This subject will be covered fully later. However, it is important for you to know that plants need elements such as potassium, nitrogen and phosphorus to grow properly. Some elements are needed in large amounts and others in small amounts. Different plants also have different needs.
Plants need a balance of nutrients. If one element is in short supply then the growth and development of the whole plant will be affected, no matter how abundant the other nutrients are.
Some nutrients occur naturally in the soil. These are absorbed by the plants through their roots. When nutrients are lacking in a soil they can be added by applying artificial fertilizers such as super phosphate. Too much fertilizer can damage plants cause them to burn off.
Nutrients taken up by plants are returned to the soil when leaves and other organic matter decomposes in the soil. Animal urine and manure also contai many plant nutrients.