Chapter 13 - Energy + Ecosystems - (13.4) Use of natural and artificial fertilisers Flashcards
Why are fertilisers used as a farming practice?
It contributes to improved productivity
what do plants need in order to grow?
Mineral ions, especially nitrates, from the soil.
What does intensive production?
Concentrated on specific areas of land that are used repeatedly to achieve maximum yield from the crops and animals grown on them.
Why is intensive food production harmful?
It creates large demands on the soil because mineral ions are continuously taken up by the crops being grown on it.
These crops are either used directly as food or as fodder for animals that are then eaten.
Either way the mineral ions that the crops have absorbed from the soil are removed.
What occurs in a natural ecosystem?
Minerals are removed from the soil by plants but are then returned when the plant is decomposed by microorganisms on its death.
What occurs in agricultural systems?
The crop is harvested and then transported from its point of origin for consumption.
The urine, faeces and dead remains of the consumer are rarely returned to the same area of land.
Under these conditions the mineral ions concentrations will fall
It is therefore necessary to replenish these mineral ions because otherwise their reduced concentrations will become the main limiting factor to plant growth.
Productivity will consequently fall due to this
To offset this loss of mineral ions, fertilisers need to be added to the soil.
What is the difference between fertiliser used in natural vs artificial?
Natural (organic) fertiliser - consists of the dead and decaying remains of plants and animals as well as animal wastes such as manure, slurry and bone meal.
Artificial (inorganic) fertiliser - which is mined from rocks and deposits and then converted into different forms and blended together to give the appropriate balance of minerals for a particular crop.
Compounds containing nitrogen, phosphorus and potassium are almost always present.
What is the greatest long-term increase in productivity fertiliser?
Using a combination of natural and artificial fertilisers.
However, it is still important to add minerals in appropriate quantities as there is a point at which no further increases in the quantity of fertiliser no longer result in increased productivity.
How do fertilisers increase productivity?
Plants require minerals for their growth.
For example, nitrogen is an essential component of amino acids, ATP and nucleotides in DNA.
Both are needed for plant growth
Areas in which nitrate ions are available, plants are likely to develop earlier, grow taller and have a greater leaf area.
This increases the rate of photosynthesis and improves crop productivity.
It has been in no doubt that nitrogen-containing fertilisers have been considerable beneficial in providing us with cheaper food.
It has been estimated that the use of fertilisers has increased agricultura; food production in the UK by around 100% since 1955.
