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- Subject: Science
- AS: AS90766
- Level: 2
- Credits: 4
- External
Science 2.8 Describe the chemical properties and effects of fertilisers
Subject content
The purpose of this assessment is to look at general chemical principles in the context of fertilisers. Your class work will involve practical work appropriate to level two and involves a range of skills and principles. The fertilisers will include but not be limited to inorganic fertilisers, for example superphosphate, urea, ammonium nitrate, ammonium sulphate, potassium sulphate, and organic fertilisers, for example manures, blood, and bone.
The properties of fertilisers will be limited to:
- ionic bonding – in a crystal lattice
- pH – measurement, release of H+ ions
- solubility – relationship to polarity of water molecule, effect on formulation for application (eg slow release fertilisers)
- melting point and boiling point
- percentage composition
- availability of ions to plants.
Check out this site that describes the effect of soil pH on availability of nutrients.
The effects of fertilisers will be limited to the chemistry of the:
- elements in plant growth (N, P, K, S, Mg, Co, Mo, B)
- soil particle charge in holding and releasing ions
- ions in pollution and eutrophication.
