The world’s cultivated lands are limited and it is sad that only eight billion people can be sustained by the present ability of world food production. Nowadays food shortages in Less Developed Countries, especially African countries have deepened over the few decades and the United Nation has speculated that the world population will increase to 9.2 billions by 2050. Unless we take certain measures even more people will starve to death in the future. Although some researchers have advocated that we need to utilize more artificial fertilizers to catch up with the fast growing demands for food, there have been a number of disputes over this subject due to the negative consequences which can stem from its use and its impacts on people and the environment. Therefore, in this essay I would like to discuss whether we should produce more artificial fertilizers in order to produce more food or not.
Why have farmers in the present time relied on use of artificial fertilizers rather than organic fertilizers?
Plants need numerous different chemical elements in order to grow and thrive. The biogenic chemical elements which are particularly important for the growth of plants are nitrogen, phosphorous and potassium, and they are needed in large quantities (see Appendix A). However in reality as generally they accumulate in soils in the process of microorganisms decomposing dead of plants and wastes of animals sources of these macronutrients are limited naturally, so their availability in soils tends to be so low that they can become deficient very often due to the difficulty of natural replacement. As I have noted before, these three elements are really vital in order for plants to grow and their deficiency in soils can be a great limitation on the growth of plants.
Although there are still many environmentally friendly ways to solve this problem, such as the use of animal manures, heap composts and leguminous plants, most farmers have nowadays relied on artificial fertilizers, mainly supplying just nitrogen, potassium and phosphorous. This is because artificial fertilizers are economically much more advantageous than organic fertilizers. In case of organic fertilizers, until its effect becomes observable bacteria convert various forms of the three vital macronutrients to something different so that plants can actually take in the nutrients (Eg, nitrogen ==> nitrates ). Therefore it takes more time to grow plants and its efficiency is comparatively low. By contrast as artificial fertilizers are generally comprised of nutrients themselves plants can take them in directly without any time-consuming processes such as, decomposition, nitrification and nitrogen-fixation.
Therefore it enables famers to grow more plants efficiently at a period of time. Information on the amount of nutrients and the exact elements in organic fertilizers such as manure is not readily available and it often results in adding nutrients which do not really meet with plants’ need and can cause a serious damage to them. By contrast, when you apply artificial fertilizer onto the soil you know the kinds and amounts of the elements it contains, and this allows you to be more precise in meeting a plant’s nutritional needs and prevent them from adding other chemical elements which are not wanted by plants.
Moreover although effect of organic fertilizers is hugely affected by the temperature of the soil and other natural factors, the effect of artificial fertilizers is not likely to be subjective to environmental changes. This is because artificial fertilizers can be directly taken up by plants without biological processes of microorganisms in the soil. Essentially, use of artificial fertilizers enhances the efficiency of agriculture and the productivity (crop yield) in comparatively comfortable and precise way rather than organic fertilizers. That is why more farmers have tended to prefer to use artificial fertilizers than organic fertilizers.
What is the Haber Process and are its disadvantages?
The Haber Process has been today the principal method of producing ammonia which is the most vital substance to make fertilizers, and it has contributed to agricultural intensification worldwide. In the process, ammonia is manufactured from two raw materials hydrogen and nitrogen in the following reversible reaction:
Nitrogen + Hydrogen <=> Ammonia
N2 + 3H2 <=> 2NH3
Hydrogen is made from natural gases in combustion reactions and nitrogen is made in a large scale in the fractional distillation of liquefied air. Hydrogen and nitrogen gases are mixed together in the proportions one part nitrogen to three parts hydrogen. The mixture goes into the reaction vessel and is compressed to a high pressure (200 atmospheres) and temperature (400?) in a closed system. Then the mixture of gases from the reaction vessel is cooled down. The ammonia which has the lowest boiling point liquefied and removed separately, the unreacted hydrogen and nitrogen gases are then returned to the reaction vessel to undergo further reaction through . Afterward the ammonia produced in the Haber Process will be reacted with other different substances so as to produce artificial nitrous fertilizers. For example, the ammonium is oxidized into nitric acid and then it is reacted with ammonium gases to form ammonium nitrates, which is one of the present-day most-used nitrate fertilizers in the world (the chemical formula is shown below):
Ammonia + Oxygen ==> Nitric acid + Water
4NH3(g) + 8O2(g) ==> 4HNO3(aq) + 4H2O(l)
Nitric acid + Ammonia ==> Ammonia nitrate
HNO3(aq) + NH3(g) ==> NH4NO3(aq)
In order to produce ammonia as economically as possible, following the Le Chatelier’s Principle the best temperature and pressure are used in the Haber Process and also iron oxides are utilized as a catalyst. Therefore both productivity and efficiency of the process are truly high and it is even said it is impossible to substantially develop them even further. However although it seems to be a perfect manufacturing process, on the other side it has some disadvantages in reality.
