A fertiliser is something that helps plants grow bigger and/or faster. The main elements needed in fertilisers for plants are nitrogen, potassium and phosphorous. The Haber process, which makes ammonia on a large scale is a key process in the manufacture of fertilisers.
Problems from over use of fertilisers (eutrophication)[edit | edit source]
Many fertilisers contain nitrates, and as these are very soluble, these nitrates can be leached away by rain water, going into streams, lakes or other bodies of water (note that the sea will usually not have this problem). The nitrates provide nitrogen for algae and plants. Therefore, the algae may grow so much that the water becomes green, and the plants lower down in the water do not have enough light. These therefore die since they cannot photosynthesize. Eventually, the algae also dies. This all provides massive quantities of food for bacteria, which means their population increases. These bacteria use up oxygen by respiration, and therefore animals die from lack of oxygen. Untreated sewage also causes this problem.
Preventing these problems[edit | edit source]
- Only apply fertilisers to land where plants are growing. This means the nutrients are taken up straight away.
- Not apply too much fertiliser, so there is none left over as the plants don't need it all
- Not apply fertiliser just before it rains
- Use manure instead of fertilisers, as it breaks down slower and releases nitrogen over a long period of time. It also adds humus to the soil. This improves its texture and can reduce erosion.
Fertilisers help plants to grow by using a series of minerals with members of the periodic table in them. Some times problems are caused of the side affects they have to come.