Unit 3.5 Food Production Flashcards
Crop yield
The quantity of crop grown and harvested.
Mechanisation
Using machinery in farming. Increases crop yield.
Monoculture
Growing the same crop over a large area.
More efficient, but reduces biodiversity.
Fertilisers
Used to replace essential nutrients (such as nitrates) removed in harvesting.
Inorganic (chemical) fertilisers
Highly soluble chemical fertilisers containing N,P and K.
Organic (natural) fertilisers
Manure and other waste materials which decompose in the soil to release nitrates.
Nitrates
The form in which nitrogen is absorbed by plants from the soil.
Used to build amino acids which are turned into plant protein.
Decomposers
Bacteria and fungi.
Feed on waste material and break it down, releasing ammonia into the soil.
Soil (nitrifying) bacteria
Convert ammonia into nitrite and then into nitrate, which can be absorbed by plant roots.
Eutrophication
Fertilisers are washed into rivers, causing algal blooms which block light and kill water plants.
The plants and algae die, and decomposers (bacteria) feed on them and reproduce, using up the dissolved oxygen in the water.
This kills fish and reduces biodiversity.
Herbicides
Weed killers.
Remove unwanted plants which compete with crop plants for light, water and nutrients and reduce yield.
They reduce biodiversity.
Pesticides
Kill the pests that attack crop plants.
Pests destroy leaves, affecting photosynthesis and production of sugars, so the plants don’t grow as well.
Pesticides increase crop yield, but reduce biodiversity.
Bioaccumulation
The build up of pesticides in the bodies of organisms over time.
Pesticides are passed along food chains, reaching toxic levels in top predators.
Biological control
Control of pests using a natural predator eg. using ladybirds to kill aphids (greenfly)
GM crops
Genetically modified crops.
Contain a gene from another organism, which allows them to produce a new protein, improving their characteristics. eg. Bt toxin in tomatoes, which kills insects that eat them.
