5.4.3
Fertilisers & Eutrophication
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Fertilisers
Fertilisers replace nutrients lost from the soil during harvesting and removing livestock to help maximise yields in agriculture.

Agricultural impacts on soil
- Agriculture leads to depleted levels of nutrients in the soil (e.g. nitrogen and phosphates).
- This is because when crops are removed for harvest, they are not decomposed and the nutrients are not returned to the soil for reuse.
- Removing livestock for slaughter also decreases nutrient levels because they are not replaced by decomposition.

Using fertilisers
- Fertilisers can be used to replace the nutrients (e.g nitrogen and phosphate) lost through agriculture.
- Increasing nutrient levels by fertilisers allows farming to continue without negative impacts on the crop or livestock quality.
Types of Fertilisers
There are two types of fertiliser:

Artificial fertilisers
- Artificial fertilisers (e.g. ammonium nitrate) are inorganic.
- Artificial fertilisers are produced specifically for replacing nutrients.

Natural fertilisers
- Natural fertilisers (e.g. composted food waste, manure) are organic.
- Natural fertilisers are taken from organic matter and used to replace nutrients.
Eutrophication
Using fertilisers can have negative impacts on the environment. For example, eutrophication can happen when too much fertiliser is used. The process of eutrophication is:

1) Leaching and overflow
- Fertilisers that are sprayed onto fields can leach through the soil or flow into ponds, rivers and lakes.
- Leaching is when water-soluble plant nutrients are lost from the soil.
- This causes a build up of nutrients in the water.

2) Algal overgrowth
- The excess of nutrients cause algae to rapidly grow on the surface of the water.
- As algae accumulate, light is prevented from reaching the plants in the water beneath.

3) Plant death
- The plants underneath the algae eventually die because there is insufficient light for them to photosynthesise.

