A Review Of Controlled Release Fertilizers Biology Essay

A brushup Of Controlled push solelyton Fertilizers Biology EssayIn general, plants must be supplied with alimentarys during the whole flora period. In horticulture this is achieved by applying right away fat-soluble fertiliser at a time to twice a week, for ensample. This human body of plant food masking is real labour-intensive and requires considerable specialist knowledge, so as to select the clear measure of exertion, appropriate condemnation of use and correct composition for the p articular plants to ensure optimum plant overlapion. With the use of dumb or controlled expel fertilisers the full mensuration of nourishings necessary for the whole vegetation period slew be utilise at the time of place or at the earliest stages of plant growth, in the form of a nutritive pool Also, closely half of the apply plant foods, depending on the order of application and ground condition, is alienated to the environment, which results in the contamination of water 1.This kind of environmental concerns of feeding crops with traditional plant foods has led to developing Slow Release Fertilizers (SRFs) or Controlled Release Fertilizers (CRFs). SRFs or CRFs atomic number 18 easy and safe to use. They invalidate risk of incorrect fertilizer application they be labour frugality and minimize alimental losses by pillageing or fixation.The estimate of producing SRFs was demonstrable from 1963 by encapsulation of fertilizers by get upes. afterwards that, these products exhaust been commercialized. at that place ar very much of SRF and CRF brands market leader in controlled release fertilizers is Scotts Professional with fundamental brands such(prenominal) as Osmocote Exact, Sierrablen and Osmoform. SunGro Company is a uniform producing controlled release fertilizers with brand ca-ca of Multicoate. AGLUKON is as well a nonher commercialized SRF product 2-4.Like stacks of scientific fields, factory farm industry has been everyplace shadowed by nanotechnology. Applications of nanotechnology in agriculture embarrasss agriculture crop improvement, nanobiotechnology analysis of gene expression and regulation acres management, plant disease diagnostics, efficient pesticides and fertilizers, water management, bio biddinging, post harvest technology, supervise the identity and quality of bucolic produce and precision agriculture5. Efficient pesticides and fertilizers in terms of Nano-composite base decompress release fertilizers atomic number 18 developing in current decades. Using nano ingredients as reinforcing or cementing constituent of polymer finishings has been the only peculiarity of nano particles which is apply in preparing sluggish release fertilizers 6,7.FertilizersFertilizers ar applied to blur to promote plant growth. They contain well-nigh beneficial nutrients including macronutrients and micronutrients. Macronutrients atomic number 18 normality, phosphorus, and green whi ch be added to frequentwealth in quantities from0.2% to 4.0% (on a dry matter load basis) and atomic number 18 more(prenominal) than prerequisite than micronutrients. Micronutrients atomic number 18 elements which are applied to s rock oil in much smaller amounts, ranging from 5 to 200 ppm, or little than 0.02% dry weigh. These elements could be southward (S), boron (B), copper (Cu), iron (Fe), atomic number 25 (Mn), molybdenum (Mo), zinc (Zn)8,9.2.2. Types of fertilizersFertilizers would be categorized from get rid ofset of universe and similarly from release properties points of view. All fertilizers could be organic fertilizer or unreal from source of being point of view. Organic fertilizers are naturally occurred including seaweed, worm casting, manure, slurry, peat, humic acid, guano and brassin. They provide slow up release of nutrient as they need farmings bacterium to be broken refine to needed elements. Also, they whitethorn improve the biodiversity of imperfection by supplying organic matters and micronutrients for organisms. Organic fertilizers are cheaper and safer than synthetic fertilizers 9,10.The important synthetic or mineral fertilizers are carbamide, ammonium sulphate, ammonium orthophosphate, phosphate rock, potassium chloride, super phosphates, calcium ammonium nit tell, potassium sulphate and NPK, PK and PK conf apply fertilizers. The most important drawbacks of synthetic fertilizer is their long term sustainability. Also, they are more expensive in contrast to organic fertilizers 10.Also, fertilizers crapper be categorized into customary and controlled