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level: 13.5 Environmental issues of nitrogen-containing fertilisers

Questions and Answers List

level questions: 13.5 Environmental issues of nitrogen-containing fertilisers

QuestionAnswer
Positives of nitrogen-containing fertilisers- Essential component of biological molecules such as proteins + is needed for growth - This increases rate of photosynthesis - Improve crop productivity - Cheaper food
Negatives of nitrogen-containing fertilisers- Reduced species diversity - Leaching, which may lead to pollution of watercourses - Eutrophication, caused by leaching of fertiliser into watercourses
Reduced species diversity- Because nitroglycerin-rich soil favour the growth of grasses, nettles and other rapidly growing species - These out-compete many other species, which die as a result
Leaching- Process by which nutrients are removed from the soil - Rainwater dissolves soluble nutrients, like nitrate ions, + carry them deep into the soil - The leached nitrate ions find their way into watercourses, like streams, rivers, lakes - They may have harmful effect on humans if river or lake is source of drinking water - High conc. of nitrate ions in water can prevent efficient oxygen transport in babies + link to stomach cancer - They can cause eutrophication
Eutrophication- Process where nutrients increase in concentration in bodies of water
Eutrophication process (1)- Mineral ions leached from fertilised fields stimulate the rapid growth of algae in ponds and rivers (algal bloom) - Nitrate ion con. become limiting factor for growth - Large amounts of algae block light from reaching the plants below
Eutrophication process (2)- Light becomes limiting factor for growth - Eventually the plants die because they're unable to photosynthesise enough - Saprobiontic bacteria feed on the dead plant matter
Eutrophication process (3)- The increased numbers of bacteria reduce the O2 conc. in the water by carrying out aerobic respiration - O2 becomes limiting factor for growth - Fish + other aquatic organisms die because there isn't enough dissolved O2