Fertilisers Flashcards
Give 3 uses for fertilisers.
Increase crop yield
Increase productivity
Ensure plants get the correct amount of nutrients
Why does farmland soil become unproductive?
Crops are harvested and replanted in the same area, meaning that nutrients are constantly taken up from the soil and are not replenished.
Compare the accuracy of application of natural and artificial fertilisers.
Artficial fertilisers can be applied in more precise concentrations
Natural fertilisers are bulky so may be harder for them to be applied
Compare the speed that natural and artificial fertilisers work at.
Natural fertilisers work more slowly
Artificial fertilisers work more quickly.
Compare the cost of natural and artificial fertilisers.
Natural fertilisers are cheap/free
Artificial fertilisers are more expensive
How do nitrogen containing fertilisers increase plant gowth?
They increase the amount of amino acids/bases in the plant, which are needed for DNA production. This leads to greater plant growth, leading to larger leaves and more photosynthesis.
Why might nitrogen containing fertilisers reduce species diversity?
Which type of plant do nitrogen rich soils favour?
Nitrogen soils favour grasses. This means grasses grow faster and outcompete other plants for things such as light/space, so they die
Name 2 things reduced species diversity leads to.
Less habitats
Less niches
What is leaching?
Rainwater dissolves nutrients so they are washed out of the soil where plants can reach, and are carried deep underground.
What is eutrophication?
Nutrients enter water and their concentration increases.
How can leaching affect drinking water?
Leaching causes nutrients to be carried into lakes. If the lake is used for drinking water, the water then becomes toxic.
- Name the factor that limits growth of algae in water.
Low nitrate concentration.
- How does leaching change the concentration of nitrates in a lake?
Leaching causes ion concentration to increase.
- Which factor no longer limits, causing algae to grow?
Nitrate ion concentration no longer limits.
- What are algal blooms and why do they occur?
Algal blooms are a rapid mass growth of algae. They are at the surface of the lake, so they receive the most light and grow the quickest.
- At lower depths of the lake, what is the limiting factor?
What happens to the plants at the bottom?
Light limits at the bottom of the lake.
This means they die
- Why does the population of saprobionts increase?
Saprobionts have a lot of food as there are many plants for them to decompose. Food is no longer a limiting factor.
- Why does demand for oxygen increase?
Demand for oxygen increases as population of saprobionts increases
- How does the waters oxygen and nitrogen concentration change?
Oxygen concentration decreases as saprobiontic demand grows.
Nitrogen concentration increases as it is released from decaying organisms.
- Why do aerobic organisms start to die?
Oxygen becomes very limited.
- Why do anaerobic populations start to rise?
Many aerobic organisms have died as there is very little O2, meaning there is no competition.
- High anaerobic organism population causes what to happen to nitrate concentration and water?
Nitrogen conc rises further as organisms decay.
This turns water toxic and putrid.
