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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-ins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methylene Diurea
Methylene diurea (MDU) is the organic compound with the formula CH2(NHC(O)NH2)2. It is a white water-soluble solid. The compound is formed by the condensation reaction, condensation of formaldehyde with urea. Methylene diurea is the substrate for the enzyme methylenediurea deaminase. Applications MDU is an intermediate in the production of urea-formaldehyde resins. Together with dimethylene triurea, MDU is a component of some controlled-release fertilizers.{{Ullmann, doi= 10.1002/14356007.n10_n01 , title= Fertilizers, 2. Types , year=2009 , last1=Dittmar , first1=Heinrich , last2=Drach , first2=Manfred , last3=Vosskamp , first3=Ralf , last4=Trenkel , first4=Martin E. , last5=Gutser , first5=Reinhold , last6=Steffens , first6=Günter References [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seed Ball
Seed balls, also known as earth balls or , consist of seeds rolled within a ball of clay and other matter to assist germination. They are then thrown into vacant lots and over fences as a form of guerilla gardening. Matter such as humus and compost are often placed around the seeds to provide microbial inoculants. Cotton-fibres or liquefied paper are sometimes added to further protect the clay ball in particularly harsh habitats. An ancient technique, it was re-discovered by Japanese natural farming pioneer Masanobu Fukuoka. Development of technique The technique for creating seed balls was rediscovered by Japanese natural farming pioneer Masanobu Fukuoka. The technique was also used, for instance, in ancient Egypt to repair farms after the annual spring flooding of the Nile. Masanobu Fukuoka developed his technique during the period of the Second World War, while working in a Japanese government lab as a plant scientist on the mountainous island of Shikoku. He wanted to find a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urea
Urea, also called carbamide (because it is a diamide of carbonic acid), is an organic compound with chemical formula . This amide has two Amine, amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest amide of carbamic acid. Urea serves an important role in the cellular metabolism of nitrogen-containing compounds by animals and is the main nitrogen-containing substance in the urine of mammals. ''Urea'' is Neo-Latin, , , itself from Proto-Indo-European ''*h₂worsom''. It is a colorless, odorless solid, highly soluble in water, and practically non-toxic ( is 15 g/kg for rats). Dissolved in water, it is neither acidic nor base (chemistry), alkaline. The body uses it in many processes, most notably metabolic waste#Nitrogen wastes, nitrogen excretion. The liver forms it by combining two ammonia molecules () with a carbon dioxide () molecule in the urea cycle. Urea is widely used in fertilizers as a source of nitrogen (N) and is an important ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isobutylidenediurea
Isobutylidenediurea (abbreviated IBDU) is an organic compound with the formula (CH3)2CHCH2. It is a derivative of urea (OC(NH2)2), which itself is highly soluble in water, but IBDU is not. It functions as a controlled-release fertiliser owing to its low solubility, which limits the rate of its hydrolysis to urea, which is a fast-acting fertiliser. It is produced by the condensation reaction of isobutyraldehyde and two equivalents of urea: : (CH3)2CHCHO + 2 OC(NH2)2 → (CH3)2CHCH2 + H2O The controlled-release process is the reverse of the above reaction, which only occurs after the IBDU dissolves. Related materials A number of CRF's have been developed based on urea. Related to IBDU is crotonylidene diurea (Crotodur). Simpler are various urea-formaldehyde materials such as ureaform, which consists of methylene diurea Methylene diurea (MDU) is the organic compound with the formula CH2(NHC(O)NH2)2. It is a white water-soluble solid. The compound is formed by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urease
Ureases (), functionally, belong to the superfamily of amidohydrolases and phosphotriesterases. Ureases are found in numerous Bacteria, Archaea, fungi, algae, plants, and some invertebrates. Ureases are nickel-containing metalloenzymes of high molecular weight. Ureases are distinct from Urecases are important in degrading avian faecal matter, which is rich in uric acid, the breakdown product of which is urea, which is then degraded by urease as described here. These enzymes catalyze the hydrolysis of urea into carbon dioxide and ammonia: : (NH2)2CO + H2O CO2 + 2NH3 The hydrolysis of urea occurs in two stages. In the first stage, ammonia and carbamic acid are produced. The carbamate spontaneously and rapidly hydrolyzes to ammonia and carbonic acid. Urease activity increases the pH of its environment as ammonia is produced, which is basic. History Urease activity was first identified in 1876 by Frédéric Alphonse Musculus as a soluble ferment. In 1926, James B. Sumner ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrification
