Farming Flashcards
How is soil structure controlled by farmers?
Ploughing fields to break up compact soil
How are soil minerals controlled by farmers?
Adding fertiliser or manure to soil
How is soil pH controlled by farmers?
Adding lime (calcium salts) to acidic soils Few soils are too alkaline to need treatment
How are CO2, heat and light controlled by farmers?
Cannot be controlled for field crops but in a greenhouse
Burning fuels in a greenhouse produces both carbon dioxide and heat
Artificial lighting
Reason for controlling soil minerals
Extra minerals increase growth rate
Reason for controlling soil structure
Good aeration & drainage allow better uptake of mineral ions & water
Reason for controlling soil pH
To neutralise the soil - an unsuitable pH can affect crop growth as it reduces uptake of mineral ions
Pests definition
Organisms that reduce the yield of crops or farm animals
Disadvantages of pest control 4
Expensive
Pest may become resistant
Environmental damage
Bioaccumulation
What is Bioaccumulation
Pesticides stored in fatty tissues of animals
Biomagnification
Pesticide concentration increases in animal tissues
What is biological control
Introducing a predator to reduce pest numbers
Why do farmers prefer to spray herbicides on seeds early in the growing season
To kill the weeds before they produce seeds reducing need to use more herbicide later in the season
Eutrophication
When a lake or river becomes enriched with nutrients (eg from fertilisers applied to fields, excess plant growth is followed by decay. Microorganisms use up oxygen from the water so that other organisms can no longer survive
Pheromones(animal sex hormones) as biological control
Animal sex hormones/pheromones used to attract either the males or females of a species, which are then destroyed, reducing the reproductive potential of the population
