Transcript of Fertilisers - A2 Biology
Brainstorm Are they Good Or Bad Disadvantages Fertilisers Notes Case Study - The USA African Hunger Case Study Objectives (cc) photo by Metro Centric on Flickr (cc) photo by Franco Folini on Flickr (cc) photo by jimmyharris on Flickr EU Fertilisers (cc) photo by Metro Centric on Flickr Why are fertilisers needed in agricultral ecosystems? How do natural and artificial fertilisers differ? How do fertilisers increase productivity? What are fertilisers used for? Providing plants with nessesary minerals such as nitrogen Fertilisers are needed to acheive the the high crop yields demanded by developed worlds In natural ecosystems the minerals removed from the soil are retured when the organism is broken down by microrganisms. Plants require many nutrients Nitrogen Magnesium Phosphorus Potassium In agriculture the crops are harvested and removed taking the nutrients with them. Two types of fertilisers Natural Dead and decaying remains of plants and animals Animal wastes such as manure and bone meal Artificial Mined from rocks and deposits These are blended together to create a compound These are suited for particular plants Fertilisers often contain Nitrogen Phosphorus Potassium Key Words How can fertilisers help improve their lives Provide higher crop yield More crops to sell and a higher income Help prevent famine Natural Fertilisers Cattle Slurry Tank Cattle Slurry being sprayed over crops Reduced Species diversity Soils favour rapidly growing species such as grasses and nettles Leaching The process by which the soil is washed out of nutrients Eutrophication The build up of nutrients in bodies of water, and naturally occurs in freshwater lakes This increase in nitrogen creates an algae bloom (massive increase in algae population) This prevents light getting into the lower depths causeing other plants to die Reduces the limiting factors for the growth of saprobiotic bacteria. These grow exponentially, using the dead organisms. Saprobiotic bacteria require oxygen for respiration creating a demand. However the concentration of oxygen decreases and increases the nitrates are released from the decaying organisms Oxygen becomes a limiting factor for everything in the lake that respires aerobically, these organisms die Anaerobic organisms have less compertitions so therefore the population increases These further decompose dead material, releasing more nitrates and some toxic wastesFull transcript
Such as: Hydrogen Sulphide This makes the water putrid and uninhabitable Think of three example! Natural (organic) fertilisers Aftificial (inorganic) fertilisers Species Diversity Leaching Eutrophication Algae Bloom Saprobiotic organism Aerobic Anerobic Summary Name four different types of natural fertiliser. What are the main environmental effects of using nitrogen fertilisers and what is there effect on the environment?