release fertilizers from release properties points of view.Drawbacks of non- controlled release fertilizersOrdinary fertilizers leach to soil very quickly and most of them are not utilise by the plants. According to figures about 40-70% of nitrogen, 80-90% of phosphorous, and 50-70% of the applied normal fertilizer is lost to environment and cannot be employ by plants11. This rapid leaching volition cause burning of plants and growing in spurts. Also, the lost elements leave set up several(prenominal) serious problems for our environment. Eutrophication, Blue baby syndrome, soil acidification, persistent organic pollutants, heavy metal accumulation, atmospheric cause are environmental concerns of ordinary fertilizers. Another result of quick leaching of fertilizer is repeating the application of fertilizers which will increase the costs8,12,13.Slow or controlled release fertilizersSlow release fertilizers or controlled release fertilizers are coer in a kernel that enables a slow release time and eliminates need for constant binding and toweringer efficiency pasture than soluble fertilizers 14.The interest in these worldlys is for whiz or more of the following reasons Availability of nutrients during the hole growing-season reduced nutrient loss via leaching and run-off reduced cost and labor outlay in crop performance redu ced chemic and biological immobilization reactions in soil which cause plant unavailable forms reduction of rapid nitrification and nitrogen loss through with(predicate) ammonia volatilization and denitrification reduced seed or misuse from high local concentrations of salts reduced leaf burn from heavy place of come near-applied fertilizers better seasonal distribution of growth and better acclimatization in home or display environment improved storage and use of fertilizer materials15.Differences between slow and controlled release fertilizersAlthough there is no a special difference in general function of CRF and SRF, but it should be menti unmatchedd that they are manufactured by opposite materials and techniques with different properties. In slow release fertilizers elements are present in the fertilizers in a chemical form, which is not available to plants and they will be converted by physiochemical effects or microorganisms activities into nutrient forms in the soil. But in controlled release fertilizers elements are packed in coat granules and are released through the application program over a certain period of time. Also, in SRFs nutrients available period is touched by a lot of factors such as water contented of soil, Ph, temperature, microorganisms activity, aeration. However, the longevity of CRF depends on screening burdensomeness and temperature of soil. Only last mode is effective in changing pattern of nutrients release and a touch on covering thickness control nutrients release. In CRFs declared release time refers to soil temperature of 20-21 oC. Higher temperatures accelerate the element release and lower temperatures check it longer 4,16.SRFs are chemically brisk slow released. Some kinds of SRFs are Urea Aldehydes (UA) and Chelated Micronutrients(CM). Common persona of UAs is urea formaldehyde which is high nitrogen fertilizer. Starting release rate of UAs is high but it dies off slowly for 3 years. This kind of fertili zer depends on microorganisms to break it down for plant use. CMs are substances that hold firmly together iron, manganese, zinc, and copper. They slowly releases over a long period of time 17.2.4.2. Types of CRFs2.4.2.1. Sulfur Coated (SC) main(a) treat when is oxidized to its sulfate form would be one of the nutrients which is essential for slightly plants and is normally blended with other fertilizers. Using mho cultivation is also another way to provide reciprocal ohm simultaneously with do slow release properties for a core starchlike fertilizer. As the sulfur containing materials like polysulfides or lingosulfonate are brittle and also give a low making water of defects they are normally mixed with waxes or plasticizers. many an(prenominal) formulas are available for SCs. Their release time is generally 3-4 months. SDs are released by microorganisms 18-222.4.2.2. Wax cover (WC)One of the systems of reducing fertilizer release rate is dispersing granular fertilizers with molten wax and wherefore cooling the mixture under the liquescent point of the wax 23. Paraffin is one of the most used wax as a masking for fertilizers. Paraffinwax is a white, tasteless, odorless, waxy hale, with a typical resolve point between about 