FAQ

What is fertilizer?

Fertilizers are nutrients for plants, regardless of source.

Besides sunlight, carbon dioxide, oxygen and water, thirteen elements are considered
essential for plant growth.
 These are divided into:
Major nutrients - N, P, K (nitrogen, phosphorus, potassium).
Secondary nutrients - Ca, Mg, S (calcium, magnesium, sulphur).
Micro nutrients - Fe, Mn, B, Zn, Cu, Mo, Cl (iron, manganese, boron, zinc, copper, molybdenum, chlorine).
Some crops may benefit from other elements, e.g. Na (sodium) for sugar beet and some tropical crops, and Si (silicon) for maize, grasses and particularly rice.The primary and secondary nutrients are required in the largest amounts, although there are large variations of requirement between crops. They are the constituents of many plant components including proteins, nucleic acids and chlorophyll, and are essential for processes such as energy transfer, maintenance of internal pressure and enzyme function. Micronutrients are the ‘vitamins’ of plants. They are not needed in large quantities but are necessary for plant health.
The components of mineral fertilizers are normal constituents of the soil in the inorganic form and are environmentally benign. In organic fertilizers the nutrients are partly tied up in organic compounds that have to be mineralized to be available to plants.

Mineral fertilizers can supply the balance between the amount of nutrients available from other sources like the soil, air or organic manures, and a crops nutrition requirement.


 

Why are mineral fertilizers necessary?

Fertilizers maintain soil fertility/productivity through supplying/replacing essentialplant nutrients and therefore make a vital contribution to economic crop production. Cultivated soils do not usually contain sufficient amounts of plant nutrients for high and sustained crop yields. Harvesting crops removes nutrients and if they are not replaced (through use of fertilizers) soil mining results, yields will diminish, crops will develop deficiency symptoms and in extreme cases, fail altogether.

The world's human population is increasing, demanding increased food production from agricultural land, at affordable prices. Fertilizer use on an expanding scale is required for enhanced and economic agricultural productivity. Fertilizers are necessary to support an affordable and sustainable agriculture.Yara has a balanced nutrient range of fertilizer products to provide those nutrients in short supply. Optimal fertilizer application, with the correct balance of nutrients is required to ensure the economic production of both high yielding and high quality crops.
 

How are fertilizers produced?

The production processes vary in accordance with the nutrients needed to be
included in the fertilizer.
The components of finished fertilizer products are relatively simple chemicals, but
highly developed manufacturing technologies are employed in the production of high
quality mineral fertilizers. There are various steps involved in their manufacture, from
the raw materials, through intermediates, to the finished products.Nitrogen (N) Fertilizers:
The supply of nitrogen, determines a plant’s growth, vigour, colour and yield. Increasing
the nitrogen supply to a crop tends to increase the crop’s content of substances that
contain nitrogen such as proteins and vitamin B1.
The intermediate product in the case of nitrogen fertilizers is ammonia (NH3), which is produced by combining nitrogen extracted from the air with hydrogen which is obtained from natural gas, or through the hydrocarbon steam reforming process.Approximately 85% of the ammonia plants in the EU use natural gas. Measures to improve production processes have focused on reducing the amount of hydrocarbon
feedstock required to produce a tonne of ammonia.
The further processing of ammonia produces straight N fertilizers such as urea, ammonium nitrate and calcium ammonium nitrate, as well as solutions of the above fertilizers and ammonium sulphate. Ammonia is also the main intermediate for many multi-nutrient fertilizers.

Phosphate (P) Fertilizers:
Phosphorus is required for good rooting and resistance to drought, for plant growth and development, for the ripening of seed and fruit and in the manufacture and use of sugars and complex carbohydrates. A good supply of phosphorus is essential in the first stages of a plant’s life and for early maturity.
This nutrient is often described or declared as phosphate (P2O5) rather than phosphorus (P). This is just a convention and the terms can be used interchangeably but care needs to be taken with fertilizer recommendations, as 1 kg P is equivalent to 2.291 kg P2O5. Rock phosphate (27 - 38% P2O5) is the raw material source from which most types of phosphate fertilizers are produced, with minor exceptions such as basic slag (12 - 18% P2O5), which is a by-product of steel production In its unprocessed state, rock phosphate is not suitable for direct application, as the phosphorus it contains is insoluble at soil pH above 6.5. To transform the phosphorus into a plant-  available form and to obtain  a more concentrated product, phosphate rock is processed using
sulphuric acid, phosphoric acid and/or
nitric acid.
 Acidulation by means of sulphuric acid produces either phosphoric acid, an intermediate product in the
production of triple superphosphate (TSP), monoammonium phosphate (MAP), diammonium phosphate (DAP) and complex fertilizers, or single superphosphate (SSP). Acidulation using phosphoric acid produces TSP, and acidulation using nitric acid produces NP slurries for use in the manufacture of complex fertilizers.

