Plants need mineral salts from the soil for healthy growth. In nature, plants die, decompose and mineral salts return to the ground.
When crops are harvested, the plants are removed, there is no decomposition, and the quality of the soil decreases as less nutrients become available.
Manufactured fertilisers are added to the soil to replace those that are lost. This enables healthy crops to grow quickly, but at a cost to the farmer.
Why do farmers want to harvest crops quickly?
What do fertilisers contain to help plants grow?
Lack of Nitrogen causes
Yellowing of leaves.
leaves on lower parts of the plant may die
Weak stem meaning the plant cannot grow tall.
Lack of Potassium causes ….
1. Yellowing of leaves
2. Poor fruit growth.
Lack of Magnesium causes leaves to turn yellow from the bottom of the plant upwards
Leaf from the bottom of a plant
Leaf from the top of a plant
Lack of Phosphorus causes ….
1. Purpling of leaves
2. Poor root growth
3. Small plant size
Copy out the diagrams from p63 Co-ordinated Biology (second Edition) showing nutrient deficiency in plants