Fertiliser straight fertilisers

It is also possible to compare the values of straight fertilisers of different composition on the basis of cost per kilogram of plant food, e.g. the cost of a kilogram of nitrogen in ammoiuum nitrate (34.5% N) is 87 pence from the calculation above. This compares with the cost of a kilogram of nitrogen in urea (46% N) which is ... 

Straight fertilisers supply only one of the major plant foods. 

Muriate of potash (potassium chloride). As now sold, it usually contains 60% K O. It is the most common source of potash for farm use and is also the main potash ingredient for compound fertilisers containing potassium. As a straight fertiliser it is normally granulated, but some is marketed in a powdered form. KCl is found in vast quantities all over the world and is mined from rock deposits left by dried-up oceans. It is nearly always found in conjunction with NaCl and the two are separated by a flotation process. 

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. 

Abstract This chapter explains the importance of feeding crops and ensuring that soil fertility is maintained. It discusses the main elements required by crops, both major and trace. It explains why liming is so important for crop nutrition. It deals with the calculations and sources of information needed to accurately decide on fertiliser application rates, and cost them. It describes the materials used on-farm as fertilisers and explains the differences between straights, compounds and blends, as well as dealing with liquids and solid fertilisers. There is a section on the use of oiganic manures and slurries and how to make best use of them. Finally, the chapter deals with the effect of fertilisers on the environment, during both their manufacture and application. 

Normally, the well-mixed granulated compounds cost more than the equivalent in straights . Bulk blends of straights are usually cheaper. Fertiliser priees have varied considerably in recent years actual costs at ai r time should be substituted in the calculations shown. 

The nitrogen in many straight and compound fertilisers is in the ammonium (NH cation) form but, depending on the soil temperature, it is quickly changed by bacteria in the soil to the nitrate (NOj anion) form. Many crop plants, e.g. cereals, take up and respond to the NO3 anions quicker than the NH cations, but other crops, e.g. grass and potatoes, are equally responsive to NH and NO ions. 

This diagram shows the raw materials the factory needs to make 1000 tonnes of straight and 1000 tonnes of compound fertiliser a day, and the steps in the production process t/day stands for tonnes per day. 

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