Fertilizers

Fertilizers

More than twelve elements such as carbon, oxygen, hydrogen, nitrogen, phosphorus, potassium calcium, magnesium, iron, zinc, manganese, molybdenum, sulphur, etc., are essential for the normal and healthy growth of plants. These are called plant nutrients. Nitrogen, phosphorus and potassium are the essential plant nutrients consumed in large quantities. Continuous cultivation from the soil makes it poorer and poorer in materials supplying nitrogen, phosphorus and potassium to plants and become less productive and ultimately infertile. Thus, in order to maintain soil fertility, it is necessary to add materials containing nitrogen, phosphorus and potassium in the form of fertilizers. Fertilizers are of two types. 1. Natural Fertilizers 2. Artificial Fertilizers

Natural Fertilizers:-These contain animal waste such as blood, bones, horns, lather waste, fish scrap, excreta, night soil, sewage sludge, tankage, guano, etc., and decayed plants such as cotton seed meal, wood or tobacco stem ashes, oil cakes and green growing plants buried in the soil, etc.

Artificial or Chemical Fertilizers:- Chemical substances which are added to the soil as to make up the deficiency of essential elements are called chemical fertilizers.

Substance to be used as fertilizer must have following characteristics. It should (i) be soluble in water. (ii) Be fairly stable. (iii) Be easily assimilated by plants. (iv) Not disturb pH of the soil. (v) Be cheap.

Nitrogeneous Fertilizers:-  the important nitrogeneous fertilizers are :- (i) Ammonium suplhate. (ii) Calcium cyanamide. (iii) Calcium ammonium nitrate. (iv) Basic calcium nitrate. (v) Urea.