Fertilisers Nitrogenous

V. SaucheUi, Fertiliser Nitrogen, Reinhold Publishing Corp., New York, 1969, p. 133. 

Sodium nitrate is used as a fertiliser and in a number of industrial processes. In the period from 1880—1910 it accounted for 60% of the world fertiliser nitrogen production. In the 1990s sodium nitrate accounts for 0.1% of the world fertiliser nitrogen production, and is used for some specific crops and soil conditions. This decline has resulted from an enormous growth in fertiliser manufacture and an increased use of less expensive nitrogen fertilisers (qv) produced from synthetic ammonia (qv), such as urea (qv), ammonium nitrate, ammonium phosphates, ammonium sulfate, and ammonia itself (see Ammonium compounds). The commercial production of synthetic ammonia began in 1921, soon after the end of World War I. The main industrial market for sodium nitrate was at first the manufacture of nitric acid (qv) and explosives (see Explosives and propellants). As of the mid-1990s sodium nitrate was used in the production of some explosives and in a number of industrial areas. 

In addition to a continued increase in the number of use patents in these fields, a new use of xanthates as inhibitors of fertiliser nitrogen transformation in soil has been reported, as well as the use of certain metal xanthates as color developers for image-recording materials (113,114) (see Fertilizers Color photography). For several years, sodium isopropyl xanthate was used as an intermediate in the manufacture of saccharin (see... 

Foulkes, M.J., Sylvester-Bradley, R. and Scott, R.K. 1998. Evidence for differences between winter wheat cultivars in acquisition of soil mineral nitrogen and uptake and utilisation of applied fertiliser nitrogen. Journal of Agricultural Science 130 29-44. 

The form of fertiliser nitrogen can affect the pH of the rhizosphere. Ammonium nitrogen has been shown to decrease the pH in the vicinity of roots of wheat whereas fertilisation with nitrate nitrogen increased the rhizosphere pH compared with the pH of the bulk soil. Differences of up to 1.2 units occurred under field conditions (Smiley, 1974). Hauter and Mengel (1988) used Sb electrodes to measure soil pH at the root surface of red clover. Lowest pH values were found at the root tips and in a sandy soil the pH at the surface of root laterals was about one unit lower than in the bulk soil. 

This describes the practice of growing a green crop with the primary objective of absorbing soil nitrogen over the winter months to prevent its leaching. This can benefit the environment as well as saving on expensive fertiliser nitrogen. 

Table 20.4 Fertiliser nitrogen timing recommendations for grazing swards and for swards cut for silage...

Ammonium compounds are very important fertilisers. Nitrogen is removed from the soil as nitrates are absorbed through the roots when plants are growing. When crops are harvested by farmers the nitrogen is not replaced, as the plants do not die naturally and rot back into the soil. So farmers use ammonium compounds to replace this nitrogen in the soil. Common ammonium salts used in fertilisers include ammonium chloride, NH Cl, ammonium nitrate, NH NO, ammonium phosphate, (NH )3P0 > and ammonium sulfate, (NH )2SO. ... 

Uses of ammonia and ammonium compounds. Most of the ammonia produced is used in the manufaeture of nitrogenous fertilisers such as ammonium sulphate. Other uses include nitric acid and synthetic fibre and plastic manufacture. 

Bloremedia.tlon. Cmde oil and refined products are readily biodegradable under aerobic conditions, but they are only incomplete foods siace they lack any significant nitrogen, phosphoms, and essential trace elements. Bioremediation strategies for removing large quantities of hydrocarbon must therefore iaclude the addition of fertilisers to provide these elements la a bioavailable form. 

Markets. Industrial use of ammonia varies according to region. Eor example, industrial usage represents 20% of the ammonia production in the United States and Western Europe, 10% in the USSR, 1—10% in Asia, and 5% in Latin America and North Africa (79). Fertiliser ammonia consumed domestically in most countries is converted to straight or compound fertilisers such as urea, ammonium nitrate, diammonium phosphate, and various grades of mixed fertilisers. However, almost 29% of ammonia nitrogen in the United States is consumed as direct appHcation material. The use of nitrogen solution such as urea and ammonium nitrate (UAN) has also become popular in the United States and the USSR. 

Calcium cyanamide (lime nitrogen) has been used as a fertiliser (6). It hydrolyses ia moist soil to produce ammonia ... 

J. T. Hays, "Controlled Release Nitrogen Fertilisers," ManualFert. Proc. (1987). 

In North America, calcium cyanamide is no longer used as fertiliser, but it has limited use in special agricultural appHcations for defoHants, fungicides, herbicides, and as a weed killer. The primary industrial use is as a chemical intermediate for the manufacture of calcium cyanide, hydrogen cyanamide solution, and dicyandiamide. Calcium cyanamide is also used to add nitrogen to steel. 

K. A. Smith and J. R. M. Arah, Losses of Nitrogen by Denitrification and Emissions of Nitrogen Oxides from Soils, The Fertiliser Soeiety, 1990, Proeeedings No. 299. 

Nitrogen compounds These also arise from both natural and synthetic sources. Thus ammonia is formed in the atmosphere during electrical storms, but increases in the ammonium ion concentration in rainfall over Europe in recent years are attributed to increased use of artiflcial fertilisers. Ammonium compounds in solution may increase the wettability of a metaland the action of ammonia and its compounds in causing season cracking , a type of stress-corrosion cracking of cold-worked brass, is well documented. 

In nitrogenous fertiliser solutions of the NH4NOJ—NHj —HjO type corrosion of steel can be prevented by 500 p.p.m. of sulphur-containing inhibitors, e.g. mercaptobenzothiazole, thiourea and ammonium thiocyanate. However, these inhibitors are not so effective where most of the NHj is replaced by urea. For these solutions phosphate inhibitors such as (NH4>2HP04 and polyphosphates were more effective... 

In hospitals, chemical analysis is widely used to assist in the diagnosis of illness and in monitoring the condition of patients. In farming, the nature and level of fertiliser application is based upon information obtained by analysis of the soil to determine its content of the essential plant nutrients, nitrogen, phosphorus and potassium, and of the trace elements which are necessary for healthy plant growth. 

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