Climate zones Flashcards
What are base temperatures?
Below the base temperature plants can’t grow so it determines the earliest sowing date (wheat=0 degrees and maize=10 degrees)
What effects crop growth?
- Temperature (optimum and maximum)
- Precipitation (quantity and timing)
- Day length
- Life cycle length
What is the equation for photosynthesis?
6CO2 + 6H20 = C6H12O6 + 6O2 or carbon dioxide + water = glucose + oxygen
What are the three types of photosynthesis?
C3, C4 and CAM
Process of C3 photosynthesis
- Carbon dioxide enters
- Gases are exchanged through open stomata
- Gas goes through Calvin cycle to produce sugar
Process of C4 photosynthesis
- Carbon dioxide enters
- Gases are exchanged through slightly open stomata
- Carbon uptake by PEP carboxylase requires ATP
- Gas goes through Calvin cycle to produce sugar
Process of CAM photosynthesis
- Carbon dioxide enters
- Gases exchanged at night through open stomata
- Carbon uptake by PEP carboxylase requires ATP
- Gas goes through Calvin cycle during the day as stomata closes
- Produces energy
Advantages and disadvantages of C3 photosynthesis
Advantages: efficient use of ATP
Disadvantages: photorespiration
Examples: most plants
Advantages and disadvantages of C4 photosynthesis
Advantages: water conservation
Disadvantages: energy requirement
Examples: sugarcane, maize and grass
Advantages and disadvantages of CAM photosynthesis
Advantages: water conservation
Disadvantages: energy requirement and slow growth
Examples: pineapple, cacti, succulents
Why is most maize grown in the UK used as fodder?
Because maize has minimum temperature of 10 degrees and so has to be harvested earlier
Why are C4 crops grown in Africa and South America?
Because they have a higher max temperature
How much does agriculture contribute to total greenhouse gasses?
Agriculture contributes to 13% and the whole food system contributes to 35%
How do plants adapt to increasing temperatures?
- Stalks become longer
- Leaves shrink to save water
- Grow away from other plants to avoid weakness
For each 1 degrees increase in temperature how much does yield change in crops?
- Maize: 6% decrease
- Rice: 3.2% decrease
- Wheat: 7.4 % decrease
Percentages increase for night time temperature increase
How does climate change effect crop growth?
Extreme weather events increase causing land use change, overgrazing, continuous cropping and soil erosion
How can crops be protected from climate change?
- Pest and disease control
- Crop choice
- Improved germplasm
- Breeding for genetic variation
How do livestock cope in weather changes?
Cold environments: thicker coats, smaller ears
Warm environments: thin coats, humps to store fat and water
Temperature zones
Grass based systems for cattle and sheep and free-range movement for pigs and poultry
Arid zones
Pastoral systems (moving animals around for food and water) and nomadic lifestyle
Equatorial zone
- Variation in size of producers
- Increase use of hybrid genetics
- Consistent warm temperature
What are the thermoneutral zones for animals?
- Cattle (dairy): 5-25°C
- Cattle (beef): 0-25°C
- Sheep: 21-31°C
- Goat: 10-20°C
- Poultry: 15-23°C
- Pigs: 10-21°C
Why is heat stress bad for cattle?
Worse milk yield
How can heat stress be avoided?
More energy dense diet to increase body weight and milk yield and providing cattle with shade to lower body temperature
How can livestock contribute less to climate change?
- Mixed crop-livestock system can be used to use less land
- A sustainable diet with plant protein
- Efficient systems to prevent long emissions of greenhouse gases
