Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. 3.  We need more food to feed increased population. This is only possible through high yielding varieties of food grains and other food materials like Oilseeds, Sugar, Fruits etc. All these things need nutrition through roots - from soil. These nutritions in large quantity can only be fortified to soil through use of Chemical fertilizers. 4.  Excess or uncontrolled use can spoil the soil properties, Osmotic pressure, Conductivity and water holding capacity. It may also affect adversely on population of microorganisms and other parameters. It can also damage water resources.