The Effect Of Fertilisers On The Environment
The Effect Of Fertilisers On The Environment.
The use of fertilisers and their effect on the environment is a much-debated issue. There are positive and negative effects which must be considered throughout this essay. It is difficult to say which argument outweighs the other, and whether usage should be continued, abolished or more heavily controlled.
'Fertilisers are chemicals given to plants with the intention of promoting growth; they are applied either via the soil or by foliar spraying' (Wikipedia, 2005). Varying proportions of the three major plant nutrients, nitrogen, phosphorus and potassium are used as well as other chemicals in inorganic fertilisers. Organic fertilisers can be used to 'improve the production of new biomass in ... ecosystems' (Fullick, 2000). Manure was once the most popular fertiliser, as 'many UK and US a farmer's were 'mixed' farmers' (Fullick, 2000) producing livestock and crops, and is still a predominant organic fertiliser. 'Crop rotation' (Fullick, 2000) is another method of Organic Fertilisation. This method is based on the principle that one crop should not be grown in the same soil for one year. Organic fertilisers are more predominant in developing countries, which cannot afford the more expensive inorganic chemical fertilisers.
Positive effects of fertilisers on the environment are not as well-known as the negatives, due to media hype. However, they may be just as significant. Fertilisers aim to meet the following agricultural aspirations:
* to maximise productivity in terms of yield per unit area.
* to increase the proportion of crop available for human consumption. (Bowsher, 2004)
Fertilisers will undoubtedly be needed as the world population 'has been predicted to reach 8.3 billion people by 2025' (Bowsher, 2004). But, will the effect on the environment due to increased usage, caused unprecedented problems? .
As fertilisers promote the growth of plants via maintaining adequate levels of nutrients in the soil, they often enhance the habitats of many species of animals, birds and insects. Fertilisers therefore provide 'sustenance and shelter' (Royal Horticultural Society, 2002), which may be heavily needed in damaged ...
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* to increase the proportion of crop available for human consumption. (Bowsher, 2004)
Fertilisers will undoubtedly be needed as the world population 'has been predicted to reach 8.3 billion people by 2025' (Bowsher, 2004). But, will the effect on the environment due to increased usage, caused unprecedented problems? .
As fertilisers promote the growth of plants via maintaining adequate levels of nutrients in the soil, they often enhance the habitats of many species of animals, birds and insects. Fertilisers therefore provide 'sustenance and shelter' (Royal Horticultural Society, 2002), which may be heavily needed in damaged or unhealthy ecosystems.
The use of fertilisers is sometimes referred to as 'The Green Revolution'. Amazingly, some scientists suggest fertiliser use may have prevented 'even worse' global-warming. Fertilisers allow farmers to increase their crops yield. Therefore, 'huge areas of rainforest' (New Scientist, 2004) were maintained as farmers did not need to remove them for crops. This in turn reduced carbon dioxide emissions, preventing global warming.
The production of fertilisers is named the Haber-Bosch process (Wikipedia, 2005) and uses approximately 1% of the total energy consumed by the entire global population. It produces the ammonia to create Ammonium Nitrate, a prominent fertiliser in use. The process emits carbon dioxide into the atmosphere which may be damaging the whole world environment by adding to Global Warming.
'Diffuse pollution' (www.environment-agency.gov.uk) is a major negative effect of fertilisers. Agricultural activities are a major contributor to diffuse pollution, including fertilisation of crops. Nitrogen and Phosphorous cause the majority of diffuse pollution, as Potassium is 'taken up by plant roots rapidly' (www.agric.nsw.gov.au) and therefore, minimises the chances of potassium being leached into the surrounding environment.
Diffuse pollution and leaching of fertiliser chemicals and organic fertilisers such as manure, as well as 'a third of nitrogen applied (as fertiliser) to farms [which] emerges as animal waste' (www.newscientist.com) often results in the most common negative effect; Eutrophication. When fertiliser chemicals such as nitrogen and phosphorus, and manure leach into rivers, streams and ponds. 'they provide nutrients for the water plant, algae and photosynthetic bacteria present in the water'. (Fullick, 2000) These products will then induce and encourage growth in algae and other water plants on a mass scale. The death of the increased number of plants and bacteria attracts the 'decomposers'. The decomposers then use up much of the oxygen in the water, depriving other organisms from fish to other bacteria, which then die. The situation gets worse and worse and often spreads until all life in the water system is lost. It is a vicious cycle.
Eutrophication is predicted to 'double or triple' (New Scientist, 2004) in the next 50 years. The loss of biodiversity would be unprecedented. The effect of Eutrophication has already been noted by the United Nations. According to a United Nations agency in the summer of 2003 'every sea creature across an area twice the size of Wales was asphyxiated by severely depleted oxygen levels'. (www.guardian.co.uk) This effect occurred in the Gulf of Mexico, and similar sites have been named "dead zones". There are around 150 different sized areas in the world oceans. The problems caused by Eutrophication are often irreversible.
Crops which use fertilisers are an abundant food source for animals, birds and some insects due to the increase in yield of edible products. However, this seemingly positive effect can become negative as, due to the increase 'grazing pressure' (Sneyd, 2004) and increase in predators, weaker species will die out and therefore the food chain will decrease.
Mixed farming provided many animals, birds and plants with an environment and habitat with many different food sources. However, many farmers had no need for the manure which arable farming produced with the introduction of inorganic fertilisers and therefore, decided to use the arable land as crops as this was more economically viable. Therefore, while some species main food source thrived, others food sources decreased resulting in loss of species.
Increased human activity on crops to deal with the increased crop yields (due to fertiliser usage) will also be damaging to the environment, as many animal and bird species may be forced out of their natural habitat. This will reduce abundance of life in the environment and could be damaging to the local food chain.
There are positive (mainly economical) and negative (mainly physical) effects which the use of fertilisers induce. Undoubtedly, the economic stability of many developing countries rely on a strong agricultural abilities. Fertilisers create and increase such abilities. However, the negative effects, such as Eutrophication and habitat loss, are damaging the environment around such countries, and many others. It is difficult to say which argument outweighs the other.
The fact is, some countries and their people, would struggle to survive without organic and inorganic fertilisers, but the effect fertilisers are having on the environment may be damaging enough in future years to destroy those countries and people.
BIBLIOGRAPHY
* Bowsher, C et al. September 2002. Biological Sciences Review: Volume 15 - Number 4.
* Fullick, A. 2000. Heinemann Advanced Science Biology - 2nd Ed. Heinemann.
* http://www.agric.nsw.gov.au/
* http://www.environment-agency.gov.uk/yourenv/eff/...
* http://www.guardian.co.uk/waste/story/0,12188,1180697,00.html
* http://www.newscientist.com/
* New Scientist Magazine. 21 April 2004. Issue 2287.
* Royal Horticultural Society. November 2002. Conservation & Environment Guidelines: Manure and Fertilisers.
* Sneyd, J et al. April 2004. Biological Sciences Review: Volume 16 - Number 4.
* Wikipedia. 2005. http://en.wikipedia.org/wiki/fertilisers
