Farming and Fertilisers Flashcards
(14 cards)
How does farming impact natural cycles?
reduces nutrients in soils, as it prevents them from being returned in decomposition by saprobionts
Why are fertilisers needed?
- (intensive) farming practices reduce the nutrients in soil
- fertilisers provide a source of nutrients for crop growth
What are artificial fertilisers made from?
inorganic matter/materials, usually containing nitrogen, phosphorus and potassium
What are 4 examples of natural fertilisers?
- manure
- compost
- crops left over from harvest
- sewage sludge
What feature of artificial fertilisers make them more environmentally damaging?
very soluble
What are 2 environmental impacts of artificial, nitrogen-containing fertilisers?
- eutrophication
- plant death (from high concentrations)
- leaching: leads to water pollution
- reduced species diversity: as conditions favour grasses, nettle etc.
How does excessive fertiliser cause plant death?
water moves out of the plant to an area with a lower WP by osmosis
Explain the process of eutrophication and why it is harmful
- fertilisers added
- fertilisers leach into water sources
- causes rapid growth of algae, preventing light from reaching plants below
- plants below cant photosynthesise (die)
- saprobionts decompose dead plants (aerobic)
- lower [O2], so organisms/fish die
What is leaching?
water dissolves chemicals and causes them to run off into water sources from soil (ponds, rivers, lakes etc)
How does cattle impact natural cycles?
- eat crops, so no nutrients can be replenished
Give 2 reasons why farming cattle is less efficient than farming crops
- energy lost between trophic levels
- energy lost in respiration and excretion (movement, temp. maintenance etc.)
Why is controlling the quantities of fertilisers important?
- beyond a certain point they do not improve productivity
- environmental impacts
Define eutrophication
the process by which nutrient concentrations increase in bodies of water
