Artificial Control Of The Environment Flashcards by Caitlin Dickinson

What is a limiting factor in agriculture

Any condition or resource that restricts the growth and productivity of crops or livestock

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Biotic factors that may affect food production

Disease
Pests
Pollinators
Weeds

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Abiotic factors that may affect food production

Temperature
Soil pH
Water availability
Light availability humidity
Nutrient availability

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Why would you want to manipulate temperature

Promote photosynthesis
Increase length of growing season
Avoid frost
Control evaporation rates

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Examples of how temperature can be manipulated

Greenhouses
Polytunnels
Ventilation

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Why would you want to manipulate light

Photosynthesis
Trigger animal breeding/day length
Longer day length - increased milk production

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Examples of how light can be manipulated

Removing or adding lights

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Why would you want to manipulate carbon dioxide

Photosynthesis

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Examples of how carbon dioxide can be manipulated artificially

Buy CO2 canisters - pump into enclosed spaces
Burn fossil fuels

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Why is water important for plants

Photosynthesis
Nutrients go into solution - taken up by plants
Turgidity in plants

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Why is too little water a problem

Lack of gas exchange
Lack of nutrient uptake
Lack of photosynthesis

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What can be done to improve to little water

Irrigation methods
Mulching
Drought resistant crops
Terracing
Tide ridging

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Why is too much water a problem

Roots become waterlogged
Lack of gas exchange
Soil biota - anaerobic
Soil erosion

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What can be done to improve too much water

Drip irrigation
Improved drainage systems
Cover crops
Addition of sand - increases drainage

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Why would you want to manipulate wind velocity and what are the benefits

Prevent soil erosion
Reduce crop damage
Increase rate of evaporation - reduce water losses

Benefits:
Seed dispersal
Dispersal of disease
Dispersal of pollen

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Examples of how wind velocity can be reduced

Windows
Rows of trees
Cover crops
Windbreakers
Multicropping

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What do we mean by nutrients

A substance that provides nourishment
Different nutrients are required for different biological processes

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What are macronutrients

Nutrients that are needed in larger amounts
E.g. nitrogen

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Function of nitrogen in the plant

Protein synthesis
Nitrogen cycle

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Form that plants absorb nitrogen

Ammonium ions
Nitrates, nitrites

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Function of phosphorus in the plant

Used in ATP for photosynthesis
Cell division
Energy transfer

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Form that plants absorb phosphorus

Dehydrogen phosphate

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Function of potassium in the plant

Movement of water and nutrients
Enzyme activation

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Form that plants absorb potassium

K+

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What are micronutrients

Nutrients required in small amounts

Description of a natural fertiliser

Breakdown of organic material which releases nutrients

Examples of natural fertilisers

Manure Sewage sludge

Advantages of natural fertilisers

Nutrient rich Reduce chemical runoff Increase soil biota

Disadvantages of natural fertilisers

Slower release Odour issues Pest attraction

Description of artificial fertilisers

Haber process Anthropogenic

Examples of artificial fertilisers

NPK

Advantages of artificial fertilisers

High nutrient concentration Consistent Easy to apply - control release

Disadvantages of artificial fertilisers

Soil degradation Water pollution - eutrophication Dependency

Description of nitrogen fixation

Converts atmospheric nitrogen into nitrates, nitrites Planting legumes - encourage nitrogen fixing bacteria

Description of crop rotation

Continuous movement of crops within different fields in different years Leaving one field fallow

Why would you want to manipulate pH

Effects contents of heavy metas Range of tolerance for plants

Problem with low pH and hat to do to correct it

Dissolving of heavy metals Plant tissue break down Adding crushed limestone

Problem with high pH and what to do to correct it

Essential nutrients wont go into soil - can’t enter the tissue Adding sulphur

How can pests damage crops and livestock

Disease vector Consume valuable crops Cause stress to livestock Increase competition for space etc

What types of agricultural practices are particularly susceptible to attack from pests

Monocultures High density cropping

Major pest groups and examples

Insects - Aphids Molluscs - Garden snail Birds - Pigeons

Definition of Endemic and an example

Native organisms that consistently exist in a specific area Example: Fox

Definition of Epidemic and an example

Pests that suddenly increase in population, causing widespread damage Example: Locusts plague

Definition of Indigenous and an example

Native species that have evolved in a specific region Example: Native grasshopper

Definition of Introduced and an example

Non-native species that have been brought into a new environment, either intentionally or accidentally Example: New Zealand flat worm

How can we control pests

Parasitic wasp - biological control Crop rotation - cultural control Hand-picking - mechanical control

Explanation and benefits of weeding

Removal of weeds + Reduce competition Improve soil health

Explanation and benefits of mulching

Add DOM to the soil So weeds can’t get there + Increase nutrients Improve aesthetic value

Explanation and benefits of crop rotation

Movement of crops to different fields in different years + Constant cycle of nutrients Reduce soil erosion

Explanation and benefits of barrier controls

Plant deterrent crop + Provides protection to crops

Explanation and benefits of culling

Killing of species + Maintain population sizes Disease control

Explanation and benefits of biological control

Using a species to kill pests + Maintain population of pests Enhances biodiversity

Explanation and benefits of predator habitats

Encourage biological controllers + Increase biodiversity Improve soil health

Explanation and benefits of intergrated control

Combining many methods + Cost-effective Increased biodiversity

Explanation and benefits of polyculture/companion crops

Lots of crops in one area Prevents one crop becoming dominant + Increase biodiversity Improve soil health Increase yield

What are the newer methods of pest control without pesticides

Pheromone trap Animal hormones Disease introduction Sterile-male techniques

Explanation and benefits of pheromone traps

Hormone given off to attract a mate Gather pheromone in a trap to attract pests + decrease damage to agriculture

Explanation and benefits of animal hormones

Trigger significant part of the life-cycle Trigger something to happen too soon - organism cannot survive + Targeted control Decrease chemical use

Explanation and benefits of disease introduction

Introduce disease that’s specific to the pest + improve crop health

Explanation and benefits of sterile-male techniques

Expose males to ionizing radiation Female insects can mate once but don’t produce any young

Properties of chemical pesticides

Toxicity Specificity Persistent Solubility

Explain the difference between contact and systemic chemical pesticides

Contact - sprayed on organism, sits on the outer layer - toxic to the organisms that consumes the sprayed organism Systemic - applied to the soil, taken up by the tissue of the plants

How can pesticides be applied

Solid - goes into solution when it rains Liquid - sprayed - systemic or contact Gas - bug bomb, slug pellets