What is fertilizer?
The widespread use of commercial mineral fertilizers is one of the major factors in ensuring global food security in recent times. Over 48% of the more than 7 billion people alive today are living because of increased crop production made possible by applying nitrogen (N) fertilizers. The extent to which world food production depends on fertilizer use will inevitably increase in the future.
Without fertilizers, the world would produce only about half as much staple food, and more forested lands would have to be put into production. The potential impact of fertilizers in meeting global crop production needs was illustrated by the ears of corn displayed by a farmer from Nigeria at the Millennium Summit in 2000 at the United Nations in New York City. He had been growing maize without fertilizer and was unable to meet his family’s food needs.
When he started using fertilizer, the yields greatly increased and he was able to feed his family and had enough maize to sell to others. Globally, 180.6 Mt of nutrients were used for crop production in 2013; 70.2 % and 29.8 % were used in developing and developed countries. China and India, the two most populous countries in the world, consumed 42.8 % of the total amount of nutrients applied through fertilizers in the world.
Why use fertilizers?
The goal of nutrient management is to provide an adequate supply of all essential nutrients for a crop throughout the growing season. If the amount of any nutrient is limiting at any time, there is a potential for loss in production. As crop yields increase and as increasing amounts of nutrients are exported from the fields where crops are grown, the nutrient supply in the soil can become depleted unless it is supplemented through the application of fertilizers.
Fertilizers need to be applied to all types of crop production systems in order to achieve yield levels which make the effort of cropping worthwhile. Modern fertilization practices, first introduced in the last half of the 1800s and based on the chemical concept of plant nutrition, have contributed very widely to the immense increase in agricultural production and have resulted in better quality food and fodder.
Furthermore, the farmer’s economic returns have increased substantially due to fertilizer use in crop production. German agronomist, Carl Sprengel (1787–1859) was the first to publish on the Law of the Minimum around 1837 which states that plant yield is proportional to the amount available of the most limiting nutrient, and if that nutrient deficiency is corrected, yield will improve to the point of the next most limiting nutrient in the soil.
German chemist, Justus von Liebig (1803–1873) is generally credited for promoting this concept, and for developing the first mineral fertilizer to be used as a part of sustainable agriculture production systems. The Law of the Minimum is commonly illustrated by the staves in a broken barrel, with each stave representing essential inputs for crop growth.
Soil fertility and its improvement
Fertile and productive soils are vital components of stable societies because they ensure the growth of plants needed for food, fiber, animal feed and forage, industrial products, energy and for an aesthetically pleasing environment. Soil fertility integrates the basic principles of soil biology, soil chemistry, and soil physics to develop the practices needed to manage nutrients in a profitable and environmentally sound manner. Soils differ widely in their ability to meet the nutrient requirements of plants; most have only moderate natural soil fertility.
