Fertilizers are key to rejuvenating the soil by providing nutrients the plants need to grow healthily.
In nature there are 17 critical plant nutrients: The macronutrients nitrogen, phosphorus, potassium, calcium, sulphur, magnesium, oxygen, hydrogen, carbon, and the micronutrients iron, boron, chlorine, manganese, zinc, copper, molybdenum and nickel.
When crops are harvested, the nutrients follow the crop. Important nutrients are therefore removed from the soil. Often the soil is not able to replenish all the nutrients by itself, that is where fertilizers supply the nutrients that are lacking.
To keep up with the world´s rising population, higher crop yields are essential.
In the US alone, the average corn yields have more than doubled since 1968(1), through more effective farming.
Both organic and mineral fertilizers can be used to replenish the soil. The nutritional content of organic fertilizers is low compared to mineral fertilizers, which are concentrated and have a strictly controlled nutrient content.
All the nutrients contained in different fertilizers are found in nature.
The most common sources of nutrients in mineral fertilizers are nitrogen, potassium and phosphate.
Nitrogen originates from the air. The most common process in nitrogen fertilizer manufacturing is to create ammonia from a mixture of nitrogen from the air and hydrogen from natural gas.
Air consists of 78 percent nitrogen, but plants cannot get the nitrogen needed directly from the air – they need to take it up through their roots from the soil.
Potassium is sourced from old sea and lake beds formed millions of years ago.
Potassium fertilizers are based on naturally occurring potassium chloride. This is somewhat similar to table salt – sodium chloride.
The ash from burning wood or straw is high in potassium, this is where the name ‘potash’ originates.
Since potassium sources are often located far below the soil surface (1-2km depth), plant roots are unable to reach them naturally.
The world´s biggest potassium producers are Canada, Russia, Belarus and China.
Phosphate is sourced from insoluble calcium phosphate rocks – often referred to as “rock phosphate”. In this form it is not available to plants. Rock phosphate is made available for the plant usually through a chemical process to create plant friendly fertilizers.
China, Russia and Morocco have some of the world´s largest deposits of phosphate rock.
Nitrogen (N), phosphate (P), and potassium (K) can also be combined to form NPK compound fertilizers, that provides the crop with the 3 major nutrients at the same time.
The alternative to mineral fertilizers is organic fertilizers which are based on materials with a biological origin. These include animal wastes, crop residues, compost, biosolids and more.
Without fertilizers, the soil would be depleted and therefore plants would be particularly difficult to grow. They cannot survive on water alone, and nor can we.
Pesticides are synthetic or natural chemicals used to control pests. Pesticide is a commonly used term for all crop protection chemicals, which also include fungicides that control fungal diseases, herbicides that control weeds.
Fertilizers, on the other hand, supply natural nutrients to make crops grow.
The role of fertilizers is to increase yield and ensure healthy produce by supplying the right balance of nutrients to the soil.
"Without fertilizers, the soil would be depleted and therefore plants would be particularly difficult to grow. They cannot survive on water alone, and nor can we. If we want good nutritious food, plants need nutrition and that makes our food much more enjoyable," says Barry Bull, plant nutrition consultant.
Fertilizers do not alter the DNA of crops. Instead they improve the growth and quality of the crop by adding important nutrients.
The amount of nutrients added is chosen by the farmer after analysing the soil and determining the requirements of individual crops.
Fertilizing in the correct way can have a great impact on crops´ yield, appearance and nutritional value.
Eating crops from a fertilized field, or meat from animals that have grazed on a fertilized pasture, does not pose any health risks for animals or humans.
On the contrary, the nutrients in the fertilizer required for crop growth, are the same nutrients required for human growth and development. It is a fact that approximately half of the world’s population today has food on the table due to fertilizers.
Careful fertilizing is key to increasing crop yields on existing farmland, which in turn helps combat disorders caused by malnutrition.
In countries where specific nutrient deficiencies are a problem, fortifying fertilizers with the relevant micronutrients have also helped better the health of large populations.
Zinc and selenium are two examples of minerals that have been successfully applied to fertilizers to combat deficiencies in large populations.
1 - Historical Corn Grain Yields for the U.S. (Purdue University website/Corny News Network)