Fertilizer

• 1. From Manure To Ammonia

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  A farmer spreads manure to improve soil fertility. This practice dates back thousands of years. Middle Eastern, Chinese, and Mesoamerican cultures all adopted early agricultural methods that relied on natural materials. Egyptians, Romans, Babylonians, and early Germans used minerals or animal waste to boost farm productivity. The scientific research of plant nutrition began before the work of German chemist Justus von Liebig. His name remains most mentioned as the father of the fertilizer industry. Nicolas Théodore de Saussure and colleagues quickly disproved some simplifications made by von Liebig. John Bennet Lawes, an English entrepreneur, started experimenting with various manures on plants in pots during 1837. He extended these experiments to field crops a year or two later. In 1842 he patented a manure formed by treating phosphates with sulfuric acid. This marked the first creation of the artificial manure industry. He enlisted Joseph Henry Gilbert to perform crop experiments at the Institute of Arable Crops Research.

  The Birkeland, Eyde process served as one competing industrial method for nitrogen-based fertilizer production. A factory based on this process was built in Rjukan and Notodden in Norway. Large hydroelectric power facilities were constructed there to support operations. The 1910s and 1920s witnessed the rise of the Haber process and the Ostwald process. The Haber process produces ammonia from methane and molecular nitrogen taken from air. Ammonia from the Haber process is then partially converted into nitric acid via the Ostwald process. After World War II, nitrogen production plants pivoted towards agricultural uses. These plants had ramped up for wartime bomb manufacturing before the shift. Use of synthetic nitrogen fertilizers increased steadily over the last 50 years of the 20th century. Production rose almost 20-fold to reach 100 million tonnes of nitrogen per year in 2003.

• 2. Nitrogen Fixation And Soil Chemistry

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  Fertilizers enhance plant growth through two primary mechanisms. Additives provide nutrients directly to crops. Other methods modify soil water-holding capacity and aeration to improve effectiveness. Three main macronutrients dominate most formulations: nitrogen, phosphorus, and potassium. Nitrogen drives leaf growth and stem development. Phosphorus supports root formation, flowers, seeds, and fruit. Potassium promotes strong stems and movement of water within plants. Secondary macronutrients include calcium, magnesium, and sulfur. Micronutrients like copper, iron, manganese, molybdenum, zinc, and boron appear in smaller quantities but remain essential. Plants contain four main elements: hydrogen, oxygen, carbon, and nitrogen. Carbon, hydrogen, and oxygen exist widely as carbon dioxide and water. Nitrogen makes up most of the atmosphere yet remains unavailable to plants in its natural form.

  Only free-living bacteria such as Clostridium or symbiotic bacteria living in legume roots can fix atmospheric nitrogen by converting it to ammonia. Two enzymatic reactions determine efficiency for nitrogen-based fertilizers. The first involves hydrolysis of urea into ammonium ion and bicarbonate ion. Many soil bacteria possess the enzyme urease which catalyzes this conversion. Ammonia-oxidizing bacteria like species of Nitrosomonas oxidize ammonia to nitrite. This process is termed nitrification. Nitrite-oxidizing bacteria especially Nitrobacter then oxidize nitrite to nitrate. Nitrate is extremely soluble and mobile. It leaches easily to groundwater then flows into rivers and eventually reaches the sea. This mobility causes eutrophication and algal blooms in freshwater bodies and coastal zones.

• 3. China Leads Global Consumption

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  Agricultural use of inorganic fertilizers reached 195 million tonnes of nutrients in 2021. Fifty-six percent of that total was nitrogen. Asia represented 53% of world agricultural use of inorganic fertilizers that year. The Americas followed with 29%, Europe held 12%, Africa accounted for 4%, and Oceania made up just 2%. China stands as the largest user of each nutrient type globally. India, Brazil, and the United States follow behind China in usage rankings. Yara International operates as the world's largest producer of nitrogen-based fertilizers. A maize crop yielding six to nine tonnes of grain per hectare requires specific amounts of phosphate fertilizer applied during growth cycles. Soybean crops need about half that amount, roughly twenty to twenty-five kilograms per hectare.

  The global mineral market for fertilizers values approximately two hundred billion dollars annually. Potash production occurs primarily in Canada, Russia, and Belarus together making over half of world output. Potash production in Canada rose by eighteen point six percent in both 2017 and 2018. Conservative estimates report thirty to fifty percent of crop yields attributed to natural or synthetic commercial fertilizers. Fertilizer consumption has surpassed the amount of farmland in the United States. Data published by The World Bank shows European Union countries consumed an average of seventy kilograms of fertilizers per hectare arable land in 2020. Total EU consumption peaked at eleven point six million tons in 2017 before declining steadily to nine point three million tons in 2023.

