Nitrogen fertilisation

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. 

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. 

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

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 the conventional herd, concentrate use has decreased and stocking rate has increased, presumably because of the increased use of nitrogen fertiliser (Table 3.2). Wilkinson (1984) presents data to... 

The answer to the absence of fast-acting nitrogen fertilisers, with arable crops and grassland, has been threefold first, to make much greater use of farmyard manure, and to make sure that it is properly stored and not allowed either to be washed down the drains or to volatilise into the air second, to make much greater use of the legume for its power of nitrogen fixation, particularly white and red clover... 

Cai Z, Xing G, Yan X, Xu H, Tsuruta H, Yagi K, Minami K. Methane and nitrous oxide emissions from rice paddy fields as affected by nitrogen fertilisers and water management. Plant Soil. 1997 196 7-14. 

Wang Z, DeLaune RD, Lindau CW, Patrick WH. Methane production from anaerobic soil amended with rice straw and nitrogen fertilisers. Fert. Res. 1992 33 115-121. 

Because nitrogenous fertilisers promote plant growth, ammonia solution (which is alkaline) is neutralised by dilute nitric acid to form ammonium nitrate. 

Fig. 5.4 Long-term impact of reduced nitrogen fertilisation on the yield of whole crop cereals and SRCs on a sandy soil in Germany (relative yield related to the yield of an application rate of 150 kg N ha-1). The reduction of the N application rate by 50% results in a mean relative yield loss of -10% after 15 years for rye and triticale. Non-fertilisation cause significantly higher losses. By contrast, the relative yields of poplar and willow on reduced and even non-fertilised stands do not decrease, but instead increase, although the absolute yields grow over time. One of the reasons for this phenomenon seems to be mycorrhica...

The different inputs are connected with upstream processes, i.e., the provision of diesel fuel, pesticides and fertilisers, which can affect overall GHG emissions decisively (the supply of, e.g., nitrogen fertiliser generates large amounts of N20 see Table 7.6). 

The exclusion of Chilean nitrate and all synthetic nitrogenous fertilisers,... 

Eppendorfer, W. H., Bille, S. W. (1996). Free and total amino acid composition of edible parts of beans, kale, spinach, cauliflower and potatoes as influenced by nitrogen fertilisation and phosphorus and potassium deficiency. Journal ofthe Science of Food and Agriculture, 71,449M58. 

More than one-half of all the manufactured nitrogen fertiliser (first produced in 1913) ever used on the planet has been applied since 1985. 

Some of the ammonia produced by the Haber process is used to produce nitric acid. If ammonia is then reacted with the nitric acid, we have the basic reaction for the production of many artificial fertilisers. The use of artificial fertilisers is essential if farmers are to produce sufficient crops to feed the ever-increasing world population. Crops remove nutrients from the soil as they grow these include nitrogen, phosphorus and potassium. Artificial fertilisers are added to the soil to replace these nutrients and others, such as calcium, magnesium, sodium, sulfur, copper and iron. Examples of nitrogenous fertilisers (those which contain nitrogen) are shown in Table 11.7. 

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