The Dangers of Over Fertilizing

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The Dangers of Over Fertilizing: Introduction: The detrimental effects of artificial fertilizers in the agricultural sector are well documented and wide spread. Combined with nutrients from concentrated sewage and nitrogen oxides released by the burning of fossil fuels, the use of artificial fertilizers in industrial agriculture contributes to nutrient pollution, which is becoming a global problem. This type of pollution is known as non-point source pollution in the literature. This means that
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  The Dangers of Over Fertilizing:Introduction:The detrimental effects of artificial fertilizers in the agricultural sector are well documented and widespread. Combined with nutrients from concentrated sewage and nitrogen oxides released by theburning of fossil fuels, the use of artificial fertilizers in industrial agriculture contributes to nutrientpollution, which is becoming a global problem.This type of pollution is known as non-point source pollution in the literature. This means that it isnot coming from any particular factory or any particular source, but is a general environmentalcontaminant. The most common compounds used as artificial fertilizers in the agricultural sector arenitrogen and phosphorus compounds, both of which provide nutrients used by plants. On grainfarms, these artificial fertilizers are usually applied either in the form of tiny solid pellets when fieldsare seeded, or in liquid form as anhydrous ammonia before planting.What is happening is that through using large amounts of artificial fertilizers we are changing thenitrogen cycle through which nitrogen and nitrogen compounds natural cycle between soils, plantsand the atmosphere. The combination of artificial fertilizers, concentrated sewage and fossil fuel useis raising general nutrient levels beyond their natural levels, or beyond their optimum range. In thecase of fertilizers, excess nutrients are often washed out of fields and into rivers, lakes, seas andinto groundwater. This is especially true when there are heavy rains in spring, before the crops beginto grow, and use up the nutrients in the fields.The Ecological Effects of Excess Nutrients:1. Human Health Effects:Human health effects are largely due to the contamination of ground water or other drinking waterwith elevated levels of nitrates. According to Danielle Nierenberg (2001), this can lead to bothelevated risks of miscarriage for pregnant women and to blue-baby syndrome. Also known asmethemoglobinemia, blue-baby syndrome results from the fact that human infants' digestive systemsconvert nitrate to nitrite. The problem is that nitrite blocks the blood's oxygen carrying capacity. Theresult is suffocation and death. Ruminant livestock such as cattle, sheep and goats, whose digestivesystems behave in a similar way, are also vulnerable. Over 3,000 babies have died from blue-babysyndrome world wide since 1945 (Sampat 2000).2. Effects on Vegetation:  Just as too few nutrients are bad for plants and limit their ability to grow, too much is alsodetrimental. As Payat suggests, too many nutrients actually weakens the immune system of plants,making them more vulnerable to pests and disease (2000). The immune systems of plants are verydifferent from those of animals, being based upon the production of a number of chemicals toneutralize toxins and disease (instead of killers cells and antibodies). Excess nutrients interfere withthe natural production of these chemicals and, as Chris Bright describes it, can lead to a kind ofbotanical equivalent of AIDS (1999).Excess nutrients can also reduce cold hardiness in some species, and restrict the uptake of waterand soil nutrients in others (Nierenberg 2001).3. Effects on Surface Water:Besides the risks to human health associated with groundwater pollution,nutrient pollution alsoaffects surface waters and the health of the wildlife they contain.A. Red tide organisms are toxic forms of algae in the ocean. Being a type of plant, excess nutrientscan lead to an explosive growth in the population of such species to the extent that their toxins leadto fish kills.B. Eutrophication events can lead to fish kills as well. Besides red tide organisms, nutrient pollutionof water bodies also promotes the growth of algae in general. Algae, after all, are merelymicroscopic forms of plant life which live in bodies of water, and they respond to an increase innutrients in the same way that a crop of wheat or corn does-by growing more quickly.If nutrient levels from agricultural run-off, or from high levels of organic wastes or sewage moregenerally, become too high, they can lead to a process known as eutrophication. Eutrophicationhappens in two stages:First, increased nutrient levels cause an explosive growth of algae in bodies of water.Second, as these unnaturally high populations of algae die and begin to decay, their decayconsumes all of the oxygen content in the water, killing fish and all other oxygen dependent species.The process is rather paradoxical, since plants give off oxygen, but the process of decay consumesmore oxygen than they give off. There have even been documented cases of eutrophication eventsin coastal waters in the ocean after heavy spring rains cause large amounts of nutrients to bewashed into the sea. Nutrient pollution also contributes to the decline of corral reefs, which are themost ecologically diverse marine ecosystems (as rain forests are for terrestrial ecosystems).Conclusion:  Nutrien t pollution is a global problem. The effects on forests, water and fish are particularly central.The use of excessive amounts of artificial fertilizers in agriculture is one of its main causes.Essentially, our reliance on artificial fertilizers is over-taxing the nitrogen cycle, leading to anincrease in the amount of nitrogen compounds in the biosphere, well beyond their optimum range.Combined with fossil fuel combustion and concentrated sewage, this creates a global problem. Inthe agricultural sector, however, we can kill two birds with one stone. This can be accomplished byeliminating artificial fertilizers and replacing them with human and animal wastes. After all, sewage,or manure is a natural fertilizer, and is only problematic when concentrated in a centralized manner,or over-applied.If we were to separate human sewage from the industrial and residential chemicals which we alsoflush down the drain, it would pose no danger as far as contaminating soil or the food grown from it.The keys, then, are: 1. to stop thinking of sewage as waste and, 2. to stop thinking of agriculturalfertilizer as something which must be manufactured for a profit.After all, in nature animals provide such nutrients to the soil for free. Learning to reproduce thatprocess would go a long way to solving the problem of nutrient pollution which our global societyfaces.References, additional reading:Chris Bright (1999) The Nemesis Effect, World Watch, May/June.Danielle Nierenberg (2001) Toxic Fertility, World Watch, March/April.Payal Sampat (2000) Groundwater Shock: The Polluting of the World's Major Freshwater Stores, World Watch, January/February.
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