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Coated Urea
Coated urea fertilizers are a group of controlled release fertilizers consisting of prills of urea coated in less-soluble chemicals such as sulfur, polymers, other products or a combination. These fertilizers mitigate some of the negative aspects of urea fertilization, such as fertilizer burn. The coatings release the urea either when penetrated by water, as with sulfur, or when broken down, as with polymers. Overview Urea is widely used as a nitrogen fertilizer. Its high solubility in water makes it useful for liquid application, and it has a much lower risk of causing fertilizer burn than other chemicals such as calcium cyanide or ammonium nitrate. However, the risk of fertilizer burn with urea can be unacceptably high in some situations, such as higher temperatures. The high water-solubility of urea can be disadvantageous in some cases as well. One particular technique to mitigate these disadvantages has been to encapsulate prills of urea with less-soluble chemicals. These c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fertilizer
A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from liming materials or other non-nutrient soil amendments. Many sources of fertilizer exist, both natural and industrially produced. For most modern agricultural practices, fertilization focuses on three main macro nutrients: nitrogen (N), phosphorus (P), and potassium (K) with occasional addition of supplements like rock flour for micronutrients. Farmers apply these fertilizers in a variety of ways: through dry or pelletized or liquid application processes, using large agricultural equipment or hand-tool methods. Historically fertilization came from natural or organic sources: compost, animal manure, human manure, harvested minerals, crop rotations and byproducts of human-nature industries (i.e. fish processing waste, or bloodmeal from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Wiley & Sons
John Wiley & Sons, Inc., commonly known as Wiley (), is an American multinational publishing company founded in 1807 that focuses on academic publishing and instructional materials. The company produces books, journals, and encyclopedias, in print and electronically, as well as online products and services, training materials, and educational materials for undergraduate, graduate, and continuing education students. History The company was established in 1807 when Charles Wiley opened a print shop in Manhattan. The company was the publisher of 19th century American literary figures like James Fenimore Cooper, Washington Irving, Herman Melville, and Edgar Allan Poe, as well as of legal, religious, and other non-fiction titles. The firm took its current name in 1865. Wiley later shifted its focus to scientific, technical, and engineering subject areas, abandoning its literary interests. Wiley's son John (born in Flatbush, New York, October 4, 1808; died in East Orange, New Je ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urea-formaldehyde
Urea-formaldehyde (UF), also known as urea-methanal, so named for its common synthesis pathway and overall structure, is a nontransparent thermosetting resin or polymer. It is produced from urea and formaldehyde. These resins are used in adhesives, plywood, particle board, medium-density fibreboard (MDF), and molded objects. UF and relate amino resins are a class of thermosetting resins of which urea-formaldehyde resins make up 80% produced worldwide. Examples of amino resins use include in automobile tires to improve the bonding of rubber to in paper for improving tear strength, in molding electrical devices, jar caps, etc. History UF was first synthesized in 1884 by Dr Hölzer, who was working with Bernhard Tollens, neither of whom realized that the urea and formaldehyde were polymerizing. In the following years a large number of authors worked on the structure of these resins. In 1896, Carl Goldschmidt investigated the reaction further. He also obtained an amorphous, almos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turf Management
Turf management or pitchcare describes the work needed to keep a sporting pitch ready for use. This article looks at the various types of sporting pitches and the type of challenges which they present. The skills needed vary considerably dependent upon the sport and whether or not artificial surfaces are used. Special sets of skills are also needed to care for either sand-based athletic fields or native soil fields. Tennis courts There are two main types of tennis court, grass and clay. The clay courts can then be divided into natural clay, hard courts and fast/dry courts. All tennis courts should ideally be a little west of true north to ensure minimum problems from sunlight. *Grass courts. Historically very popular, they are now slowly being replaced by clay courts which offer the opportunity of year-round usage and lower maintenance. The skills needed to maintain a grass court are considerable. Traditionally the court is split into the foundations and drainage, the soil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Labeling Of Fertilizer
Many countries have standardized the labeling of fertilizers to indicate their contents of major nutrients. The most common labeling convention, the NPK or N-P-K label, shows the amounts of the chemical elements nitrogen, phosphorus, and potassium. Common labeling conventions The NPK analysis label Fertilizers are usually labeled with three numbers, as in 18-20-10, indicating the relative content of the primary macronutrients nitrogen (N), phosphorus (P), and potassium (K), respectively. More precisely, the first number ("N value") is the percentage of elemental nitrogen by weight in the fertilizer; that is, the mass fraction of nitrogen times 100. The second number ("P value") is the percentage by weight of phosphorus pentoxide in a fertilizer with the same amount of phosphorus that gets all of its phosphorus from P2O5. The third number ("K value") is analogous, based on the equivalent content of potassium oxide . For example, a 15-13-20 fertilizer would contain 15% by w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Putting Green
A golf course is the grounds on which the sport of golf is played. It consists of a series of holes, each consisting of a tee box, a fairway, the rough and other hazards, and a green with a cylindrical hole in the ground, known as a "cup". The cup holds a flagstick, known as a "pin". A standard round of golf consists of 18 holes, and as such most courses contain 18 distinct holes; however, there are many 9-hole courses and some that have holes with shared fairways or greens. There are also courses with a non-standard number of holes, such as 12 or 14. The vast majority of golf courses have holes of varying length and difficulties that are assigned a standard score, known as par, that a proficient player should be able to achieve; this is usually three, four or five strokes. Par-3 courses consist of holes all of which have a par of three. Short courses have gained in popularity; these consist of mostly par 3 holes, but often have some short par 4 holes. Many older courses ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tennessee Valley Authority