47 C and 64 24. Other types of waxes are synthetic oil based, pet sectionum or mineral waxes. Waxes are normally used by an additive or a tackifiere agent to make up a intelligent sealing properties 25,262.4.2.3. Polymer Coated (PC)Polymer-coat fertilizers (PCF) represent the most technically advanced controlled released fertilizers. They include a water-soluble fertilizer core and one or more than one seams of polymer. There are large varieties of polymers to coat the core fertilizer also the natural coverings shape could be the same one or different. In PC fertilizers release of nutrients will carry on by diffusion through a semi permeable polymer membrane. Water penetrates the finis and dissolves the core. Release rate can be controlled by varying the composition and thickness of the coating. In addition, pressure builds up can cause cracks to form, from which fertilizer passes into the soil 27, 28.2.5. Review of preparation systems of different polymer coat CRFs2.5.1. Sole Polymer coverOne type of polymer surface CRFs is the one which the fertilizer core which could be N, P, K OR NPK salmagundi, is just coated with one or more than one point of polymer coating. In this case the polymer could be solvent based or water-based. The application process starts with dissolving the polymer in a organic solvent or water. later on dissolving the coating will be sprayed onto the fertilizer in a coating drum or fluid bed 29. Bene habilitates of polymer coated CRFs are as follow uniform and defect free coating will surround fertilizer the coating will be very tough and durable which is resistant against mechanical breakdown they are biologically inactive so they will not breakdown by soil microbe s.In most cases except for degradable polymers release of fertilizers will be happen by diffusion through polymer coat rather than through defects. In some other coated fertilizers like sulfur coatings there should be a flaw in coating to make release of fertilizer.There are lots of examples for polymers which have been used in literatures as coating for fertilizers, some of them are as follow dicyclopentadien30,Urea and urethane based 31-36, epoxy glue based 37-39, polyvinylidene chloride-based latex29 carboxyl-carrying ethylene polymers40, perishable starch based41, urea formaldehyde42.However, polymer coated fertilizers have some week points. About solvent-based coatings apply large amount of organic solvents like toluene or xylene will lead to environmental concerns. These solvents are volatile and releasing them to environment makes some hazards for human health. Also, polymer coatings are more expensive than sulfur coatings the process and equipments are also more complex t han equipments used for other coatings.2.5.2. Sulfur-polymer coatedOne of most common coated fertilizers are the ones in which core fertilizer is covered by a layer of sulfur coating and a layer of polymer. The polymer layer can be primer or outer layer subject matter that sulfur layer in some searches has been the first layer and in some others the outer layer. SulfurUsing coating is a suggested mode to draw back drawbacks of sulfur coated CRFs. One of these drawbacks is very fast release of fertilizer in first few days after application. The other one is brittleness of sulfur coatings which may lead to some fractures during handling or storage and losing the fertilizer into soil. Another problem is that sulfur coatings have a high get up tension with water and cannot provide enough wetting for a good diffusion 19, 29, 38, 21.The most common method for applying the sulfur coating is spray. Molten sulfur mingled will be sprayed over a pre-polymer coated fertilizer granule 38, 43.2.5.3. Wax-polymer coatedThere are lots of researches foc use on making controlled release fertilizers utilise Wax-polymer coatings. Wax layer has common chord major benefits one is that they are applied over the polymer layer for change magnitude the fracture probability of coating and the other one is for decreasing the amount of polymer and emptying consuming more polymers to make the process cost effective. Also, they can eliminate imperfection of granules surface to make a good surface coating.Most common waxes which have been used in show of the art is C30 alpha-olefin and paraffin. Other petroleum products like lubricants and bitumen or natural products like canola oil, soybean oil, coconut oil and palm oil, also have been used.After warming the wax it will be applied by mixing with polymer coated fertilizer. Normally the polymer is thermoset to