phosphorous and fertilisers

• Phosphorous has no gaseous reservoir instead its locked in phosphate ions within rocks. 
• It come from the sea but is brought to the surface by uplift. Weathering and erosion make the phosphate ions available. 
• Mycorrhizae are fungi that extend plant roots to increase the surface area for the absorption of minerals. They also hold water close to roots. 
• Where mineral ions are readily available plants develop earlier. This increases the rate of photosynthesis and yield. 
• Fertilisers reduce biodiversity. 
• Fertilisers leach into water sources and can poison people.