4) Increase in numbers of bacteria
- Bacteria decompose the dead plants.
- As numbers of bacteria increase, the oxygen concentration in the water decreases.
- Fish and other organisms will now die because there is not enough oxygen.
1Biological Molecules
1.1Monomers & Polymers
1.2Carbohydrates
1.3Lipids
1.4Proteins
1.4.1The Peptide Chain1.4.2Investigating Proteins1.4.3Primary & Secondary Protein Structure1.4.4Tertiary & Quaternary Protein Structure1.4.5Enzymes1.4.6Factors Affecting Enzyme Activity1.4.7Enzyme-Controlled Reactions1.4.8End of Topic Test - Lipids & Proteins1.4.9A-A* (AO3/4) - Enzymes1.4.10A-A* (AO3/4) - Proteins1.4.11Diagnostic Misconceptions - Enzyme Inhibitors
1.5Nucleic Acids
1.6ATP
1.7Water
1.8Inorganic Ions
2Cells
2.1Cell Structure
2.2Mitosis & Cancer
2.3Transport Across Cell Membrane
2.4Cell Recognition & the Immune System
2.4.1Immune System2.4.2Phagocytosis2.4.3T Lymphocytes2.4.4B Lymphocytes2.4.5Antibodies2.4.6Primary & Secondary Response2.4.7Vaccines2.4.8HIV2.4.9Ethical Issues2.4.10End of Topic Test - Immune System2.4.11Exam-Style Question - Immune System2.4.12A-A* (AO3/4) - Immune System2.4.13Diagnostic Misconceptions - Humoral vs Cellular
3Substance Exchange
3.1Surface Area to Volume Ratio
3.2Gas Exchange
3.3Digestion & Absorption
3.4Mass Transport
3.4.1Haemoglobin3.4.2Oxygen Transport3.4.3The Circulatory System3.4.4The Heart3.4.5Blood Vessels3.4.6Cardiovascular Disease3.4.7Heart Dissection3.4.8Xylem3.4.9Phloem3.4.10Investigating Plant Transport3.4.11End of Topic Test - Mass Transport3.4.12A-A* (AO3/4) - Mass Transport3.4.13Diagnostic Misconceptions - Concentration Gradient3.4.14Diagnostic Misconceptions - Cardiac Cycle3.4.15Diagnostic Misconceptions - Carrying Capacity3.4.16Diagnostic Misconceptions - Translocation
4Genetic Information & Variation
4.1DNA, Genes & Chromosomes
4.2DNA & Protein Synthesis
4.3Mutations & Meiosis
4.4Genetic Diversity & Adaptation
4.5Species & Taxonomy
4.6Biodiversity Within a Community
4.7Investigating Diversity
5Energy Transfers (A2 only)
5.1Photosynthesis
5.1.1Overview of Photosynthesis5.1.2Photoionisation of Chlorophyll5.1.3Production of ATP & Reduced NADP5.1.4Cyclic Photophosphorylation5.1.5Light-Independent Reaction5.1.6A-A* (AO3/4) - Photosynthesis Reactions5.1.7Limiting Factors5.1.8Photosynthesis Experiments5.1.9End of Topic Test - Photosynthesis5.1.10A-A* (AO3/4) - Photosynthesis
5.2Respiration
5.2.1Overview of Respiration5.2.2Anaerobic Respiration5.2.3A-A* (AO3/4) - Anaerobic Respiration5.2.4The Link Reaction5.2.5The Krebs Cycle5.2.6Oxidative Phosphorylation5.2.7Respiration Experiments5.2.8End of Topic Test - Respiration5.2.9A-A* (AO3/4) - Respiration5.2.10Diagnostic Misconceptions - Aerobic vs Anaerobic
5.3Energy & Ecosystems
6Responding to Change (A2 only)
6.1Nervous Communication
6.2Nervous Coordination
6.3Muscle Contraction
6.4Homeostasis
6.4.1Overview of Homeostasis6.4.2Blood Glucose Concentration6.4.3Controlling Blood Glucose Concentration6.4.4End of Topic Test - Blood Glucose6.4.5Primary & Secondary Messengers6.4.6Diabetes Mellitus6.4.7Measuring Glucose Concentration6.4.8Osmoregulation6.4.9Controlling Blood Water Potential6.4.10ADH6.4.11End of Topic Test - Diabetes & Osmoregulation6.4.12A-A* (AO3/4) - Homeostasis6.4.13Diagnostic Misconceptions - Effect of ADH
7Genetics & Ecosystems (A2 only)
7.1Genetics
7.2Populations
7.3Evolution
7.3.1Variation7.3.2Natural Selection & Evolution7.3.3End of Topic Test - Populations & Evolution7.3.4Types of Selection7.3.5Types of Selection Summary7.3.6Overview of Speciation7.3.7Causes of Speciation7.3.8Diversity7.3.9End of Topic Test - Selection & Speciation7.3.10A-A* (AO3/4) - Populations & Evolution7.3.11Diagnostic Misconceptions - Types of Speciation
8The Control of Gene Expression (A2 only)
8.1Mutation
8.2Gene Expression
8.2.1Stem Cells8.2.2Stem Cells in Disease8.2.3End of Topic Test - Mutation & Gene Epression8.2.4A-A* (AO3/4) - Mutation & Stem Cells8.2.5Regulating Transcription8.2.6Epigenetics8.2.7Epigenetics & Disease8.2.8Regulating Translation8.2.9Experimental Data8.2.10End of Topic Test - Transcription & Translation8.2.11Tumours8.2.12Correlations & Causes8.2.13Prevention & Treatment8.2.14End of Topic Test - Cancer8.2.15A-A* (AO3/4) - Gene Expression & Cancer
8.3Genome Projects
Jump to other topics
1Biological Molecules
1.1Monomers & Polymers
1.2Carbohydrates
1.3Lipids
1.4Proteins
