Plants and Nitrogen
Chemistry: AQA GCSE Higher, topic 10.4.1
Plants and Nitrogen
Plants provide humans with a crucial food source and remove carbon dioxide from the atmosphere (using photosynthesis). In order to grow, plants need to make proteins, and this requires nitrogen.
Plants can't absorb nitrogen gas
- Although nitrogen gas is abundant in the atmosphere (there is lots of it), plants cannot use nitrogen in the air.
Plants absorb nitrates
- Instead, plants absorb soluble nitrates (nitrogen-containing compounds) from the soil.
Harvesting crops removes nitrogen
- Nitrates re-enter the soil when plants die.
- But, harvesting crops takes this nitrogen out of the system.
- So, farmers should manually add nitrogen back into the soil.
Test yourself on Plants and Nitrogen
Why do plants need nitrogen to grow?
Why do plants absorb nitrates from the soil instead of using nitrogen gas from the air?
What would most likely happen to a plant's growth if the soil around it ran low on nitrates?
Why must farmers add nitrogen back into the soil after harvesting their crops?
What would happen to the nitrogen content of a field's soil if a farmer harvested crops every year without adding fertiliser?