BY5.8 Fertilisers

Nitrogen containing fertilisers:

• crop harvesting removes mineral elements
• cropping interrupts the naural cycle of nutrients
• nutrients can be replaced through the addition of fertilisers
• most fertilisers supply nitrogen, phosphorus and potassium
• use of fertilsiers has led to use of pooerer areas of land for agriculture
• overruse has led to environemtal problems
• minerals may be washed into waterwats and increase algae growth
• this contriutes to eutrophication

Problems caused by fertilisers:

• reduced specieis diversity in grasslands
  • fertilisers increase the growth of grasses and plants sucj as netle whch shade out smaller plants

• nitrates leaching into rivers
  • europhication is a natural process where the concentration of salts builds up in the water
  • the salts necessary for eutophication are mainly nitrates and phospahtes
  • leaching of these salts intot ehsurrounding land is a slow and natural porcess
  • but sewage and fertilisers are an additional source of salts

• nitrate is highly soluble and readily leached from the soil and washed into rivers
• this leads to algal bloom where the water becomes densely populated with species of algae as their growth is enhanced by the availability of nutrients
• the water becomes green and light is unable to penetrate it
• plants in deeper regions of water are unable to photosynthesise
• general decrease…