Chapter 11 Flashcards
What 3 factors affect agriculture?
Temperature
Water
Light
What are the importance of suitable temperatures?
Length of thermal growing season Frost-free period Impact on evaporation Biochemical reactions Thermoregulation
What field locations can affect temperature?
Low lying areas South-facing slopes Frosts in orchards Transparent woven plastic Livestock can be kept warm by shelters
Why is light important?
Photosynthesis
Longer days increase milk production
Poultry grow best with short days but more eggs are produced with long days
Some livestock mate when the days are shorter
How can light be controlled?
Artificial light
Why is water important?
Physical functions Nutrient absorption Used to transport materials Needed to replace lost water Gaseous exchange
3 ways water supply can affect crops?
Amount
Reliability
Quality
Whare are 2 problems caused by waterlogged soils?
Higher risk of fungal disease
Anaerobic soils
What methods are used to reduce water soil levels?
Excavation of drainage ditches Drainage pipes Deep ploughing Avoidance of soil compaction Provision and conditions to encourage worms
What methods are used to increase water availability?
Irrigation
Soil mulching
Suitable conditions for worms
Adding soil organic matter
How are soil nutrients made available in the soil?
Legumes
Soil bacteria
Crop rotation
What do organic fertilisers include?
Faecal materials
Animal food production
Plant food wastes
What are the 2 nutrient application methods?
Cultural methods
Mechanical application
What is hydroponics?
Growing of plants in a nutrient solution
What are the advantages of hydroponic production?
No soil so more appealing Pathogens can't live in the soil Increased growth rate Nutrients are available so are not limiting No weeds
What are the disadvantages of hydroponic production?
Involves high input of nutrients
Involves high skill level
How can aeration be controlled?
Ploughing
Low tillage methods
Addition of organic matter
Removing livestock from wet fields
How can soil pH be increased and reduced?
Increased - adding crushed lime
Decreased - spreading sulphur powder
What are the 4 topography factors?
Aspect
Frost pockets
Runoff rate
Use of machinery
What is the relief and how does it impact crops and livestock?
Altitudes
Crops - increased evaporation
Livestock - some species are adapted to high altitudes
What problems can wind velocity cause?
Increased soil erosion
Increased evaporation
Crop damage
How can pests affect agriculture?
Predators Compete for resources Pathogens Carry pathogens Reduce marketability
What is crop rotation?
Rotating crops so pests have to cultivate a different area each year
What are companion crops?
Crops that are grown together to increase productivity
What are the different ways of growing companion crops?
Nutrient supply
Barrier crops
Pest attraction
Support of pollinators
What are 2 types of pest control?
Sterile Male
Pheromone traps
What are sterile male techniques?
Sterilising the male so species can reproduce
What is a pheromone trap?
Release artificial scent to show pests are present or to kill off a gender of that particular pest
What are the properties of chemical pesticides?
Toxicity Specificity Persistence Solubility in water/lipids Contact action Systemic actions
What are the principles of integrated control?
Use of cultural techniques which makes the growth of the environment less suitable for pests
Use of cultural techniques that prevents build-up of pests
Cultivating species and varieties
Use of appropriate non-pesticide techniques
Use of pesticides when essential
How can pollinators services be aided?
Provision of food supply
Restricting the use of pesticides that harm pollinators
Introduction of bee hives
What do detritivores and decomposers do?
Increase nutrient availability through the breakdown of organic matter
How can population be controlled?
Optimum livestock/crop density
Monocultures
What are the advantages and disadvantages of asexual reproduction in plants?
Same characteristics so are predictable
No genetic variation for can’t be improved
What are the advantages of cloning animals?
Valuable animals that die can be replaced
Herds that are culled during disease can be replaced
Large numbers of individuals with desirable characteristics can be produced
What are two improved breeding techniques?
Artificial insemination
Embryo transfer
What is GM?
Genetic modification - addition of one characteristic into an organism
What is an example of genetic engineering?
The gene for omega 3 has been transferred into rapeseed oil to ensure that people get enough omega 3
What are the 2 advantages of GM?
Individual desirable characteristics can be introduced
Genes that wouldn’t normally be introduced can be
What are the 6 disadvantages of GM?
Can increase food allergies
Migration of genes from GM crops to conventional plants
Transfer through the food chain
Genes provide resistance to antibiotics
Increased costs to farmers
COncerns in LEDCs that GM crops will reduce the local indigenous crop diversity
What is intensive agriculture?
Optimising yields by concentrating inputs over a small area
What is extensive farming?
Optimising yields by spreading the inputs over a large area
What are energy subsidies?
In an agricultural system is any input that aids productivity but requires the use of energy
What are some examples of energy subsidies?
Manufacture of nitrate fertilisers Manufacture of pesticides Irrigation of water Fuel for machinery Manufacture of machinery Heat for drying grains Processing of food for consumers Transport of food
What are energy ratios?
A measure of efficiency by comparing energy inputs and then expressing them as a number of units of food energy produced.
What are food conversion ratios?
A measure of the mass of food needed to produce a given mass of livestock.
What is control of food chain energy losses?
An understanding of energy flow in food chains can help in developing more efficient ways of using farmland.
What are the habitat impacts of agriculture?
Drainage
Nutrient enrichment
Reduced biodiversity
What are the introduced species impacts on agriculture?
Introduced pests
Biological control species
What are the pollution impacts on agriculture?
Pesticides Nutrient pollution Nitrate toxicity Climate change Embodied energy
What changes are there in the hydrological cycle?
Irrigation water depends on the source
Soil erosion caused by agriculture can reduce the effects of soil
Soil compaction can increase runoff rates
Agriculture changes evapotranspiration rates
What are the social factors that affect agriculture?
Cultural factors Religious factors Ethical issues - Local food/food miles - Seasonal food - Free-range livestock - Organic food - Fairtrade food
What technology is available?
Machinery and equipment for processed Pesticides Fertilisers Genetic improvements Support infrastructure
What are the economic and political influences on agriculture?
Food aid
Grants
Guaranteed market
Food surpluses
How can food supplies be reduced?
Quotas Farm diversification Alternative crops and livestock Set-aside Agri-environmental schemes
What strategies are used to increase sustainable agriculture?
Cultural pest control Increased use of natural processes to supply nutrients Reduced use of artificial fertilisers Conservation of habitats Cultivation of low water use crops Low tillage farming Cultivation of rice varieties Retain natural and semi-natural ecosystems