Potash (K) Fertilizers:
Potassium controls water relations in plants and helps give plant cells their turgor or stiffness. This is important for crop quality and resistance to disease. Sufficient potassium is also critical for vitamin and mineral content, for texture, firmness and resistance to drought. It is particularly significant in plants that store large amounts
of sugar and starch, like potatoes. It is also vital for the root nodule bacteria on legumes which fix nitrogen from the air.
This nutrient is often described or declared as potash (K2O) rather than potassium (K).Whilst just a convention, the terms can be used interchangeably but care needs to be taken with fertilizer recommendations, as 1 kg K is equivalent to 1.205 kg K2O. Most potassium used in fertilizer production is taken from natural deposits of potassium chloride. The mined material is crushed and purified by the removal of rock particles and salt and then applied direct, or more usually incorporated in NPK fertilizers.
Relatively small amounts of potassium sulphate also are used in fertilizers.

Multi-nutrient Fertilizers:
Multi-nutrient fertilizers produced in the EU are either complex fertilizers (every particle contains the same ratio of nutrients), or blends (made by mixing particles of different materials). Typically, complex NPK fertilizers are manufactured by producing slurries of ammonium phosphates, to which potassium salts are added prior to granulation or prilling. PK fertilizers, on the other hand, are generally produced as compounds by the steam granulation of super phosphates (SSP or TSP) with potassium salts.Yara has a balanced nutrient range of fertilizer products, which has been specially developed for the world’s major crops. The Company produces and markets complex NPK’s, Nitrates (ammonium nitrate, calcium ammonium nitrate and
calcium nitrate), UAN, Urea, Ammonia and other differentiated and value added speciality fertilizers containing one or more micronutrients.








 

 

Why is adding sulphur to fertilizers more necessary now than previously?

Fertilizers maintain soil fertility/productivity through supplying/replacing essential plant nutrients and therefore make a vital contribution to economic crop production.Cultivated soils do not usually contain sufficient amounts of plant nutrients for high and sustained crop yields. Harvesting crops removes nutrients and if they are not replaced (through use of fertilizers) soil mining results, yields will diminish, crops will
develop deficiency symptoms and in extreme cases, fail altogether.The world's human population is increasing, demanding increased food production from agricultural land, at affordable prices. Fertilizer use on an expanding scale is required for enhanced and economic agricultural productivity.

Fertilizers are necessary to support an affordable and sustainable agriculture. Yara has a balanced nutrient range of fertilizer products to provide those nutrients in short supply. Optimal fertilizer application, with the correct balance of nutrients is required to ensure the economic production of both high yielding and high
quality crops.



 
 

Organic fertilizers:Are they environmentally better or worse than mineral fertilizers?

Both organic and mineral fertilizers have their place in sustainable agriculture.
Manures and crop residues are by-products in agriculture that contain valuable crop
nutrients and should be used wherever available and taken into account when making
fertilizer recommendations.
There are not enough nutrients in organic wastes to compensate for those removed
by high yielding crops and for unavoidable losses, the balance must be made up from
mineral fertilizers.
There are considerable environmental problems with the use of manures. Techniques
for improved handling and soil application are being developed.
Part of the nitrogen in manures is not available to the crop during the growing season,
with some mineralized later during non-vegetative periods, then lost through leaching.
Ammonia loss during open storage or after surface spreading of manures can be
substantial.
The separation of livestock and arable farming, with the concentration of animals in
some regions and arable crops in others, has lead to nutrient distribution inefficiency,
with a surplus in the animal farming regions. The low nutrient content and bulky nature
of manures makes transportation inconvenient and costly.

What happens to nitrogen fertilizer?

So long as it is applied to meet crop requirement and in accordance with good
farming practice, with locally derived rates and timing, it will be largely taken
up by the plant. It is then present in agricultural outputs, grains, fruit, vegetables,
milk, meat, and eggs.
The soil nitrogen cycle explains the nitrogen pathways.
Nitrogen fertilizers dissolve in soil water and release ammonium-N and nitrate –N,
both of which are taken up by crops.
Of the fertilizer nitrogen applied:
Much is taken up by the plant.
Some is used by soil microbes and incorporated in the soil’s pool of organic matter
(called microbial nitrogen immobilization).
The remainder is at risk of loss through leaching and gaseous products (ammonia,
nitrogen oxides and di-nitrogen) The amounts are variable depending on the quantity,
time and type of nitrogen fertilizer applied, as well as the environmental conditions
of soil and climate.
Yara has an extensive R & D programme to improve fertilizer N use and to
minimise risks of nutrient loss from the soil.