Class Level 6th Year Agricultural Science
Duration: 15 minutes
Environmental impact of agriculture
Class Level 6th Year Agricultural Science
Duration: 15 minutes
Environmental impact of agriculture
Learning Intentions and Success Criteria
Learning Intentions
We are learning to:
Identify the main environmental impacts of agriculture in Ireland
Explain how farming contributes to greenhouse gas emissions
Describe ways farmers can reduce negative environmental impacts
Success Criteria
By the end of the lesson, you should be able to:
Name three greenhouse gases produced by agriculture
Give one example of how farming affects water quality or biodiversity
Describe one measure farmers use to reduce environmental impact
Let Discuss
“Agriculture produces about one-third of Ireland’s greenhouse gas emissions. Should farmers be blamed for climate change?”
Do You agree or disagree with this statement and why ?
“Let’s look at how agriculture impacts the environment — and what farmers are doing about it.”
Greenhouse gas emissions
Agriculture accounts for 32% of our overall greenhouse gas emissions.
The three main greenhouse gases produced by farming are: carbon dioxide, methane and nitrous oxide.
Activating Prior Knowledge
Quick Think–Pair–Share:
“What farming activities might affect the environment?”
Expected answers:
Fertilisers
Cattle / livestock
Slurry
Drainage
Greenhouse gas emissions
Carbon dioxide is produced by the combustion of fossil fuels,
methane is produced by ruminating animals
main source of nitrous oxide is artificial fertilisers and animal manures.
Other than cows name another ruminant farm animal.
Answer- sheep or goats
Excess fertilizer leads to pollution
nitrous oxide formation.
Fertilizers can be ammonium- or nitrate-based.
When plant roots don't take up all the nutrients, they undergo a series of microbe-mediated transformations.
nitrogen re-enters the atmosphere as nitrogen gas (N2) and — in smaller part — as N2O, a potent greenhouse gas.
Volatilisation
“Why do ruminating animals produce methane but pigs and poultry don’t?”
Answer - They have a special stomach chamber called the rumen, which works like a giant fermentation vat. Pigs and poultry have simple stomachs
Best Day to Spread Slurry ?
A wet day
A Warm/hot day
A mild day
Answer - A mild day is best to spread slurry because nutrient losses are lower and the soil can absorb the slurry better, reducing pollution and improving fertiliser value
Water quality
Eutrophication
(from the addition of nitrates and phosphates), sedimentation and the addition of pathogens are the main risks to water quality from agriculture.
“What happens to aquatic life when too many nutrients enter a river?”
Biodiversity
Changes in agricultural practices over the last century have led to a loss of biodiversity.
Definition : Biodiversity is the variety of plants and animals living in a habitat.
Biodiversity
The agricultural activities that cause a decrease in biodiversity are:
Land drainage
Land drainage has led to a reduction in peatlands, and wetlands, important habitat for birds such as
the curlew, whooper swan, lapwing and snipe.
Climate change
Climate change is likely to cause changes in the life cycles of plants, insects, birds and mammals.
Climate change is likely to bring new pests and diseases to this country, e.g.
blue tongue virus.
“Why might climate change lead to new pests and diseases in Ireland?”
Answer -In short, a warmer and wetter climate makes Ireland more welcoming to pests and diseases that were once kept away by colder conditions.
Unstable grazing regimes
The use of more productive grass species (perennial ryegrass) has led to a reduction in pollinators such as bees, butterflies and hoverflies.
A change from natural grassland (wide variety of grass species and wildflowers)
The federation of Irish Beekeepers has reported that 30% of Irelands 101 bee species are on the verge of extinction.
Measures employed by the farming community to lessen its environmental impact
Exit Ticket
Students answer on paper
Exit Ticket:
Name one greenhouse gas produced by agriculture
State one way agriculture affects the environment
Give one measure farmers use to reduce impact