• 4. Dead Zones And Toxic Runoff

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  Synthetic fertilizers used in agriculture create wide-reaching environmental consequences. Agricultural runoff leads to downstream effects like ocean dead zones and waterway contamination. Soil microbiome degradation occurs alongside accumulation of toxic compounds in ecosystems. Nitrogen-rich compounds found in fertilizer runoff cause serious oxygen depletion in many parts of oceans. Coastal zones, lakes, and rivers suffer greatly from this lack of dissolved oxygen. The number of oceanic dead zones near inhabited coastlines continues increasing each year. Cyanobacteria blooms produce harmful toxins that accumulate in food chains and harm human health.

  Phosphorus and nitrogen fertilizers affect soil surface water and groundwater due to mineral dispersion under high rainfall or snowmelt conditions. About half of all lakes surveyed by the United States Environmental Protection Agency were eutrophic in 2007. That figure rose alarmingly to eighty percent in 2012. High phosphorus concentrations promote growth of cyanobacteria and algae whose demise consumes available oxygen. Only a fraction of nitrogen-based fertilizers converts to plant matter. The remainder accumulates in soil or is lost as run-off into surface waters. Nitrate levels above ten milligrams per liter in groundwater can cause blue baby syndrome acquired methemoglobinemia. For each ton of phosphoric acid produced five tons of waste called phosphogypsum are generated annually worldwide. Estimates range between one hundred million and two hundred eighty million tons of this radioactive solid waste created every year.

• 5. Precision Timing And Application Methods

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  Fertilizer application rates depend on soil fertility measured through soil tests and specific crop requirements. Legumes fix nitrogen from atmosphere generally do not require additional nitrogen fertilizer. Timing fertilization with peak nutrient uptake demand optimizes both yield and quality for farmers. Nutrient uptake rates remain highest from early to midgrowing season. Fertilization near seeding time proves very effective for most crops. Fall-planted grains like winter wheat benefit from fall nitrogen followed by spring topdressing strategies. Application of soluble mineral fertilizer such as ammonium nitrate avoids heavy rainfall periods where loss occurs rapidly.

  Liquid versus solid forms offer different advantages depending on farm needs. About ninety percent of fertilizers applied globally appear as solids. Most widely used solid inorganic fertilizers include urea, diammonium phosphate, and potassium chloride. Granulated or powdered forms dominate commercial availability. Liquid fertilizers comprise anhydrous ammonia aqueous solutions of ammonia or urea. These concentrated products may be diluted with water to form concentrated liquid mixtures known as UAN. Advantages of liquid fertilizer include more rapid effect and easier coverage. Foliar fertilizers apply directly to leaves reducing total amounts needed while achieving high efficiency. This method almost invariably applies water-soluble straight nitrogen fertilizers especially for high-value fruit crops. Controlled-release fertilizers release nutrients gradually into soil over controlled periods ensuring sustainability.

• 6. Policy And Future Sustainability

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  In Europe problems with high nitrate concentrations in runoff face regulation through the European Union's Nitrates Directive. Farmers within Britain manage land more sustainably using catchment-sensitive farming techniques. High concentrations of nitrate and phosphorus in US drainage water classify as nonpoint source pollutants regulated at state level. Oregon and Washington maintain fertilizer registration programs listing chemical analyses online. Carbon emission trading and eco-tariffs affect production costs and final prices for farmers. In China regulations control nitrogen fertilizer use in farming operations. Chinese governments began partially withdrawing fertilizer subsidies including transportation and electricity usage in 2008. Price increases forced large-scale farms to optimize existing supplies rather than rely on cheap inputs.

  The United States Department of Agriculture announced a new two hundred fifty million dollar grant program in March 2022. This initiative promotes American fertilizer production independent of dominant suppliers. Innovative production techniques aim to jumpstart future competition domestically. The Russo-Ukrainian war caused strong increase in energy and mineral fertilizer prices highlighting need for greater autonomy. EU countries provided specific support to farmers and producers under amended Temporary Crisis and Transition Framework. Funds generated from market revenue caps on certain electricity generators supported national schemes. Production of these fertilizers contributes around five percent of anthropogenic greenhouse gas emissions globally. Nitrous oxide emissions between 2007 and 2016 reached seven hundred million tons of carbon dioxide equivalent.