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9 Cards in this Set
- Front
- Back
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What is ammonification?
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Where saprobiotic microorganisms feed on organic ammonium containing compounds to release ammonium ions into the soil.
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What is nitrification?
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Free living nitrifying bacteria, oxidise the ammonium ions to form nitrate ions. It occurs in two steps: first the oxidation of ammonium ions to nitrite ions, and then the oxidation of nitrite ions to nitrate ions. The bacteria obtain their energy from this chemical reaction
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Why does soil need to have lots of air pockets, to raise productivity?
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Because the nitrifying bacteria require oxygen for nitrification
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What is nitrogen fixation?
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The process by which nitrogen gas is converted into nitrogen containing compounds.
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Which two types of bacteria can carry out nitrogen fixation?
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Free living nitrogen fixing bacteria, reduce nitrogen gas to ammonia, which they use to make amino acids. These compounds are released when they die. Mutualistic nitrogen fixing bacteria, exchange amino acids for carbohydrates on the roots of some plants
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Why does denitrification occur?
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When soils become waterlogged there is no air available, so there is an increase in the activity of anaerobic denitrifying bacteria, which convert soil nitrates into gaseous nitrogen
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What do organisms require nitrogen for?
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To manufacture proteins, nucleic acids and other compounds
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How do plants obtain their nitrogen?
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Absorb nitrate ions from the soil by active transport
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Name one of the most important sources of nitrates in the soil
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Decomposition of plants and animals
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