Fertilizers, fluid

Solution Fertilizers. Fluid fertilizers in use today can be divided into two major categories (1) solutions, in which the plant food content is entirely in solution and (2) suspensions, in which the plant food content exceeds its solubility, and the excess is held in suspension, usually by addition of a suspending agent. The solution-type mixtures were the first to achieve commercial importance. Beginning about 1950, the practice of making... 

Physical Properties. The physical form and stabiUty of a fertilizer product is of an importance almost equal to that of its chemical content. Commercial fertilizers of importance include not only soHds, but also fluids, both solutions and suspensions, and even a gas (anhydrous ammonia). 

Physical requirements of fluid fertilizers include freedom from sediments, suitably low viscosity, low vapor pressure, and noncorrosivity with regard to available handling equipment. Using anhydrous ammonia, the chief physical concerns, are in the safety of handling under pressure and the minimizing of vapor loss during injection into the sod. 

These nitrogen solutions are used both for direct field appHcation and as a nitrogen ingredient in fluid mixed fertilizers. 

Nitrogen in Multinutrient Fertilizers. Single-nutrient nitrogen materials suppHed over 85% of the fertilizer nitrogen used in the United States during the year ended June 30, 1990. The remaining 15% was suppHed as multinutrient materials (Fig. 3). This included 9% as ammonium phosphate, 2% as cogranulated mixtures, and 3% as fluid mixtures. 

The routes by which mineral phosphates are processed into finished fertilizers are outlined in Eigure 7. World and U.S. trends in the types of products produced are shown in Eigures 8 and 9, respectively. Most notable in both instances is the large, steady increase in the importance of monoammonium and diammonium phosphates as finished phosphate fertilizers at the expense of ordinary superphosphate, and to some extent at the expense of triple superphosphate. In the United States, about 65% of the total phosphate appHed is now in the form of granular ammonium phosphates, and additional amounts of ammonium phosphates are appHed as integral parts of granulated mixtures and fluid fertilizers. 

Fig. 9. U.S. trends in types of phosphate fertilizers consumed, where (—) represents ammonium phosphates, cogranulated mixtures, and fluids (-)...

Fig. 20. U.S. market share for several types of mixed fertilizer, where (—) represents bulk blends (-) ammoniation—granulation and ( ) fluids.

Micronutrients in Fluid Fertilizers. In terms of homogeneity and even distribution, fluid fertilizers are probably the best micronuttient carriers. Fluid carriers of micronutrients usually are nitrogen solutions, clear Hquid mixtures, or suspensions. Some micronutrients, however, are appHed as simple water solutions or suspensions. FoHar micronuttient sprays often contain only the micronuttient material in water solution. 

Disodium Tetraborate Pentahydrate, Refined pentahydrate consumed in the Urhted States is used in insulation fiber glass, glass, fertilizers, and herbicides. Smaller amounts are used in antifreeze (see Antifreezes and deicing fluids), ceramic glazes, and cleaning agents. About 40% of the pentahydrate produced in the Urhted States is exported (101). A large-scale apphcation of this chemical is in the preparation of perborate bleaches. 

Chisso-Asahi uses a spouted bed process for the production of their coated materials (12). A 12,000 t/yr faciHty is located in Japan. The semicontinuous process consists of two batch fluid-bed coaters. A dilute polymer solution is prepared by dissolving 5% polymer and release controlling agent into a chlorinated hydrocarbon solvent such as trichloroethylene. The solution is metered into the spouted bed where it is appHed to the fertilizer core. Hot air, used to fluidize the granules, evaporates the solvent which is recovered and reintroduced into the process. Mineral talc, when used, is either slurried into the polymer solution or introduced into the fluidizing air. 

Scotts technology (17) uses fluid-bed (Wurster column) technology to apply polymeric coatings to a number of fertilizer substrates including urea, potassium nitrate, potassium sulfate, and monoammonium phosphate (MAP). The coating material is appHed as a water-borne latex onto the fluidized substrate. As the substrate is fluidized with warm air (40—50°C), water is driven off and the latex coalesces into a continuous film around the fertilizer particle. The particular latex compositions used have selected glass-transition and blocking temperatures, which enable quick removal of the water before the soluble fertilizer core dissolves. This obviates the need to use precoats prior to the latex appHcation. 

Continuous fluid-bed granulators are used in the fertilizer and detergent industries. For fertilizer apphcations, near-size grannies are recycled to control the granule size distribution. Dust is not recycled directly, but first remelted or slurried in the liquid feed. 

EEC Directive amending Directive 76/116/EEC in respect of fluid fertilizers... 

Cows eating grass containing organophosphate ester hydraulic fluid had difficulty producing milk for their young. We do not know if this will also occur in people. We do not know if organophosphate ester hydraulic fluids will cause birth defects, affect fertility, or cause cancer. 

Tricresyl phosphate (a complex mixture containing tri-o, Xn-m-, and tri-para-cresyl phosphate that is used in certain hydraulic fluids) and TOCP are demonstrated testicular toxicants in rodents (Carlton et al. 1987 Somkuti et al. 1987a, 1987b). Tricresyl phosphate also has been shown to impair in vivo fertility in rats and mice (Carlton et al. 1987 Chapin et al. 1988a). In addition, tricresyl phosphate-treated female rats displayed vacuolar cytoplasmic alteration of ovarian interstitial cells (Carlton et al. 1987 NTP 1994). Reproductive effects have also been seen after oral exposure to butylated triphenyl phosphate (Latendresse et al. 1994b). 

Growth at the level of the organism is an increase in cell number, cell mass, extracellular mass, fluid content and other components of the body that result in an increase of body mass. The mammalian body has very different growth phases with different functions. The pre-implantation embryo does not grow, but only divides, fuelled by materials that were deposited in the egg before fertilization. After implantation there is very rapid cell division which is tightly coupled to cell differentiation in the process of gastrulation — the creation of the different lineages... 

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