avoid any damages of polymer by the wax in its melting point. The wax normally should have drop melting point from 50 to 120C. Wax is normally about 0.2% to 10 % by weight of fertilizer 25, 38, 44, 45.2.5.4. Filler- polymer coatedAs mentioned before, despite lots of advantages of polymer coating to make slow release properties when such polymers are used as a sole coating material the ultimate product would be expensive as you have to consume large amount of polymer. Using mineral or organic fillers is one way to avoid using large amount of polymer. Also, in some researches fillers play the role of detackifier, to prevent adherence of coated granules to each other, and streng whenceing agent 46.Fillers may be used either as a mixture with polymer to make a nano-composite polymer 47 or as a separate layer. The most common method is snatch one in which the filler will be added and mixed with polymer coated granules before drying the granules. Most common used fillers are some very fine(less than 20 microns) inert inorganic materials like clay, diatomaceous earth, bentonite, kaolin, gypsum powder lime stone, talc, barium sulfate. Some other fillers like waste cellulosic materials also have used as filler in combination with polymer.47-512.6. Techniques coating applicationAccording to studies have been through with(p) encapsulation methods of fertilizers can be divided into three methods including in-situ, spray and mixing.2.6.1. In situThis method includes formation of fluid dispersion of the soluble fertilizer in a solvent and mixing the ready issue with monomers of a polymer. Polymerization will happen and depend on the method granules or particles of fertilizers will form.Ni et al 52 have developed a double-coated urea fertilizer. For preparation of poly (N-vinyl-pyrroli make) hydrogels containing urea (PCU), the monomer and a resolution of urea in N-vinyl-pyrrolidone were mixed together. The polymerization was carried out at 65-C for 3 h. The resulting samples were vacuum- alter, milled, screened and stored. After that first coating was dried sample and some amounts of ur ea were mixed with sodium alginate (SA) solution. Mixed solution was and then added drop orthogonal into 5% (w/w) CaCl2 aqueous solution and stirred constantly. The drops immediately turned into granules (about 4mm in diameter) because the SA in the drop was crosslinked by Ca2+ at once. The granules were filtered and dried in oven at 70- C. indeed the granules were added to ethylcellulose ethanol solution. Multiple EC coatings were prepared by immersion of the previously coated granules into the Ethylcellulose (EC) solution repeatedly. Thus, EC-coated urea granules with different coating thickness were obtained.Hanafi et al 53, have coated a compound fertilizer by polyvinyl chloride (PVC), polyacrylamide (PA), natural rubber (NR), and polylactic acid (PLA) using in situ method. For encapsulation of compound fertilizer with polyacrylamide the granules were added to the solution mixture of monomers. whence the polymerization reaction will start in existence of fertilizers. The th ickness of the coating layer on the compound fertilizer granules, determined by SEM, gave PVC compound coated fertilizer the highest value of 3.04 lm, and the lowest was obtained by PA (2.04 m). Variation in the characteristics of the polymers would be utilized in producing CR compound fertilizer that fit the requirements of growing plants.Hudson et al 38 used epoxy to coat the fertilizer. In this research the urea granules were charged to a pan and warmed to 95C. Then the hydrogenated tallaw amine, 2-amino ethyl peperazine and bisphenol A diglycidyl ether were mixed and were added to the granules meanwhile polymerization happened and prepared mixture was agitated till the fertilizer granules dried.2.6.2. Spray methodThis method is most common method for coating the fertilizer granules in state of the art. Usually, the solution of polymer in a suitable solvent is sprayed on the granule of fertilizer and then the granules are dried to remove the solvent through evaporation. The disc ussion is repeated as often as necessary until the desired coating percentage is reached.Lan et al 54 have used Chitosan and poly(acrylic acid-co-acrylamide) as biodegradable polymers to coat the NPK fertilizer. The NPK was compound fertilizer granules with about 2 mm in diameter. It was placed in a rotary drum and then the Chitson powder which was change state in epoxy-aceton solution was sprayed over the fertilizer. After drying the coating , Chitson coated granules