Fertilizers are currently responsible for between 40 and 60 percent of the world’s food supply (Source: The Fertilizer Institute).

Fertilizers are any solid, liquid or gaseous substances containing one or more plant nutrients that are either applied to the soil, directly on the plant (foliage), or added to aqueous solutions, in order to maintain soil fertility, improve crop development, yield and/or crop quality. The purpose of fertilizers is to supplement the natural supply of soil nutrient, build up soil fertility in order to satisfy the demand of crops with a high yield potential and to compensate for the nutrients taken by harvested products or lost by unavoidable leakages to the environment, in order to maintain good soil conditions for cropping. (Source: The International Fertilizer Industry Association, IFA).

Historical Background

Fertilizer application prior to the 19th century was generally limited to the application of animal and plant waste materials sourced local to farms. A first boom in industrial scale fertilizer production for global consumption began with the large-scale mining of guano (sea bird excrement), largely from islands off Peru. Potassium mining in Germany began in the 1860s, and manufacturing of the first phosphate fertilizers from phosphate ores began around the same time, as did the mining of Chilean Nitrates. Industrial fertilizer production really took off in the early parts of 20th century with the discovery of the Haber-Bosch process for fixing Nitrogen from the atmosphere, which significantly increased the availability of Nitrogen fertilizers, in turn increasing demand for complementary fertilizers with other nutrients.   

Figure 1 - Global Fertilizer Consumption by Major Nutrients


Source: FAO (Food and Agriculture Organization of the United Nations)

Nitrogen is likely to remain the most important fertilizer nutrient globally, but Potassium and Phosphate have been increasing their market share slightly over the last 12 years. The main drivers of demand growth over recent years and decades are thought to be a combination of population growth, changing diets, and changing agricultural practices that are demanding higher agricultural yields per hectare of arable land. 

Figure 2 - Global Fertilizer Consumption Compound Annual Growth Rate by Nutrient Content, 2002-2014)

Fertilizer Consumption Annual Growth Rate
N2.3%
P2O52.5%
K2O2.9%
Source: FAO

Consumption of the three main nutrients varies significantly by crop type and region, with fertilizer consumption growing faster in South America than in other regions in recent years. In South America, Phosphorus and Potassium account for a significantly higher percentage of fertilizer consumption than is the case globally.

Figure 3 - Fertilizer Consumption by Major Nutrient, 2014

FertilizerWorldSouth America
N56%34%
P2O524%33%
K2O19%33%
Source: FAO

Figure 4 - Global Fertilizer Consumption Compound Annual Growth Rate by Region, 2002-2014

Source: FAO

Commercial Fertilizers

The nutrients required for healthy plant life are classified according to the elements, but compounds containing these elements are the basis of fertilizers that are available in a wide range of formulations and specifications.

Nitrogen Fertilizers: The largest production of fertilizer is attributable to nitrogen fertilizers, production of which is largely attributable to the Haber-Bosch process developed in the early 1900s for fixing Nitrogen in the atmosphere by converting it to Ammonia, which can be used directly as a fertilizer or converted into other fertilizer products. The Haber-Bosch process typically also requires significant quantities of natural gas. The commonest nitrogen fertilizer in use globally today is Urea.

Phosphate Fertilizers: Phosphate is typically extracted from naturally occurring mineral deposits as phosphate ore, which can be used as Direct Application Phosphate Rock (“DAPR”), depending on the reactivity of the rock and the nature of the soil and crops to be fertilized. As is more often the case globally today, the phosphate rock is chemically processed to produce “chemical” phosphate fertilizers, of which diammonium phosphate is currently the most widely used globally.

Potassium Fertilizers: The majority of potassium fertilizer production globally currently is sourced from mines that extract potassium salts from solid rock evaporite deposits in the form of Potassium Chloride (Muriate of Potash or “MOP”). However, significant production is also sourced from lake brines, including the Dead Sea and Great Salt Lake. SOP, which has the benefits of adding sulfur as an additional nutrient and having no chloride, is not produced from mines, but can be produced from MOP through energy intensive processing, or directly from lake brines.  

Complex and Speciality Fertilizers: Not shown in the table of common fertilizers shown below are complex fertilizers (developed to provide a balanced nutritional supply of multiple nutrients) or specialty fertilizers designed primarily to provide secondary nutrients including Sulfur and Magnesium. 

Figure 5 – Main Nutrients as % of product in common fertilizers

Nitrogen Fertilizers
Common NameNP2O5K2O
Ammonia8200
Ammonium sulphate2100
Ammonium nitrate33-34.500
Calcium ammonium nitrate20.4-2700
Urea45-4600
Phosphate Fertilizers
Common NameNP2O5K2O
Single superphosphate (“SSP”)016-200
Triple superphosphate (“TSP”)0460
Diammonium phosphate (“DAP”)18460
Monoammonium phosphate (“MAP”)11520
Direct Application Phosphate Rock (“DAPR”)02-400
Potash Fertilizers
Common NameNP2O5K2O
Muriate of potash (“MOP”) (potassium chloride)0060
Sulphate of potash (“SOP”)(potassium sulphate)0050
Sulphate of potash magnesia0022-30
Source: IFA

Most fertilizer specifications state the concentration of nutrient elements in their elemental form, but a common exception is for potassium and phosphorus, for which the most common convention is to represent potassium (K) as dipotassium oxide (K2O) and phosphorus (P) as phosphorus pentoxide (P2O5) To convert K2O to K, multiply the K2O figure by 0.83. To convert P2O5 to P, multiply the P2O5 figure by 0.44.

Theoretical Science and the Practice of Agriculture

In general, the aim of agricultural crop nutrition science is to help farmers maximize yields while minimizing costs. The modern agricultural approach to understanding how best to achieve this goal when growing crops is to use soil analysis and fertilizer application to ensure a balanced supply of nutrients, since an overabundance of one particular nutrient has no benefits (or a negative impact) without sufficient supply of other nutrients.  In practice, farmers and the fertilizer industry are constantly adapting to changes in weather, environment, and markets for agricultural products and fertilizers, as understanding of optimal business solutions continues to evolve and adapt to changing circumstances. 

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