Pesticideby Razaan Abakar | 03-10-2017 21:21 |
|---|
 Organic Farming: Conventional farms rely on an array of synthetic pesticides to kill weeds, disease causing fungi, and harmful insects. These pesticides are manufactured by chemical processing petroleum, natural gas, ammonia, and a number of other raw materials. They include active and inactive ingredients, both of which can be highly toxic and long lasting. Organic farmers typically use pesticides primarily derived from unaltered plant, animal or mineral substances in which the active toxic ingredient breaks down rapidly to become nontoxic after being applied to the crop. Pyrethrum, a substance extracted from chrysanthemums, a variety of soaps, and oil from the need tree are among the insecticides used by organic farmers, Bordeaux mix, a combination of calcium carbonate and copper, is used by organic farmers to control disease causing fungi. Air Pollution Several pollutants attache the ozone layer. Chief among them is the class of chemicals known as pesticide methyl bromide. Soil Management: The effectiveness of a pesticide as well as the hazards of harmful residues depend largely on how long the pesticide remains in the soil. For example, DDT, a chlorinated hydrocarbon, has a half life of three years in cultivated soils, while organophosphorus insecticides persist for only days or months. Chlorinated hydrocarbon persist longer in soils having a large amount of organic matter, although more of the chemical must be applied to these soils to kill pests. Insecticides persist longer if worked into the soils than if left on the surface. Eventually, all pesticides disappear because of evaporation and vaporization, leaching, plant uptake, chemical and microbial decomposition, and photodecomposition. Pesticides effect on animal life and also cause water pollution. Source: Microsoft Student with Encarta Premium. |