were added to a flask equipped with a mechanical mixer. Carbon tetracholoride, polyethylene glycoloctyl phenyl ether, sorbite anhydride monostearic acid ester, solution of acrylic acid acrylamide , N,N- methylenebisacrylamide and ammonium persulfate was slowly added to the flask. After mixing the coated granules were dried in oven. This product with good controlled-release and water-retention capacity, being degradable in soil and environment-friendly, could be especially useful in agricultural and horticultural appl ications.Tomaszewska et al 55 have used spray technique for encapsulation of fertilizers. In order to improve the properties of coatings, the granules of previously coated fertilizer (wet method) were sprayed with a polymer solution or axenic solvent (N,N dimethylformamide). Concentration of the polymer in solutions used for nebulizer was in the range of 13-17 wt%. Measurements of thickness, porosity of prepared coatings and microphotographic observation of the coatings were taken.Ma et al 56 have developed a method for encapsulation of fertilizer with a egotism assembled coating. The fertilizer granules were heated in a rotary drum to 75C for 10 minutes. Then the self assembling amphiphilic molecules (N,N-bisaminoethyl eleostearate) were sprayed over the fertilizer. After 20 minutes aliphatic isocyanates were sprayed over fertilizer. This process was repeated once again. The fertilizer kept for drying in the 75C for 20 minutes.Dai et al 57, have developed a controlled release fe rtilizer using a water soluble resin as a coating. The granular compound fertilizer was coated in fluidized bed.Lan et al 58, prepared a double-coated slow-release NPK compound fertilizer with superabsorbent and water-retention properties (DSFSW), whose inner coating was chitosan (CTS), and the outer coating was crosslinked poly(acrylic acid)/diatomite-containing urea (PAADU). This prepared product not only has slow-release property but also could absorb a large amount of water and preserve the soil moisture at the same time. In addition, the outer coating (PAADU) could cherish the inner coating (CTS) from mechanical damage. These were significant advantages over the normal slow release or controlled-release fertilizers, which generally have only a slow-release property. The results indicated that the DSFSW could be found an application in agriculture and horticulture, especially in drought-prone regions where the availableness of water is insufficient. At first the outer coating co ntaining urea diatomite (PAADU) was prepared. The NPK compound fertilizer granule was placed into a rotary drum, and the Chitosan powder was stuck on the granules by means of epoxy dissolved in acetone. The adhesive was applied by spraying at regular time intervals. The process was terminate until compact and homogeneous coating formed on fertilizer granule. The coated granules were dried to a constant mass at room temperature for 6 h. Then the CTS-coated NPK compound fertilizer granules were obtained. CTS-coated NPK compound fertilizer granules were dipped in water and then were immediately placed on PAADU powder and shaken. In this manner, PAADU could adhere to the surface of CTS-coated NPK compound fertilizer and form the outer coating. The surface of the product was crosslinked by spraying methanol solution of epoxy chloropropane and then dried in a 70 C oven to obtain the terminal product, i.e., the double-coated slow-release NPK compound fertilizer with superabsorbent and w ater-retention.Hansen et al 36, encapsulate the granular fertilizer with the epoxy resin using spray method. In this research not coated fertilizer was placed in a rotating drum and pre heated to 250 F. A rapid drying solution of copolymers dicyclopentadiene and a modified vegetable oil were applied over fertilizer using spray in a cut back stream of resin. Simultaneously hot air was passed through drum. Next monomers of second resin including a mixture of epoxidized soybean oil and polyester curing agent were applied over prepared granules. The solvent was a mixture of xylene and Cellosolve acetate.Hansen et al 39 also have used the above mentioned method for encapsulation of fertilizer with polyurethane. First of all the preheated fertilizer was coated by a synthetic drying oil. After drying the coating for a few minutes fertilizer were dusted by clay. Then Urethane solution in xylene and Cellosolve acetate were applied using spray.2.6.3.Simple mixingIn this method granules are s imply mixed with the coating at its melting point or with