The Tennessee Valley Authority (TVA) is a federally owned electric utility corporation in the United States. TVA's service area covers all of Tennessee, portions of Alabama, Mississippi, and Kentucky, and small areas of Georgia, North Carolina, and Virginia. While owned by the federal government, TVA receives no taxpayer funding and operates similarly to a private for-profit company. It is headquartered in Knoxville, Tennessee, and is the sixth largest power supplier and largest public utility in the country. The TVA was created by Congress in 1933 as part of President Franklin D. Roosevelt's New Deal. Its initial purpose was to provide navigation, flood control, electricity generation, fertilizer manufacturing, regional planning, and economic development to the Tennessee Valley, a region that had suffered from lack of infrastructure and poverty during the Great Depression, relative to the rest of the nation. TVA was envisioned both as a power supplier and a regional economi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Micropore
A microporous material is a material containing pores with diameters less than 2 nm. Examples of microporous materials include zeolites and metal-organic frameworks. Porous materials are classified into several kinds by their size. The recommendations of a panel convened by the International Union of Pure and Applied Chemistry (IUPAC) are: See page 1745. *Microporous materials have pore diameters of less than 2 nm. *Mesoporous materials have pore diameters between 2 nm and 50 nm. *Macroporous materials have pore diameters of greater than 50 nm. Micropores may be defined differently in other contexts. For example, in the context of porous aggregations such as soil, micropores are defined as cavities with sizes less than 30 μm. Uses in laboratories Microporous materials are often used in laboratory environments to facilitate contaminant-free exchange of gases. Mold spores, bacteria, and other airborne contaminants will become trapped, while gases are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonium Nitrate
Ammonium nitrate is a chemical compound with the chemical formula . It is a white crystalline salt consisting of ions of ammonium and nitrate. It is highly soluble in water and hygroscopic as a solid, although it does not form hydrates. It is predominantly used in agriculture as a high-nitrogen fertilizer.Karl-Heinz Zapp "Ammonium Compounds" in ''Ullmann's Encyclopedia of Industrial Chemistry'' 2012, Wiley-VCH, Weinheim. Global production was estimated at 21.6 million tonnes in 2017. Its other major use is as a component of explosive mixtures used in mining, quarrying, and civil construction. It is the major constituent of ANFO, a popular industrial explosive which accounts for 80% of explosives used in North America; similar formulations have been used in improvised explosive devices. Many countries are phasing out its use in consumer applications due to concerns over its potential for misuse. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Controlled Release Fertilizer
224px, Methylene diurea (MDU) is component of the most popular controlled-release fertilizers. A controlled-release fertiliser (CRF) is a granulated fertiliser that releases nutrients gradually into the soil (i.e., with a controlled release period). Controlled-release fertilizer is also known as controlled-availability fertilizer, delayed-release fertilizer, metered-release fertilizer, or slow-acting fertilizer. Usually CRF refers to nitrogen-based fertilizers. Slow- and controlled-release involve only 0.15% (562,000 tons) of the fertilizer market (1995). History Controlled-nitrogen-release technologies based on polymers derived from combining urea and formaldehyde were first produced in 1936 and commercialized in 1955. The early product had 60 percent of the total nitrogen cold-water-insoluble, and the unreacted (quick-release) less than 15%. Methylene ureas, e.g. methylene diurea, were commercialized in the 1960s and 1970s, having 25% and 60% of the nitrogen as cold-water-insolu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcium Cyanide
Calcium cyanide is the inorganic compound with the chemical formula, formula Ca(CN)2. It is the calcium Salt (chemistry), salt derived from hydrocyanic acid. It is a white solid, although the pure material is rarely encountered. It hydrolyses readily (even in Moisture, moist air) to release hydrogen cyanide and is very toxic. Preparation Solutions of calcium cyanide can be prepared by treating calcium hydroxide with hydrogen cyanide. Solid calcium cyanide is produced commercially by heating calcium cyanamide with sodium chloride. The reaction is incomplete. The product is only of 50% purity, other components being sodium cyanide, calcium cyanamide, and carbon. Because of the carbon impurity, the solid is black, hence material is often called black cyanide. Reactivity At temperatures around 600 °C, calcium cyanide converts to calcium cyanamide:"Production of Hydrocyanic Acid" ''United States Patent Office.'' 1933.(accessed April 22, 2012). :Ca(CN)2 → CaCN2 + C It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fertilizer Burn
Fertilizer burns occur when the use of too much fertilizer, the wrong type of fertilizer, or too little water with a fertilizer causes damage to a plant. Although fertilizer is used to help a plant grow by providing nutrients, too much will result in excess salt, nitrogen, or ammonia which have adverse effects on a plant. An excess of these nutrients can damage the plant's ability to photosynthesize and cellularly respire, causing visible burns. The intensity of burns determine the strategy for recovery. Background Fertilizers contain nutrients that increase plant growth by increasing the rate of photosynthesis (the process in which plants uptake water and nutrients to create sugar) and cellular respiration (the process in which carbon dioxide and sugar is broken down to be used as energy, releasing oxygen). Nutrients and water enter the plant through the plants’ root cell membranes (the barrier separating the inside of the root cells from the outside) via of osmosis (the movem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
