More than 3.54 billion people worldwide today eat thanks to nitrogen fertilizers. Yet, it is something we take for granted. From manure to nutrient specific optimized applications, fertilization has come a long way.
The History of Fertilization
Around 4,400 to 7,900 years ago farmers began to notice significant differences between the yield of their small fields. Crops grew much better in areas where now domesticated animals gathered. Soon the farmers understood that the animal’s dung was the determining factor behind larger yields and increased crop growth. They began to manually make use of the manure and spread it across their fields to receive better harvest results – and better results they received. Making use of animal dung became the new and a more reliable way for farmers across the globe to fertilize their plants. However, as we learned in the previous chapter, farmers are innovators.
We fast forward to 18th century England where another source for fertilization was found. Mixing ground up animal bones into the soil was shown to improve yields. By 1815, the demand of animal bones as fertilizers became so big that England started to import bones from across Europe to meet their demands. Similarly in the United States, ground bison bones were a huge source for fertilizer.
Yet, even though the advantages of fertilizers were clear to each farmer at the time, the exact reason for their success were generally unknown. The plants’ need for nutrition, the key compounds that lie behind their growth, were not well understood. By the 19th century, great progress was made and the needs of plants much better understood. Nitrogen (N), phosphorus (P), and potassium (K) were identified to be key elements in the growth and development of plants. Still today, nitrogen fertilizers are the most commonly used and allow us to sustain over 48% of the world’s population.
From Air to Fertilizer
The arguably most important development within fertilization took place between 1909 and 1914. Chemist Fritz Haber invented a process by which ammonia is directly synthesised from nitrogen and hydrogen from the air. Continuing on his work Carl Bosh invented the required machinery to mass scale the process discovered by Harber. Together they enabled the most economical production of ammonia. This process also known as the Haber-Bosch process is still the main way in which we produce nitrogen fertilizer today and is directly responsible for sustaining 3.54 billion people today. For their immensely impactful work both Haber and Bosch received the Nobel prize in chemistry.
Too Much of Something Good
The impact of nitrogen fertilizer on the human population is evident, yet its impact on our environment cannot go unnoticed. As agronomists and farmers noticed hundreds of years ago, knowing what you plants need has a direct impact on their wellbeing and yield. It is not enough to know what compounds they need, how much they need is equally important. More nitrogen fertilizer does not mean more growth. Too much becomes harmful for the crop. In cereal crops too much nitrogen can manifest itself as so-called lodging. Lodging causes the crops to lie down, which increases their moisture leading to their rotting. Lodging also makes it challenging for the harvester to reach the plant. The excess nitrogen that the crops are unable to take up leakes into the groundwater which becomes polluted and a harm to surrounding lakes ecosystems. Thanks to modern technological development, we can determine the exact amount of nitrogen each crop type and area of the field requires for optimal growth and yield.
The earliest archaeological discoveries around the cultivation of rice date back to 7000–5000 BCE in China…
Wheat is a rather picky crop, demanding specific conditions in order to grow and prosper. Even though wheat came about…