Story of Fertilizers
Start of chemical Fertilizers
Through the 1800's, heavily populated countries in Europe such as Germany and Britain used guano from islands off the coast of Peru and salt petre from Chile as a source of natural nitrogen fertilizer. This trade was much like our current oil trade in importance both for food security and politically.
By the end of the 19th century these sources of fixed nitrogen were running out. Scientists were challenged to come up with a process of making fixed nitrogen from the nitrogen in the air.
The winner of the race was Fritz Haber. His tabletop contraption used high pressure, heat and a catalyst to slowly, drop by drop, synthesize a cup of ammonia over the course of two hours.
Importance of Nitrogen
More than 175 years ago, a scientific debate was raging in Europe over the importance of N for the growth of plants. British scientists Bennet Lawes and Joseph Henry Gilbert settled the debate when they published research showing that the addition of N fertilizers increased wheat yields in England. Fifty years later, industrialized nations were challenged with how to feed their growing populations and Great Britain was importing the majority of its wheat. In 1898, William Crooks, president for the British Association for the Advancement of Science, called for chemistry researchers to find solutions to aid in the manufacture of N fertilizers to help solve the coming food crisis.
Haber–Bosch process
The solution soon came from German scientist Fritz Haber, who discovered in 1909 that the chemical reaction of N and hydrogen-produced ammonia—the main component in nitrogen-based fertilizers. In July of that same year, Germany’s largest chemical company, BASF, funded German chemist and engineer, Carl Bosch, to develop commercial scale production of ammonia. The process wasn’t easy, however. Ammonia production depended on high temperatures and pressures, as discovered by Haber. Much of the necessary machinery had to be invented to handle the extreme production conditions. Bosch’s machine, unveiled in 1914, stood 26 feet tall and could produce 198 pounds of ammonia per hour. Soon after the plant was built, World War I began, and the new plant was used to manufacture material for explosives. Following the war’s end, Germany attempted to keep the Haber-Bosch process a secret. During negotiations at Versailles, however, Bosch, who was a member of the German negotiating team, offered the French government the technical details they would need to build their own Haber-Bosch plant. The French began producing ammonia in the early 1920s, followed soon by the British and Americans. Haber’s and Bosch’s contributions to ammonia production were honored with two Nobel Prizes. Haber was presented with the Nobel Prize in 1920 for his research that unlocked the ammonia production process. In 1932, Bosch and Frederick Bergius received the Nobel Prize for their contributions to the invention and development of chemical high pressure methods. Today, a modern ammonia production facility produces approximately 1,000 tons of ammonia per day. These advances in ammonia production have significantly increased yields of food and feed grain crops. In just 70 years, there’s been a six-fold increase in U.S. corn yields, thanks to the abundance of available nitrogen. The world simply cannot do without N fertilizer, and the contributions made by Fritz Haber and Carl Bosch. Through fertilizer, we have the means to ensure that each growing season’s crops have the nutrients necessary to yield nutritious, bountiful foods for an increasing global population.
Liebig's Law of the Minimum
In the mid-1800s, German chemist Justus von Liebig formulated the "Law of the Minimum," which highlighted the idea that plant growth is limited by the availability of the scarcest essential nutrient. Liebig's work laid the foundation for the scientific study of plant nutrition and the development of synthetic fertilizers. Liebig's Law of the Minimum states that the local yield of terrestrial plants should be limited by the nutrient that is present in the environment in the least quantity relative to its demands for plant growth, and this statement has been confirmed worldwide. This Law also provides a conceptual foundation for the response of aquatic ecosystems to nutrient enrichment: surface waters receiving low inputs of nitrogen and phosphorus are typically very unproductive, whereas highly nutrient-enriched waters typically exhibit abundant growth of aquatic plants.
Importance of Phosphorus
Samuel W. Johnson (1830–1909) was an American chemist who contributed to the understanding of phosphorus as an essential nutrient for plant growth. His research highlighted the importance of phosphorus in root development and overall plant health. Johnson's research aimed to quantify the specific nutrient requirements of plants, particularly focusing on phosphorus. He recognized that phosphorus was a vital nutrient for plant health and played a critical role in root development, energy transfer, and overall plant metabolism. Johnson was one of the pioneers in utilizing plant analysis techniques to determine nutrient deficiencies. He conducted extensive experiments in greenhouses and fields, meticulously studying the effects of different nutrient applications on plant growth. His observations led him to conclude that phosphorus deficiency was a common limitation in crop production. Based on his research findings, Johnson advocated for the application of phosphorus-containing fertilizers to enhance crop yields. He believed that by addressing phosphorus deficiencies in soils, farmers could significantly improve plant growth, root development, and ultimately, agricultural productivity. Samuel W. Johnson's work laid the groundwork for the integration of phosphorus fertilizers into mainstream agricultural practices. His research provided evidence for the critical role of phosphorus in promoting root growth, flowering, and fruit production. Today, phosphorus remains one of the essential nutrients in fertilizers, and his contributions continue to influence nutrient management strategies.
Evolve of Potash as a fertilizer
The understanding of potassium's importance as a fertilizer evolved over time through the contributions of multiple researchers and scientists. Unlike some other elements like nitrogen and phosphorus, there isn't a single individual or a specific moment of discovery attributed to the recognition of potassium's significance as a fertilizer. Instead, it emerged gradually as part of the broader understanding of plant nutrition and agricultural practices. The term "potash" originally referred to the practice of extracting potassium-rich salts from wood ashes. In regions where wood was burned for fuel, the ashes were collected and leached to obtain soluble salts containing potassium. These salts, known as potash, were used as a source of potassium for agricultural purposes. As agricultural demand grew, the potash industry expanded. In the 18th and 19th centuries, countries with access to potash-rich deposits, such as Germany and North America, became major producers of potash fertilizers. The term "potash" eventually extended to include various potassium-containing compounds, not just those derived from wood ashes. Advances in mining techniques allowed for the extraction of potassium-rich minerals from underground deposits. Sylvite (potassium chloride), for example, became a major source of potassium for fertilizers. Mining practices evolved to efficiently extract and process these minerals for agricultural use.
NPK Fertilizers Formulation
As scientists understood the importance of these three nutrients, they began to explore the optimal ratios in which they should be applied to crops. Different crops and soil types require varying ratios of NPK to achieve the best growth and yield outcomes. The concept of "balanced fertilization" emerged, where the application of NPK in appropriate proportions led to improved agricultural productivity. The formulation of NPK fertilizers involves determining the appropriate ratios of these nutrients based on the specific needs of different crops, soil types, and growth stages Different crops have varying nutrient requirements at different stages of their growth cycle. Research and agronomic knowledge help determine the optimal nutrient ratios for each crop. For example, leafy vegetables may require higher nitrogen levels, while fruit-bearing crops benefit from more phosphorus and potassium. Based on the specific needs of a particular crop, scientists and agronomists create custom NPK formulations. These formulations consider factors like the crop's growth stage, soil characteristics, expected yield, and environmental conditions.