Why Does an Iron Sulphate Application Make Moss Go Black?
Iron sulphate blackens moss by disrupting its cellular processes and structure, ultimately inhibiting photosynthesis. Here’s how it works:
1. Cellular Damage:
When iron sulphate is applied to moss, the iron ions are absorbed into the moss’s tissues. These ions disrupt the moss’s delicate cell structure, particularly in the chloroplasts, which are responsible for photosynthesis. This leads to cellular damage and degradation of chlorophyll, the green pigment critical for capturing sunlight.
2. Oxidation Reaction:
The iron in iron sulphate oxidises when it comes into contact with moisture in the moss and the surrounding environment. This oxidation process forms iron compounds that are dark in colour. These compounds coat the moss’s surface, further disrupting its ability to absorb light.
3. Loss of Photosynthetic Capability:
Photosynthesis relies on light absorption by chlorophyll. As the moss turns black from the iron coating and chlorophyll degradation, it can no longer effectively absorb sunlight. Without photosynthesis, the moss cannot produce the energy it needs to survive.
4. Dehydration Effect:
The iron sulphate also dehydrates the moss by altering its water-retaining properties. This combined with the inability to photosynthesise accelerates the moss’s death.
This dual action—disrupting chlorophyll and coating the moss in blackened iron compounds—makes iron sulphate an efficient moss control method. The blackened moss is a clear sign that it is dying and ready for removal.
