Fertilizers, encapsulated

Jarosiewicz, A., and Tomaszewska, M. (2003). Controlled-release NPK fertilizer encapsulated by polymeric membranes,... 

Cyclopentadiene oligomers have been formed by vapor deposition of CPD on kaolin to afford a sorbant for removal of oil from water (71). They are also employed as coatings for controlling release rates of fertilizers (72). Thermal addition of sulfur to a mixture of DCPD and CPD oligomers has led to a number of beneficial appHcations such as waste water oil adsorbant powdery foams (73), plasticized backing for carpets and artificial turfs (74), and in modified sulfur cements for encapsulating low-level radioactive wastes (75). 

Liquid fertilizers, potassium orthophosphates in, 20 637 Liquid-film coefficient, 15 695 Liquid filtration, 11 322-323 Liquid flavor forms, 11 576-577 Liquid flow control, in variable-conductance heat pipes, 13 233 Liquid fluidization, 11 791-792 Liquid food ingredients, encapsulated,... 

Microencapsulation means the envelopment of liquid droplets or solid particles with natural or synthetic polymers.The encapsulation of a substance with a polymer membrane is undertaken for various reasons, for example, as protection against moisture, or to obtain delayed dissolution of fertilizers, herbicides, or drugs by microencapsulation with semipermeable membranes. 

For ecosystems, there is a concept of environmental services (e.g., soil function). Soil conservation provides a range of obvious benefits, including the preservation of land use and fertility, supporting the production of fibers, food, or biofuels. These services have widened over time to encapsulate benefits of carbon sequestration or biodiversity protection. It is relatively easy to place values on the productive capacity in the former examples. It is somewhat harder to find the value of the latter uses, but as the Stern report (Stem 2006) illustrated, it is by no means impossible to calculate the value of, say, an upland peat bog. 

Agglomeration and encapsulation of fine particles are encountered in several industrial sectors such as pharmaceuticals, detergents, fertilizers, and animal feedstocks. The volume throughput in these processes can vary enormously. Batch processing is suitable for pharmaceutical applications where the volume of production is quite low and product values are very high, while a continuous process is essential in other sectors where the volume throughput is very high. 

Microencapsulation is also of importance in agricultural applications. Encapsulation of fertilizers ensures their slow release into soil and more uniform feeding to plants. Microencapsulation allows one to coat the surface of seeds with various important substances, such as growth agents, pesticides, and fertilizers. 

S-G photo-biodegradable polyethylene is now being used in a different way to reduce the pollution of water courses by fertilisers. By encapsulating the fertiliser in porous photo-biodegradable capsules fertiliser release times can be achieved from 40 days to one year. Nitrogenous fertiliser based on this principle are manufactured by Chisso-Asahi Fertilizer Company of Japan and scientific studies by Kawai of Okayama University have shown (personal communication) that the empty polymer capsules biodegrade rapidly in soil. 

Encapsulation by granulation of particulate materials is a fundamental operation widely practiced in a variety of chemical industries including pharmaceuticals, food, fertilizer, cosmetics, biomedical, and nuclear. 

Microcapsules with permeable walls enable prolonged release of the active components into the environment, such as in the case of prolonged release drugs, perfumes, deodorants, repellents, etc., or immobilization with locally limited activity of micro-encapsulated substances. Examples of the latter include microencapsulated fertilizers and pesticides with locally limited release to reduce leaching into the ground water, or microencapsulated catalysts and enzymes for chemical and biotechnological processes. 

Kuvshinnikov, I. M., Z. A. Tikhonovich, N. N. Bogdanova, A. A. Alekseev, and O. V Bratashova. 1987. Elimination of Caking of Nitrogen-Phosphorus-Potassium Fertilizer by Encapsulation with Urea-Formaldehyde Resins, Khimicheskaya Promyshlennost, 19(2) 27-29,... 

EMBRYONIC STEM CELLS A fertilized egg divides to form two cells. This binary division process continues till amass of-150 cells is formed. This mass called blastocyst consists of two regions the outer shell and an inner cell mass encapsulated by the outer shell. It is possible to extract this inner cell mass. The extracted mass can be cultured to create stem cells. These stem cells are pluripotent, a term indicative of their multiple potencies for forming any cell type under the proper impulse. 

A more fundamental view is reflected in the second approach, however, where sol-gel encapsulation science is divided into sections related to molecular confinement studies, the use of sol-gel encapsulation as a synthetic intermediate, and the structural studies. The majority of the articles and ideas reviewed were published in 2000 and later. Earlier studies were only included if they represented a major breakthrough or bore a special significance to the field. Finally, although the following review describes applications grouped into certain sections, much of the material may bear relevance to other sections, and it is clear that the emergent science of sol-gel will only benefit from such cross-fertilization. 

Indeed examination of many soil bacteria in situ reveals them to be heavily encapsulated. The synthesis of bacterial polysaccharides appears crucial to the maintenance of soil structure and ultimately soil fertility. The coalescence of mineral particles to form aggregates and the resistance of such aggregates to stress is a measure of a soil s stability. Many soil bacteria are able to bind soil particles into aggregates, through the production of extracellular polysaccharides, or by charge interactions. Addition of Azoto-bacter chroococcum or Pseudomonas sp. promotes the stabilisation of sterilised silt loam soils. 

The indiscriminate use of such agricultural chemicals as pesticides, herbicides, and fertilizers is an important source of environmental pollution. A novel application of polymer-bound materials has been made in the controlled release of agricultural chemicals (Allan et al., 1973 Beasley and Collins, 1970 Shambu et al., 1976 Schacht et al., 1977, 1978 reviews of Neogi and Allan, 1974 Scher, 1977). When these chemicals are covalently bound to a polymer from which they can be slowly released into the environment, they not only check pollution but their duration of action is prolonged. The same effect can be obtained by encapsulation of the chemicals in polymeric beads from which they can be released slowly, e.g., 2,4-dichlorophenoxyacetic acid and 4-amino-3,5,6-trichloropicolinic acid have been used in polymer-bound form. 

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