5a Flashcards
How can greenhouses increase the yield of crops?
Can provide artificial lighting, warmth and CO2. They are limiting factors for photosynthesis. More photosynthesis —> More yield.
Effects of increased carbon dioxide and increased temperature on crop yield
Crop yield is increased. They all limit the rate of photosynthesis and therefore growth.
How can fertilizer increase crop yield
Fertilizers provide mineral ions to the soil. Plants (crops) need these mineral ions for growth. Fertilizers can therefore increase yield.
Why are pesticides used
Pesticides eliminate pests that reduce the yield of a crop.
Fertiliser Contents
NPK
Types of pesticides
Herbicides
Insecticide
Fungicide
Moluscide
Pesticide Problems
- Persistent
- Resistance develops
- Bioaccumulation
- Toxic (kills bees)
Fish Farming
Fish are farmed because they are a source of high-quality protein. They are farmed in densely stocked enclosures in rivers, lakes, or the sea.
Advantages:
- Water quality can be monitored
- The diet of the fish can be carefully controlled
- Selective breeding programs can increase the quality of the fish
- Fish are protected from predators
Role of lactobacilus
- Used in yogurt production
- Breaks down lactose into lactic acid
Role of yeast
- Bread and beer production
- Respire anaerobically to release ethanol and carbon dioxide
- Carbon dioxide to make bread rise. Ethanol to give alcoholic content.
Fermentor
- Used to give suitable conditions for the growth of microorganisms
- Control: temperature, nutrition, pH, sterelisation, oxygentaion…