Phosphates are used in fertilisers also. They are products formed by the replacement of some, or in some case all, of the hydrogen of a phosphoric acid by metals. Depending on the quantity of hydrogen atoms that are replaces, the resulting compound is referred to as a primary, secondary or tertiary phosphate. Phosphates are important to metabolism in both animals and plants. Primary calcium phosphate (Ca(H2PO4)2) is the ingredient of numerous plant fertilisers. When it is used as part of a fertiliser, if can be washed into waterways by the rain and pollute rivers and streams in the way mentioned above. Potassium (K) has several general functions. These mainly consist of the carbohydrate and protein synthesis that are necessary for the activation of numerous enzyme functions. Potassium, for this reason, is important during most stages of growth. When it comes to dispersion, organic fertilisers have a harder time because they’re compressed into large clumps. Breaking up these lumps may be done to spread out the fertiliser further. However, one piece may have an unbalanced amount of nutrients. Inorganic fertilisers excel at this because they are easily distributed, since they are smaller and granular. They also contain the same proportion of nutrients per granule. 3
The drawback with being dispersible is the capability to still be able to be moved around after it has been scattered across the fields. As mentioned above, rainfall is easily able to whisk away the inorganic fertiliser and take it to a nearby water source.
Scientists are working on a means to get plants to create their own source of nitrogen, which would mean farmers could dispense with using inorganic nitrogen fertilisers, which also in turn would mean less eutrophication in nearby water sources. This operation to genetically engineer plants to make their own source of nitrogen is also a cause for concern because it plans to use the herbicide (plant killer) 2,4-D – 2,4-Dichlorophenoxyacetic acid (C8H6Cl2O3) is usually used in the control of weeds such as the broadleaf. 2,4-D is a herbicide which has acute gaps in the research fields concerning human responses. It has been classed as ‘moderately hazardous’ due to experiments proving it to have a LD50 title. (LD50 standing for Lethal Dose, 50%) 5 / 7
Research shows that the nitrogen input into the soil by fertilisers has become increasing irregular. Farmers nowadays tend to add fertiliser for the sake of producing a larger yield. Scientific studies have proven that nitrogen-containing fertilisers are being over-used at times where they are no longer needed. This usually leads to eutrophication of water ways. The application of nitrogen when crops do not need it gets absorbed by the pests in the soil. Pests include plants, bacteria and other organisms. The increase in nitrogen allows them to reproduce/replicate at a faster rate near the plant, thus becoming a parasite.
Organic fertilisers are intrinsically different in many ways, a lot of them mentioned above. But one of the most crucial ways it is different to inorganic is that is requires the presence of soil micro life, such as different bacteria and fungi, to break the fertiliser down and convert them into the chemical form that is usable by the plants. 6Inorganic fertilisers do not just feed the plant. It can also feed the soil microbes in addition to the crop/plant in question. The ammonium in the fertilisers created chemically can be a hazard to some of the soil’s micro life, for instance earthworms. Chemists and researchers are inventing something called ‘biobeads’ which can be placed in moist soil. Bacteria convert the ore into bio-available phosphates which then slowly gets absorbed by the soil. This reduces the chances of excess phosphates leeching into rivers, lakes and other forms of groundwater. The final and more financial impacting effect of all is that chemical fertilisers can be produced on demand; where as organic fertilisers have to be produced naturally over the course of a few months. 2
Should an argument be raised as to which are the more beneficial with the least negative effects on the environment, Organic Fertilisers would be my choice. As stated clearly before, Fertiliser run-off can cause water to become eutrophic (nutrient rich body of water). While this is a common and lethal blow to the environment, it is far more popular with fertilisers whom have had nutrients artificially implanted within the actual fertiliser. Since organic fertiliser contains a low amount of this (some having been ingested through animals), they would cause the soil to be less eutrophic. In addition, the weight of organic fertiliser will reduce the run-off due to the bulk of it.8
However, in terms of product output of the cereal crops, Inorganic fertilisers are more efficient due to the fact that organic fertiliser cannot be created in the quantities needed to fertilise the crops needed to feed our ever-growing population, and although inorganic has several major hazards to its use, scientists are always coming up with different ways to counteract the leeching and poisoning which is a result of natural events such as rainfall. This combined with individual scientific research is increasing the popularity of inorganic fertiliser.
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List of Sources
1 - http://en.wikipedia.org/wiki/Fertilisers - Internet
2 - http://www.westsidegardener.com/guides/whyorganicfertilizer.html - Internet
3 - http://www.ballance.co.nz/images/pdfs/handbook/section6.pdf - Book (Typed up book)
4 - Longman Study guides – Biology – by Alan Cornwell and Ruth Miller (page 237. The quote next to the 2nd paragraph about nitrates) - Book
5 - http://www.newscientist.com/unpwlogin.ns;jsessionid=OKKNOJGELGPP - Journal
6 - http://www.newscientist.com/article/mg16321972.200.html - Journal
7 - http://www.pan-uk.org/pestnews/Actives/24d.htm - Website concerning 2,4-D
8 – Biology for schools and colleges – Colin Clegg Page - 322 (Excess nutrients that cause eutrophication) - book
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