Ecology And Environment

Biological and Biotechnical Agriculture



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Issues concerning biological and biotechnical agriculture - including pesticides

The use of inorganic chemicals as pesticide, herbicides and fertilisers in agriculture has become a more and more controversial topic over the last decade due to the growing demand and popularity of organic products in both localised and mainstream markets, organic-food sales grew 16% from 2004 to 2005 and continue to rise (1) and the continuous question and research into the environmental impacts of said chemicals in a direct area and the negative effects. The intensification of chemicals as they are reapplied, concentration of farmland as there are fewer but larger farms and the specialisation, the reduction in the diversity of the crops grown, are all key factors in to problems associated with using agricultural chemicals.

The serious (but very different) environmental problems caused by the different uses of inorganic substances did not become apparent until the mid-1960s and early 1970s (2) but a lot later on, in 1993 it became clear the effect was extremely bad when there were over 2500 Environmental Pollution Incidents in farms alone in the UK all due to the use of fertilisers and pesticides.

Pesticide chemicals, insecticides, appeal to farmers and other users as they are easy to store and can be easily applied in a light spray. This is all very economically simple to the cultivator but the use of these toxins also decreases biodiversity in the soil which allows for higher water capacity. Not using them results in higher soil quality. This helps increase yields for farms in drought years where there is less rain. For example, during drought years, organic farms in the USA have been found to have yields 20-40% higher than conventional farms (3)

The indiscriminate trait of most pesticides can also lead to complications as any non-target organism can also be effected; a decline in the pollinators in an area has also been proved. This is a problem not only as an impact on the environmental biodiversity but also the crop yield itself, lower rates of pollination can be devastating to some selected plants. Chemicals may also pass into the food chain and accumulate in greater quantities with the larger predators. This is due to the consumption of many smaller organisms, each carrying a small amount of the toxin. (4). This is a cycle effect as the predators which are eating the insects are in fact aiding the plants growth (they are therefore known as a biological control, which is an alternative to pesticides) but this natural pest killer is being killed itself because of the chemicals used.

The use of chemicals, particularly insecticides and nitrates (a fertiliser) has on very important and very dangerous final effect: leeching leading to eutrophication. The contamination of the water ways by these chemicals means that they cannot only effect the local area of a farm but can also be transported and pollution can build up. Leaching is the way in which the chemicals effect the ground water of the land and are transported into the river, stream or lake centred of the catchment area. In areas of high agricultural development this has a very detrimental effects.

Eutrophication is one of these. Eutrophication is a process whereby water bodies, such as lakes, rivers or streams receive excess inorganic toxins that stimulate excessive plant growth (e.g. algae). This algal bloom reduces dissolved oxygen in the water when dead plant material decomposes and can cause other organisms to die (5). It can be argued that the dilution of the chemical in a water system mean that the concentration is so low that there is no real damage caused, but repeated application of the substance to the land means higher levels in the water that can lead to such effects as eutrophication. In the UK, pesticide contamination of drinking water and river ways in monitored by the National Rivers Authority.

But even with all these problems being proved and sustained more and more with each research project, farmers continue to apply high levels of pesticide, to which it has in fact been proved insects become immune and highly concentrated fertilisers, although this has been shown to damage the osmotic barrier of plants root system. It is slowly becoming clear however that perhaps "do-nothing" farming is that way to go. Masanobu Fukuoka, a Japanese farmer and author of "the One-Straw Revolution" is just one of the many new radical farmers or spare the expense and work their land (or not work) by the four major principles: No cultivation (that is hoeing, ploughing etc.), No fertiliser, No weeding and No pesticides (6).

This may seem a controversial idea (which is doomed to failure) but the monitored yield of natural "do-nothing" farms have, after an average development time of 5 years not only did the yield begin to match the rate of those obtained using modern farming techniques, but in some cases actually began to exceed them.

Bibliography 1.Ken Meter, May 5th 2006, http://gristmill.grist.org/story/2006/5/5/12518/15989 2.BATH, Environmental Science, Second Edition, Kevin Byrne 2001 3.Johnston, A. E. (1986). "Soil organic-matter, effects on soils and crops". Soil Use Management 2: 97-105. http://en.wikipedia.org/wiki/Pesticide#On_the_environment 4.LETTS, AS & A2 Biology Guide, New Edition, John Parker 2005 5.http://toxics.usgs.gov/definitions/eutrophication.html
6.HARPER, 365 Ways to Change the World, Micheal Norton 2005

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