fertilisers Flashcards
why are fertilisers used?
to replace the nitrate and phosphate ions lost from harvesting plants for crops from the nitrogen cycle.
what are the 2 types of fertilisers?
natural and artificial
natural fertilisers
e.g. manure
usually cheap and free if the farmer has animals.
cons- cannot control exact minerals and proportions of these minerals.
artificial fertilisers
inorganic compounds created with specific amounts of minerals.
inorganic compounds are more soluble so can dissolve in the water surrounding the soil- plant can take up more nitrate and phosphate ions
cons- high solubility of minerals means they dissolve in rain and large quantities of minerals are lost
environmental impacts- leaching and eutrophication.
leaching
water soluble compounds are washed out and into rivers/ponds
eutrophication
nitrogen fertilisers are washed from fields and into rivers/ponds
causes growth of algal blooms, which block light
plants below cannot photosynthesise, so they die.
bacteria within the water respire and break down dead plant matter
increase in bacteria- more oxygen within water used for respiration.
eventually, fish and other aquatic organisms die due to lack of dissolved oxygen within the water.