Use of natural and artificial fertilisers

Question 1

explain why fertilisers are needed in agricultural ecosystems

Answer 1

• crops are grown intensively and repeatedly on the same area of land
• mineral ions are taken up by the crops,which are then transported and consumed away from the land
• so the mineral ions they contain are not returned to the same area of land and so the levels in the soil are reduced which can limit the rate of photosynthesis
• so fertilisers need to be applied to replace them if photosynthesis/productivity is to be maintained

Question 2

what are the 2 types of fertiliser?

Answer 2

1- natural (organic) fertilisers

2- artificial (inorganic) fertilisers

Question 3

describe natural (organic) fertilisers

Answer 3

consist of the dead and decaying remains of plants and animals as well as animal wastes such as manure

Question 4

describe artificial (inorganic) fertilisers

Answer 4

mined from rocks and deposits then converted into different forms and blended together to give the appropriate balance of minerals for a particular crop- compounds containing elements nitrogen, phosphorous and potassium are almost always present

Question 5

research suggests that a combination of natural and artificial fertilisers gives the greatest long-term increase in productivity. However, it is important that minerals are added in appropriate quantities as

Answer 5

there is a point at which further increases in the quantity of fertiliser no longer results in increased productivity

Question 6

how do fertilisers increase productivity?

Answer 6

• plants require minerals for their growth
• Nitrogen is an essential component of amino acids, ATP and nucleotides in DNA
• both of which are needed for growth
• where nitrate ions are readily available, plants are likely to develop earlier,grow taller and have a greater leaf area