''Nitrification'' is the biological oxidation of ammonia to nitrate via the intermediary nitrite. Nitrification is an important step in the nitrogen cycle in soil. The process of complete nitrification may occur through separate organisms or entirely within one organism, as in comammox bacteria. The transformation of ammonia to nitrite is usually the rate limiting step of nitrification. Nitrification is an aerobic process performed by small groups of autotrophic bacteria and archaea. Microbiology Ammonia oxidation The process of nitrification begins with the first stage of ammonia oxidation, where ammonia (NH3) or ammonium (NH4+) get converted into nitrite (NO2−). This first stage is sometimes known as nitritation. It is performed by two groups of organisms, ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). Ammonia-Oxidizing Bacteria Ammonia-Oxidizing Bacteria (AOB) are typically Gram-negative bacteria and belong to Betaproteobacteria and Gammaproteob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Permeability (earth Sciences)
In fluid mechanics, materials science and Earth sciences, the permeability of porous media (often, a rock or soil) is a measure of the ability for fluids (gas or liquid) to flow through the media; it is commonly symbolized as ''k''. Fluids can more easily flow through a material with high permeability than one with low permeability. The permeability of a medium is related to the '' porosity'', but also to the shapes of the pores in the medium and their level of connectedness. Fluid flows can also be influenced in different lithological settings by brittle deformation of rocks in fault zones; the mechanisms by which this occurs are the subject of fault zone hydrogeology. Permeability is also affected by the pressure inside a material. The SI unit for permeability is the square metre (m2). A practical unit for permeability is the '' darcy'' (d), or more commonly the ''millidarcy'' (md) The name honors the French Engineer Henry Darcy who first described the flow of wat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soluble
In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution. The extent of the solubility of a substance in a specific solvent is generally measured as the concentration of the solute in a saturated solution, one in which no more solute can be dissolved. At this point, the two substances are said to be at the solubility equilibrium. For some solutes and solvents, there may be no such limit, in which case the two substances are said to be " miscible in all proportions" (or just "miscible"). The solute can be a solid, a liquid, or a gas, while the solvent is usually solid or liquid. Both may be pure substances, or may themselves be solutions. Gases are always miscible in all proportions, except in very extreme situations,J. de Swaan Arons and G. A. M. Diepen (1966): "Gas—Gas Equilibria". ''Journal of Chemical Physics'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBDU
Isobutylidenediurea (abbreviated IBDU) is an organic compound with the formula (CH3)2CHCH2. It is a derivative of urea (OC(NH2)2), which itself is highly soluble in water, but IBDU is not. It functions as a controlled-release fertiliser owing to its low solubility, which limits the rate of its hydrolysis to urea, which is a fast-acting fertiliser. It is produced by the condensation reaction of isobutyraldehyde and two equivalents of urea: : (CH3)2CHCHO + 2 OC(NH2)2 → (CH3)2CHCH2 + H2O The controlled-release process is the reverse of the above reaction, which only occurs after the IBDU dissolves. Related materials A number of CRF's have been developed based on urea. Related to IBDU is crotonylidene diurea (Crotodur). Simpler are various urea-formaldehyde materials such as ureaform, which consists of methylene diurea and dimethylene triurea Dimethylene triurea (DMTU) is the organic compound with the formula (H2NC(O)NHCH2NH)2CO. It is a white water-soluble solid. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crotonylidene Diurea
Crotonylidene diurea (CDU) is an organic compound formed by the condensation of crotonaldehyde with two equivalents of urea. It is a white, water-soluble solid. CDU is a component of some 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 per ...s.{{Ullmann, doi= 10.1002/14356007.n10_n01 , title= Fertilizers, 2. Types , year=2009 , last1=Dittmar , first1=Heinrich , last2=Drach , first2=Manfred , last3=Vosskamp , first3=Ralf , last4=Trenkel , first4=Martin E. , last5=Gutser , first5=Reinhold , last6=Steffens , first6=Günter References Fertilizers Horticulture Ureas Nitrogen heterocycles Heterocyclic compounds with 1 ring ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urease Inhibitor
Ureases (), functionally, belong to the superfamily of amidohydrolases and phosphotriesterases. Ureases are found in numerous Bacteria, Archaea, fungi, algae, plants, and some invertebrates. Ureases are nickel-containing metalloenzymes of high molecular weight. Ureases are distinct from Urecases are important in degrading avian faecal matter, which is rich in uric acid, the breakdown product of which is urea, which is then degraded by urease as described here. These enzymes catalyze the hydrolysis of urea into carbon dioxide and ammonia: : (NH2)2CO + H2O CO2 + 2NH3 The hydrolysis of urea occurs in two stages. In the first stage, ammonia and carbamic acid are produced. The carbamate spontaneously and rapidly hydrolyzes to ammonia and carbonic acid. Urease activity increases the pH of its environment as ammonia is produced, which is basic. History Urease activity was first identified in 1876 by Frédéric Alphonse Musculus as a soluble ferment. In 1926, James B. Sumner ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