a solution of polymer in a suitable solvent.Tomaszewska et al 59 used this method for coating the granular NPK fertilizer with polysulfone (PSF), cellulose acetate (CA) and polyacrylonitrile (PAN). The coating solutions were prepared by the dissolution of the solid polymer in adequate solvent. The NPK fertilizer was successively added to adequate polymer solution, and was covered by a thin layer of the solution. Subsequently, granules were dropped into water, where the gelation process takes place. The coated granules were removed from the rashness bath and then dried to a constant mass. The multiple coatings were prepared by immersion of the single coated fertilizer into adequate polymer solution, then into water and drying.Hon 47 has prepared the coated granules by mixing method. After melting the thermoplastic polymer by heating, the cellulosic additive has been added to melt resin. Then after allowing the temperature to drop, for avoiding the fertilizer damage, the granules or powder fertilizer has been mixed with the prepared mixture using a Brabender Mixer.Markusch et al60 just has mixed the fertilizer pellets with at first, a diluted polyol and then with a diluted isocyantae to make a polyurethane coating. Then the feretilizer were placed in oven for drying.2.7. Special equipment for application of polymer coatingTypical strong-arm method for encapsulating fertilizers are spray coating, spray drying, pan coating, rotary plow atomization. Special equipments for these methods are rotary drum, pan or ribbon or paddle mixer, fluidized. Fluidized bed and rotary drums are the most important equipments 87, 88Polymers used as coating for CRFsA broad range of polymers has been used in fertilizer coating. These polymers could be thermoset, thermoplastic or biodegradable.Some of common thermoset polymers are urethane resin, epoxy resin, alkyd resin, unsaturated polyester resin, phenol resin, urea resin, melamine resin, phenol resin, silicon resin. Among them, urethane resin urethane is very common used.36,61Thermoplastic resins are not very common used in art because of some problems. As mentioned before a very preferable method of applying polymers is spraying the dissolved polymer over granules. Either some of thermoplastic resins are not soluble in a solvent or make a very viscose solution which is not suitable for spraying. Polyolefine is used in art for coating the fertilizer granules 47,62.Biopolymers, dispose in bioactive environments, degrade by the enzymatic action of microorganisms such as bacteria, fungi, and algae and their polymer chains may also be broken down by non enzymatic processes such as chemical hydrolysis. Non-biodegradable polymers are not environmental friendly. Due to environmental concerns there are some trends of replacing non-bio with bio degradable polymers as coating material from 1970s. But it should be mentioned that they are expensive yet and not very cost effective. Also, in production process durability of polymer should be modify with release time of fertilizer.Among natural and synthetic biopolymers starch and cellulose based polymers, chitosan (a analoguepolysaccharide),poly lactic acid and poly(-caprolactone) due to low cost and abundance are some of used biopolymers in fertilizer industry41,52,58,63-692.5. Coating thicknessGenerally, polymer coatings are applied in a thickness which is suitable to make a desired controlled release property. Thickness could be related to characteristic of polymer and also it depends on existed porosity of polymer surface. If water vapor transmission rate of coating material is 0.01 to 20, coating thickness would be 1 to 100 microns. favourite(a) coating thickness is 1 to 50 microns. Coating process could be repeated more than one layer to get desired nutrient release 49.2.6. Investigation of release behavior of CRFsRelease mechanism for different coatings is different. Thick encapsul ated granules like sulfur coating will allow the nutrient to release when a flaw or rupture appears on the coating surface. In this case, rupture will happen because of permeation of water into coating and inside osmotic pressure. Also, biodegradable polymers will release nutrients while destroying by soil microbes activity. Polymer coatings or combination of different coatings will happen by diffusion of water through walls porosities. In this case release rate of can be controlled by the particle size of coated granules, thickness of coating and permeability of coating surface.Also, altering the chemical composition of fertilizer core