Agricultural Science


Challenges on the Population

Examples of Challenges:

  • Population growth

  • Climate Change

  • Energy crisis requires more land to grow biofuels

  • Changing diets

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Haber Process

Haber Process

  • It Produces Ammonia

  • Used to make Fertilizers

Why is it so important?

  • The haber process has increased the productivity of field four fold

  • More food has allowed the population to grow

  • 1.6 billion in 1900 to 7 billion today

  • Nearly 80% of the Nitrogen in human bodies originated from the Haber Process

  • Haber Process consumes 3-5% of the world’s natural gas

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Use of fertilisers/Herbicides/insecticides

Using fertilisers - can cause fish to die

Using Herbicides- can kill plants that animals need for food

Using insecticides- can kill useful animal

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Process of Eutrophication:

Fertilisers containing phosphates and nitrates are washed into lakes

Algae in the lake use the phosphates and nitrates in the fertiliser

Algae grow quickly

Algae become overcrowded and block light for photosynthesis. The pond weed will die

Bacteria feed on dead algae

As the number of bacteria grow, they use up all the oxygen in the oxygen in the water. Fish die.

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Spec Point: Animals are frequently treated with antibiotics and hormones to increase food yields and profitability (4.5)

Antibiotics are used in the animal farming industry as a prophylactic treatment to prevent animals getting diseases

Unfortunately, this practice led to bacteria becoming resistant to antibiotics. This introduces a risk to humans and other animals.

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Intensive Farming

Intensive Farming- many animals kept in close spaces, warm spaces to reduce energy loss

  • Given antibiotic treatment

  • Growth Hormones

  • Use of pesticides

  • Monoculture

  • Removing hedges

  • Use of fertilisers (artificial)

  • Herbicides

  • Insecticides

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Organic Farming

Organic Farming

  • No herbicides, insecticides, pesticides

  • Natural fertilizer

  • Space left free in the centre of fields (for nesting)

  • Keep Hedges and trees

  • Mixed crops

  • Pastures

  • Less meat

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Breeds are different varieties of the same species. Dogs have approximately 150 breeds but they are all the same species.

Breed= animals of the same species that vary in many characteristics (called varieties in plants). They Inherit these characteristics from their parents.

However selective breeding can sometimes backfire:

English Bulldogs

  • Short tailed often have backbone deformities

  • Short snouted often have breathing difficulties

  • Narrowed hips causes problems giving birth

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It can take decades, even centuries, to get the right characteristics in a breed/variety by selective breeding.

This is because

  1. The right characteristic may involve several genes being in the right combination

  2. Multiple alleles of one gene can be recessive and dominant. Recessive genes can be ‘hide’ when they are heterozygous. However, there is always a chance they can become homozygous in later generations giving an unwanted phenotype.

A much quicker way of getting desired characteristic is by using biotechnology

Genes can be inserted/modified using modern biotechnology techniques. Therefore the right characteristics can be developed within one generation. An organism that has undergone this treatment is called a genetically modified organism.

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GM Crops - Pro's


Manufacturers claim GM crops give higher yields and could help the developing world

Some GM Crops can be enriched with nutrients to help developing nations that  lack nutrients in their diets

Crops may be manipulated to grow in lower temperatures with less water and fertilisers meaning lower cost, and less impact to the environment

GM Crops may reduce pesticide use according to a US study

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GM Crops- Con's


Transplanted genes may get out in to the natural environment creating ‘superweeds’

Not everyone is convinced GM crops are safe for consumption. People are worried they may develop allergies to the food

Cross contamination of non-GM crops could destroy the GM-free trade

GM crops increase pesticide use as farmers spray freely

GM crops could affect farmland biodiversity if there are no weeds as a food source for wildlife

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GM Crops

GM plants could solve lots of problems

·         Crops can be produced cheaper if they are resistant to certain pests and weed killers

·         This would mean food would be cheaper and poorer families could eat better

The safety of GM foods is still under debate and this has implications for public acceptance and regulation

DNA from daffodils has been inserted into Rice

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Food Miles

 Spec Point: Food miles describes the impact that changing patterns of food production has had in the seasonal availability of food. There needs to be a balance between growing crops in the optimum climate and transportation to markets (4.2)

Food miles take in the environmental impact of transport distance but they do not take into account:

·         The environmental impact of production methods (e.g. growing food in conditions which are not optimum for them- strawberries in heated greenhouses)

·         The method of transportation (air freighting vs shipping)

·         Other environmental measurements such as overuse of pesticides, antibiotics etc.

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Life Cycle Assessment

A growing field of increasing importance is Life Cycle Assessment (LCA)

Life Cycle Assessment involves measurement and evaluation of a wide range of environmental impact parameters and use of this information to inform process and product improvements.

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Food Distribution

Spec point: Pressures on food distribution are increasing (4.1)

Pressures such as:

·         Transportation costs

·         Currency exchange

·         Impact on the environment (pollution, global warming)

·         Ethical implications (e.g. Fairtrade)

·         Food security

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