Question 81
Plants need nitrogen to make proteins and grow. Farmers used to add compost and manure to soil to increase the amount of nitrogen in it. Fertiliser is made from ammonia, which contains nitrogen. Often the ammonia is converted into nitric acid and then into a nitrate salt. However, nitrates are soluble in water. When it rains, excess fertiliser runs off fields into rivers and lakes. This causes eutrophication. Find out what eutrophication means and what damage it causes.