If manufacturers are not careful, some processes can damage the environment and be a danger to people’s heaths. In order to ensure that these negative consequences do not occur the following environmental consideration are necessary: safe disposal of waste, design of plants to make it little seen and unobtrusive, reduced gas emissions, periodic shut-down for safety checks, warning and evacuation procedures for local communities and schools, reduced noise levels and slam shut valves in emergency. However since some of these factors can be really costly, there have been some cases of manufacturers avoiding to take care of them, which threatens local community and results in air pollution and destruction of ecosystems.
On the other side of the coin, price of artificial fertilizers has been also cited as a problem. Although the Haber Process is efficient and effective method to produce ammonia, it is relatively expensive and so the artificial fertilizers. Most farmers in MEDC (More Economically Developed Countries) can generally afford for it, but current financial standard of people in developing countries, particularly ones in South Africa has not reached sufficient level to buy them. In 2002 thousands of people died Malawi, a country of South Central Africa due to food scarcities. A government report suggests that more than 430,000 tones of maize will be needed to avert the second food shortage in three years and this possibility is unavoidable unless they enhance the crop yields rapidly by intensifying the use of artificial fertilizers. However, currently this seems to be unachievable for both the locals and the government.
What are the negative effect of artificial fertilizers on people and the environment?
As I noted before artificial fertilizers have contributed to the world food production and in effect 40% of world’s population are alive thanks to it. However, it has many negative impacts on both the environment and people.
Certainly artificial fertilizers enable you to grow more plants efficiently at a period of time as they are made up of pure nutrients and plants can take them in directly without any biological processes in the soil. However the effect can last for one to two years in effect. Many biologists have actually suggested that this is because application of artificial fertilizers reduces the number of microorganisms in the soil because of lack of food and destroys the ecosystem. Microorganisms in soils play a vital role in not only decomposing organic matters but also supplying soils with air, spaces and heats by respiration and other activities.
This naturally cultivates soils and makes them environmentally much easier for plants to send out their roots in. In essence, if microorganisms disappear from the soil where they have cultivated, due to application of artificial fertilizers, the soil becomes much harder which is difficult for plants to put down their roots, and so plants cannot take nutrients in efficiently. Therefore, as a result one or two years after applying artificial fertilizers crop yields start to decline and even it becomes difficult to grow plants in the soil anymore at the end. Although still famers can keep a high productivity by applying a huge amount of fertilizers onto the soils it is unavoidable for this to eventually contribute to reduction in crop lands, considered one of the most important elements so as to overcome the possibility of future world food shortages.
Nitrogen-nitrates, one of the most prevalently used substance of artificial fertilizers has a high solubility in water. Therefore, if farmers use excessively or apply them on the soil before a period of heavy rain, it can be washed out through the soil into a river or a lake. Then due to the accumulation of excess amount of nutrients (eutrohication) algae start to bloom dramatically which causes fluctuation in the concentration of oxygen in the ocean and result in killing fish or other aqueous living forms. Actually in Jamaica which is a truly agricultural country, over-use of artificial fertilizers has often caused eutrophication and this has resulted in smothering coral reefs and destroying the marine ecosystem of the sea around the island. Surprisingly according to research, this has nearly collapsed the entire interdependent relationship in the marine ecosystem of the island and according to WTO (World Tourism Organization), the existences of 20 percent of all aqueous organisms have been threatened.