1.4.1The Peptide Chain1.4.2Investigating Proteins1.4.3Primary & Secondary Protein Structure1.4.4Tertiary & Quaternary Protein Structure1.4.5Enzymes1.4.6Factors Affecting Enzyme Activity1.4.7Enzyme-Controlled Reactions1.4.8End of Topic Test - Lipids & Proteins1.4.9A-A* (AO3/4) - Enzymes1.4.10A-A* (AO3/4) - Proteins1.4.11Diagnostic Misconceptions - Enzyme Inhibitors
1.5Nucleic Acids
1.6ATP
1.7Water
1.8Inorganic Ions
2Cells
2.1Cell Structure
2.2Mitosis & Cancer
2.3Transport Across Cell Membrane
2.4Cell Recognition & the Immune System
2.4.1Immune System2.4.2Phagocytosis2.4.3T Lymphocytes2.4.4B Lymphocytes2.4.5Antibodies2.4.6Primary & Secondary Response2.4.7Vaccines2.4.8HIV2.4.9Ethical Issues2.4.10End of Topic Test - Immune System2.4.11Exam-Style Question - Immune System2.4.12A-A* (AO3/4) - Immune System2.4.13Diagnostic Misconceptions - Humoral vs Cellular
3Substance Exchange
3.1Surface Area to Volume Ratio
3.2Gas Exchange
3.3Digestion & Absorption
3.4Mass Transport
3.4.1Haemoglobin3.4.2Oxygen Transport3.4.3The Circulatory System3.4.4The Heart3.4.5Blood Vessels3.4.6Cardiovascular Disease3.4.7Heart Dissection3.4.8Xylem3.4.9Phloem3.4.10Investigating Plant Transport3.4.11End of Topic Test - Mass Transport3.4.12A-A* (AO3/4) - Mass Transport3.4.13Diagnostic Misconceptions - Concentration Gradient3.4.14Diagnostic Misconceptions - Cardiac Cycle3.4.15Diagnostic Misconceptions - Carrying Capacity3.4.16Diagnostic Misconceptions - Translocation
4Genetic Information & Variation
4.1DNA, Genes & Chromosomes
4.2DNA & Protein Synthesis
4.3Mutations & Meiosis
4.4Genetic Diversity & Adaptation
4.5Species & Taxonomy
4.6Biodiversity Within a Community
4.7Investigating Diversity
5Energy Transfers (A2 only)
5.1Photosynthesis
5.1.1Overview of Photosynthesis5.1.2Photoionisation of Chlorophyll5.1.3Production of ATP & Reduced NADP5.1.4Cyclic Photophosphorylation5.1.5Light-Independent Reaction5.1.6A-A* (AO3/4) - Photosynthesis Reactions5.1.7Limiting Factors5.1.8Photosynthesis Experiments5.1.9End of Topic Test - Photosynthesis5.1.10A-A* (AO3/4) - Photosynthesis
5.2Respiration
5.2.1Overview of Respiration5.2.2Anaerobic Respiration5.2.3A-A* (AO3/4) - Anaerobic Respiration5.2.4The Link Reaction5.2.5The Krebs Cycle5.2.6Oxidative Phosphorylation5.2.7Respiration Experiments5.2.8End of Topic Test - Respiration5.2.9A-A* (AO3/4) - Respiration5.2.10Diagnostic Misconceptions - Aerobic vs Anaerobic
5.3Energy & Ecosystems
6Responding to Change (A2 only)
6.1Nervous Communication
6.2Nervous Coordination
6.3Muscle Contraction
6.4Homeostasis
6.4.1Overview of Homeostasis6.4.2Blood Glucose Concentration6.4.3Controlling Blood Glucose Concentration6.4.4End of Topic Test - Blood Glucose6.4.5Primary & Secondary Messengers6.4.6Diabetes Mellitus6.4.7Measuring Glucose Concentration6.4.8Osmoregulation6.4.9Controlling Blood Water Potential6.4.10ADH6.4.11End of Topic Test - Diabetes & Osmoregulation6.4.12A-A* (AO3/4) - Homeostasis6.4.13Diagnostic Misconceptions - Effect of ADH
7Genetics & Ecosystems (A2 only)
7.1Genetics
7.2Populations
7.3Evolution
7.3.1Variation7.3.2Natural Selection & Evolution7.3.3End of Topic Test - Populations & Evolution7.3.4Types of Selection7.3.5Types of Selection Summary7.3.6Overview of Speciation7.3.7Causes of Speciation7.3.8Diversity7.3.9End of Topic Test - Selection & Speciation7.3.10A-A* (AO3/4) - Populations & Evolution7.3.11Diagnostic Misconceptions - Types of Speciation
8The Control of Gene Expression (A2 only)
8.1Mutation
8.2Gene Expression
8.2.1Stem Cells8.2.2Stem Cells in Disease8.2.3End of Topic Test - Mutation & Gene Epression8.2.4A-A* (AO3/4) - Mutation & Stem Cells8.2.5Regulating Transcription8.2.6Epigenetics8.2.7Epigenetics & Disease8.2.8Regulating Translation8.2.9Experimental Data8.2.10End of Topic Test - Transcription & Translation8.2.11Tumours8.2.12Correlations & Causes8.2.13Prevention & Treatment8.2.14End of Topic Test - Cancer8.2.15A-A* (AO3/4) - Gene Expression & Cancer
8.3Genome Projects
Practice questions on Fertilisers & Eutrophication
Can you answer these? Test yourself with free interactive practice on Seneca — used by over 10 million students.
- 1
- 2Which of these is NOT a use of fertilisers?Multiple choice
- 3What are the two types of fertiliser?Fill in the list
- 4
- 5Which of these is NOT a feature of natural fertilisers?Multiple choice
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