OCR Salters B Chemistry Agriculture and Industry Storylines 1 and 2

  • Created by: Emily
  • Created on: 22-01-13 21:47
What can growing one crop again and again on the same soil do to the soil?
It can destroy its fertility by depleting specific nutrients
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What are sustainable systems of agriculture?
Agriculture that can go on indefinitely without degrading the environment
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Name the three elements plants use in relatively large amounts (also name where these elements come from)
Carbon, hydrogen and oxygen mostly from carbon dioxide and water
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Name a few elements plants use in relatively small amounts that come from the soil
Nitrogen, potassium, calcium, magnesium, iron, zinc
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Why might people buy organic food?
Eating organic food is one way to reduce consumption of pesticide and herbicide residues. Consumers may also believe the foods to be safer and more nutritious than conventionally farmed foods
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What is organic chemistry?
The study of the compounds of carbon with the exception of carbon dioxide and carbon monoxide and carbonated
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What is organic farming?
Farming process using fertilisers and pesticides of only plant or animal origin. There is restricted use of artificual fertilisers and pesticides, and emphasis on soil health (by crop rotation and manure and compost application)
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What is soil?
Mixture of weathered rock fragments and organic matter making a porous substance that can hold air and water
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How are soil minerals produced?
By weathering the rocks making up the Earth's crust
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How are essential ions held in soil?
Clay minerals can bind positive ions to their surfaces
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What is the organic material of soil made up of?
Plant debris, animal remains and excreta (products formed by decomposition of all things)
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What is mineralisation?
When elements in organic compounds are converted into inorganic ions
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What is humus?
A complex organic substance which a component of soil, resulting from the breakdown of plant material in a process called humification
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Name some major components of humus in soil
Carboxylic acids (and their derivatives of benzene) and phenolic compounds
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How does the humus in soil hold a variety of nutrient ions?
The COOH and phenol group are common in humus, both of which can lose an H+ ion to leave negatively charged groups in humus which can form ionic bonds with metal cations
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The nutrients of the organic store (partly in the soil and partly on top) are replenished by...
Organic manure, animal excretions and by death and decay of living organisms
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Weathering of soil and rock minerals releases more/less ions in the inorganic store in soil
More
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How can nutrients and nitrogen be lost from the inorganic and organic stores in the soil?
Nutrients can be lost by being leached out of the top layers of soil by rainwater and nitrogen can be lost by conversion into gases e.g. NH3, N2 and N2O which disperse into the atmosphere
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How many square metres are in 1 hectare?
1 x 10^4 square metres
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What is almost all the nitrogen in soil not readily available to plants?
It is present in complex organic compounds
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In order for food produce to be sold under the Soil Association, what standards must be met?
Sewage sludge, effluents or sludge-based composts not to be used. Residues or manure from livestock systems that don not meet their standards must not be used. Chemically synthesised fertilisers must not be used
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Name at least 2 methods farmers use to maintain fertility and nitrogen content of soil
Growing crops that add nutrients to the soil as part of crop rotation, applying composts and farmyard manures, applying certain permitted mineral fertilisers and supplementary nutrients
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Describe how applying certain permitted mineral fertlisers and supplementary nutrients maintains the fertility of soil
Certain minerals (e.g. sulfur) and trace elements (e.g. boron, copper) can be applied to soil which replace depleted nutrients and keep the soil fertile
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Applying manure to soil increases the ________ (element) content. It has also increased the population of what organisms?
Nitrogen. Soil microorganisms and small animals e.g. earthworms which convert organic nitrogen into forms usable by plants
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Other cards in this set

Card 2

Front

What are sustainable systems of agriculture?

Back

Agriculture that can go on indefinitely without degrading the environment

Card 3

Front

Name the three elements plants use in relatively large amounts (also name where these elements come from)

Back

Preview of the front of card 3

Card 4

Front

Name a few elements plants use in relatively small amounts that come from the soil

Back

Preview of the front of card 4

Card 5

Front

Why might people buy organic food?

Back

Preview of the front of card 5
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