Fertilizers, ammonium based

Bodelier PEE, Roslev P, Henckel T, Frenzel P. 2000. Stimulation by ammonium-based fertilizers of methane oxidation in soil around rice roots. Nature 403 421-424. 

FOLLOW-UP PROBLEM 3.3 Ammonium nitrate is a common fertilizer. Agronomists base the effectiveness of fertilizers on their nitrogen content. 

Ammonia volatilization is recognized as the major process by which nitrogen fertilizers are lost from paddy fields, especially when urea or other ammonium-based fertilizers are surface applied to the water column. In tropical climates, high water temperatures associated with algal activity in the water column are conducive to enhance volatilization of added fertilizers. Urea, a common fertilizer for rice in Asia, is rapidly hydrolyzed within the week after application to submerged soils. Ammonia originating from the hydrolyzed urea accumulates in floodwater, and the peak concentration of ammonia in the floodwater of tropical rice fields typically occurs within 1-5 days after urea... 

Methane emissions from crop fields (notably rice paddy fields) are increased by the application of ammonium-based fertilizers these emissions contribute... 

Barisic, D., Lulic, S. andMiletic, P. (1992). Radium and uranium in phosphate fertilizers and their impact on the radioactivity of waters. Water Research, 26(5) 607-611. Bodelier, Paul, L.E., Peter Roslev, Thilo Henckel and Peter Frenzel (1999). Stimulation by ammonium-based fertilizers of methane oxidation in soil around rice roots. Nature, 403(6768) 421-424. 

Nitrogen fertilizers are based on the Haber process for producing ammonia from nitrogen and hydrogen. Although this is a very energy-intensive process it is well established, and full benefit has been taken of the economy of scale effect (see section 4.7, Volume I). The ammonia is then converted into ammonium salts and nitrates ... 

Complex fertilizers containing much sulfate sulfur possess increased agrochemical activity. Production of these fertilizers is based on neutralizing a mixture of phosphoric and sulfuric acids by ammonium and obtaining... 

About one-third of the fixed N was released as ammonia by acidic or alkaline hydrolysis, and hydroxylamine was also detected after acid hydrolysis. In most soils, the microbial oxidation of nitrite ion to nitrate is faster than the production of nitrite from ammonium. Even so, high application rates of ammonia or ammonium based fertilizers can lead to zones with locally-high pH values and accumulation... 

In the case of winter-sown cereals, there are a number of practical steps which can be taken to reduce losses. Early establishment of the crop will provide sufficient root growth to reduce nitrate leaching and this may be achieved by more careful timing and placement of fertilizer and possibly by the use of an ammonium based fertilizer. Unfortunately, the farmer is faced with the problem of having to work over a very short time period when weather conditions may be unsuitable and so prevent him from optimising all the operations required. 

A number of processes based upon the absorption of sulfur dioxide in aqueous solutions of ammonia have been proposed, and several have been developed to commercial or advanced pilot-plant operations. The processes differ primarily in the method of removing the sulfur dioxide from the ammonia-containing solution. Techniques used include steam or inoct-gas stripping, oxidation to sulfate, reduction to elemental sulfur, and displacemmit by a stronger acid. Three processes do not remove the sulfur dioxide from the ammonia-containing solution, but rather produce ammonium-based fertilizer. 

Ammonia from coal gasification has been used for fertilizer production at Sasol since the beginning of operations in 1955. In 1964 a dedicated coal-based ammonia synthesis plant was brought on stream. This plant has now been deactivated, and is being replaced with a new faciUty with three times the production capacity. Nitric acid is produced by oxidation and is converted with additional ammonia into ammonium nitrate fertilizers. The products are marketed either as a Hquid or in a soHd form known as Limestone Ammonium Nitrate. Also, two types of explosives are produced from ammonium nitrate. The first is a mixture of fuel oil and porous ammonium nitrate granules. The second type is produced by emulsifying small droplets of ammonium nitrate solution in oil. 

Some commonly used primary nutrient fertilizers are incidentally also rich sources of calcium. Ordinary superphosphate contains monocalcium phosphate and gypsum in amounts equivalent to all of the calcium originally present in the phosphate rock. Triple superphosphate contains soluble monocalcium phosphate equivalent to essentially all the P2 5 product. Other fertilizers rich in calcium are calcium nitrate [10124-37-5] calcium ammonium nitrate [39368-85-9] and calcium cyanamide [156-62-7]. The popular ammonium phosphate-based fertilizers are essentially devoid of calcium, but, in view of the natural calcium content of soils, this does not appear to be a problem. 

Nutrient release patterns vary with the amount of coating appHed and the substrate used. Coating weights vary from 10 to 20%. Typically, commercial products are blends of different coating weights. Coated substrates kiclude, but are not limited to, urea, potassium sulfate, and ammonium nitrate-based N—P—K fertilizers. 

Chisso-Asahi Fertilizer Company, Ltd. This company utilizes thermoplastic resins, such as polyolefins, poly(vinyhdene chloride), and copolymers, as their coating materials. The coatings are dissolved in fast-drying chlorinated hydrocarbon solvents and are appHed to a variety of substrates including urea, diammonium phosphate [7783-28-0] potassium sulfate [7778-80-3], potassium chloride [7447-40-7], and ammonium nitrate/potassium sulfate-based N—P—K fertilizers. 

Ammonium nitrate based products manufactured chemically for use as fertilizers which 1000 t... 

Ammonium nitrate based products manufactured chemically for use as fertilizers which comply with Council Directive 80/876/EEC and compound fertilizers where the nitrogen content derived from the ammonium nitrate >28 >[Pg.9]

The methods of analysis for phosphate solubility are not absolute, but empirical that is, they are based on practical experience. For example, the neutral ammonium citrate method is favoured in the USA because it has received over 100 years of study and experimentation, and provides an index correlating the laboratory results with the fertilizing value of water-insoluble phosphates under the conditions prevailing in the principal farming regions of the country. The particular solvent is therefore not an attempt to accurately reproduce the properties of the soil solution in the immediate vicinity of the... 

The single largest use of ammonia is its direct apphcation as fertdizer, and in the manufacture of ammonium fertilizers that have increased world food production dramatically. Such ammonia-based fertilizers are now the primary source of nitrogen in farm soils. Ammonia also is used in the manufacture of nitric acid, synthetic fibers, plastics, explosives and miscellaneous ammonium salts. Liquid ammonia is used as a solvent for many inorganic reactions in non-aqueous phase. Other apphcations include synthesis of amines and imines as a fluid for supercritical fluid extraction and chromatography and as a reference standard in i N-NMR. 

Ammonia-based chemicals appear to have some advantages over sodium systems. They are less costly, and regeneration by conventional means is possible, with the byproduct, ammonium sulfate, a marketable commodity for fertilizer. 

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