Human Influences on the Environment

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Greenhouses provides right conditions for plants to grow for several reasons:

·         The transparent material allows sufficient natural light in for photosysthesis during the summer months and gives a "longer day" during the winter.

·         Short wave radiation entering the greenhouse becomes longer wave radiation as itreflects off the greenhouse's surface. They cannot leave as easily so greenhouse'sheat up fast.

·         Burning fuels to raise the temperature which also produces C02 and Water Vapour.

·         The Water Vapour produces a moist atmosphere and so reduces water loss by transpiration.

·         In addition, growing plants in a hydroponic culture provides exactly the right amount of mineral ions for the specific crop being grown.

Fertilizers on the farm - Organic and Inorganic.

·         Organic contains farmyard manure whuch returns some nitrogen in the soil. But only can replace a small proportion.

·         Inorganic contains inorganic compounds such as Nitrates. Lots of farmers use this because it can replace all the lost ions. It can lead to problems like Eutrophication.

Pests are organisms which reduce the yield of crop plants. Pests can be controlled in a number of ways. Chemicals called pesticides can be used to kill them or by usingbiological control. With Pests it causes economic damage.

·         Pesticides are poisonous, so theymust be used carefully too keep it below the "safe level". They also harm other wildlife as well. Some do not work as some pests will be resistant. Through chance of mutation and natural selection. This makes some pesticides useless and cause environmental damage as well.

·         Biological Control is an alternative, it means using other organisms to reduce numbers of pest.

·         The helpful organisms could be predators and parasites (some flies lay eggs


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