Fertilizers feed the world
The use of fertilizers by man to improve soil quality is as old as the practice of agriculture, dating back to the Neolithic Age, more than twelve thousand years ago. But it was at the turn of the 19th and 20th centuries that modern agriculture gained dimension, benefiting from scientific advances in chemistry.
A global need
The demographic explosion that followed World War II brought yet another great battle to the 20th century: that of feeding humanity. The exponential increase in agricultural production guaranteed that the world had access to food, but this was only possible because chemical fertilizers played a fundamental role in this process.
Fertilizer is the food that plants need to grow and develop. Plants need light, carbon dioxide, water, and nutrients such as nitrogen, phosphorus, and potassium. But it is difficult for soil to provide all of these elements in ideal quantities. And it is to fill this deficit that fertilizers gain strength, providing plants with a better use of their resources.
The first true contact of man with fertilizers dates back to the Neolithic period, twelve thousand years ago, when agriculture and livestock allowed prehistoric man to become sedentarized.
Animal waste, plant debris, ashes, and clays were the first natural fertilizers used by man to fertilize the earth, during the Neolithic Revolution or “Agricultural Revolution”, which took place in different places, such as the Middle East, Asia and Latin America, expanding around the world.
Throughout this period, prehistoric man became sedentarized. He developed agriculture, domesticated animals and plants, invented advanced metal utensils, and established cultural and commercial exchange relations with other groups. Thanks to sedentary lifestyle, the population increased and the first cities or settlements appeared.
Farmers were dedicated to tilling and fertilization techniques with ash and animal manure continued to flourish, becoming a kind of business in the region that comprised France, Belgium and Flanders, already during the Middle Ages. To compensate for the loss of nutrients in the soil, farmers also introduced fallow and crop rotation.
But the development of cities, with their enormous food supply needs and the emergence of industry, exponentially accelerated the consumption and dispersion of these nutrients from the soil, far beyond their capacity for regeneration.
The Alchemists
Large-scale agricultural production and the abundance of current food is only possible because a group of notable people from the 19th century - in the demand of the Industrial Revolution and the consequent increase in the world population - made use of chemical experiments to discover what affected the growth of vegetables.
Contrary to the theories of the time, that plants absorbed the organic substances resulting from the decomposition of animal bodies in the soil, the German chemist Justus Von Liebig (1803-1873) proved that plants need certain mineral elements to improve their growth.
In 1840, Liebig shook the foundations of the agricultural science of those times by defining the basic constitution of modern chemical fertilizers: nitrogen, phosphorus, and potassium. The young alchemist, who spent most of his life inside a chemistry laboratory, took about half a century to complete and present his work. He promoted heated debates about how to avoid hunger and provide nutritional well-being for populations and is now known as the “Father of the Fertilizer Industry”.
Although the first fertilizer plant in the world appeared in 1843 in England, the great step in this area was taken once again by Germany with several discoveries, such as those of the physicist-chemist Friedrich Ostwald (1853-1932). In his work, he discovered the process of preparing nitric acid from the oxidation of ammonia, facilitating the mass production of fertilizers and explosives.
Nitric acid
Nitric acid is a chemical compound represented by the HNO3 formula used in the manufacture of fertilizers for agriculture. It is the second most manufactured and most consumed acid in the industry, second only to sulfuric acid. In Portugal, nitric acid is produced exclusively by Bondalti, obtained from the catalytic oxidation of ammonia, according to the Ostwald Process.
As early as the 20th century, German chemist Fritz Haber discovered how to extract nitrogen from air by synthesizing ammonia, and Karl Bosch perfected Haber's method for obtaining synthetic ammonia. The process of obtaining it by this method made it possible to synthesize almost all of the ammonia necessary for the production of fertilizers. In addition, the fact that ammonia can be converted into compounds useful in the synthesis of explosives made its exploration even more successful during the First World War.
The universalization of the use of chemical fertilizers has considerably increased food production around the world. Today, it is unquestionable that fertilizers are essential for the survival of plants, animals, and human beings, providing food to a global population that is expected to reach nine billion before 2050.
The great challenge of the 21st century will be to continue to improve the yield of agricultural land and to reduce, at the same time, the environmental impact of agriculture.