When ammonia nitrates enter our drinking water, it can also harm people’s health. As ammonia nitrate is one of existing various forms of nitrogen-nitrates (NO3-N), it can be transformed to nitrogen-nitrite in the human digestive system through chemical reactions with digestive enzymes. The nitrites can oxidize iron molecules in hemoglobin of the red blood cells to form methemoglobin, which deprives the oxygen-carrying ability from hemoglobin. Most humans over one year of age have the ability to convert methemoglobin back to harmless oxyhemoglobin. However in the bodies of infants under six months of age as the enzyme systems for metabolizing methemoglobin are incompletely developed, methemoglobinemia (sometimes referred to as blue-baby syndrome), in which blood lacks the ability to carry sufficient oxygen to the individual body cells, causing the veins and skin appear blue can occur.
According to The U.S. Public Health Service, the U.S. Geological Survey held during the period from 1970 to 1992, found that 9% of the tested private wells exceeded the recommended limit of 10mg/l nitrate-nitrogen and there were 278 occurrence of methemologlobinemia, 39 infants actually died in the same duration. And in fact this was due to the leakage of nitrogen fertilizers from agricultural lands. Since then a strict limitation has been set on the concentration of nitrogen-nitrates for public waster system in the U.S. and the number of victims of drinking-water contamination caused by artificial fertilizers have diminished. However, according to WHO(World Heath Organization) it is really difficult to search out where the nitrogen-nitrates leached out from and due to the rapidly increasing demands for food in the USA it is also problematic to strictly regulate use of artificial fertilizers.
These two factors make it nearly impossible to overcome the health hazard which can stem from the use of artificial fertilizers. Actually even in the present days there have still been some cases of infants dying due to methemoglobinemia. On the other hand, a latent cancer risk from nitrogen-nitrates in water and food has been reported by some biochemists. They say there is a possibility that nitrates react with amines or amides in the human body to form nitrosamine known as a cancerous substance. In effect, there is an apparent correlation between where intensive agriculture has been flourished, which utilizes much more artificial fertilizers and where there are a number of patients suffered from cancer.
Through this essay, I have discovered that in contrast with the fact that most famers have relied on artificial fertilizers considering its economical positive side, it has numerous negative impacts on both the environment and people’s heaths and many negative consequences have already occurred in reality. I have also learnt that although the Haber Process which is the principal manufacturing method to produce fertilizers, has such an incredible efficiency and effectiveness this has concurrently intensified environmental destruction and kept the price of artificial fertilizers so high that many people living in LEDC cannot really afford it and suffer from food shortages due to low crops yields. Considering these points, I do not believe that intensifying production of artificial fertilizers is the best way to cope with the fast growing demands for food. It is apparent that there is a high possibility of exacerbating the problems by producing more artificial fertilizers. However taking into account the fact that 40% of world’s population are alive thanks to artificial fertilizers, at least we need to maintain the current quantity of its production.
Following this, what can we do to catch up with the continuously swelling needs for food so as to avert the possibility of worldwide scarcity by 2050? Specifically there are two ideas. The first one is to make crops which can grow in deserts, cold districts and soils which contain a lot of salt. By doing this, we can convert grounds in which we could not cultivate, to agricultural lands. The another idea is to enhance the productivity of crops itself. Whatever happens the world population cannot grow by three times bigger than the current population. Therefore if we could increase the crop yields per a unit of area by three times it would be enough. In case that food is over-produced this way we can just use them as bio-fuels. In order to make these two ideas reality we will need to concentrate on advancement of genetic engineering and invest in the area. I believe that this is the realistically most reasonable way to overcome the world food shortages in the near future and the mission on 21st century’s scientists.
January 9, 2018
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