposes. In order to conserve the science of horticultur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