and the coating will change permeability of coating means that even basic or acidic environment will change the permeability. In some researches when the coating has been starch-vinyl, increasing size of encapsulated granules has led to retardant down the nutrient release 70, 71.There are some cadence test methods for measurement of controlled rele ase properties. According To European sample the standard release time of N during 24 h should be 15%of total core nutrient. Also, release rate for 15 day should be 75% of total nutrients. Also American and Japanese standards say that the initial release shouldnt be more than 40% of total nutrient.According to European standards for measuring the release rate encapsulated fertilizer should be immersed in pure water at 25 C (room temperature) in incubated state 72, 73. For example Detrick et all43 have investigated the release behavior of their product by immersion of 20 g of encapsulated granules for 8 h in water. After filtration of solid they dried the solid. Evaporation of water was done at 100 C for 8 hours. Also, Ma et all 31 placed 14 g of granules in fit mesh holder into a jar with 300 ml water at 23 C and agitated ir by an orbital shaker. Then, the adequate water was taken for elemental analysis.. Locquenghien et al 40 for investigation the slow release effect of fertilize r some amounts of fertilizer were continuously extracted with water. For this finding the granules were arranged in layer in a cylindrical vessel field with water. Water was passed through this layer and its Nitrogen content was analyzed.2.8. mercenary CRFs in world and MalaysiaUrea-formaldehydes are oldest slow release products which were produced in 1936 and then were commercialized in 1970s. These products were known as Ureaform, Bluchip, Nitroform Methex and Nutralene. After that Tennessee Valley introduced sulfur coated urea technology in1960s.Polymer coated fertilizers were produced as early as 1970 in Japan. Most important commercialized polymer coated CRFs are Osmocote, Nutricote 74Osmocote CRFs are NPK granules coated by a thermoset copolymer of dicyclopentadiene and a glycerol ester (linseed oil) dissolved in an aliphatic hydrocarbon solvent. The Osmocote CRFs are normally used for ornamental horticulture production like greenhouses, nurseries , citrus , and strawberry production75.Nutricote prills are encapsulated by thermoplastic resins likeas polyolefins, polyvinylidene chloride. The process of Nuricote involves dissolving polymer in fast-dryingchlorinated hydrocarbon solvents and then applying the solution to a variety of nutrient substrates including urea, potassium sulfate, diammonium phosphate, ammonium nitrate and potassium chloride. Blendin the polymer with talc and ethylene-vinyl acetate has been done to obtain desired release rate76 Sierra, Lesco and polyon are some other commercialaized CRFs in the world.In Malaysia two brands named Greenfeed77 and KAMILA78 has developed slow release fertilizer. Greenfeed contains Zeolite which helps to release nutrients when it is in contact with soil. KAMILA is specially formulated for oil plantation industry.2.9. Tracing nano-technology features in fertilizer industryReviewing literature shows that researches which have used nano-technology features in fertilizer industry are very rare. The main ben efits of nanoparticles in these researches are using them as reservoir of fertilizer or as filler 79,80. unharmed nano-particles, have large surface areas and their reactivity is much more great than that of micrometer size materials. Also, their surfaces and interfaces provide an active substrate for physical, chemical, and biological reactions 80. twain published researches have done using nano-particles. One has used nano-clay as carrier of metal-urea complex urea intercalated clay without any coating has been developed as slow release fertilizer79. In other one, a nanocomposite of nano particle, fertilizer and polymer has been granulated and developed as slow release fertilizer. The production method involves mixing monomers, adding nano particle, which could be nano clay, nano bentonite, nano kaolin, polymerization and then granulating the mixture. In this research nano particle just work as good and effective filler 81. do polymer-nano-particle composites is something common in industries. Lots of researches have been done in this area, but researches around using nano-particle as reservoir for fertilizer have been done rarely. For more study here, we will review the researches have been done.2.9.1. Interc