Primary aim of the fertilization is obtain the optimum yield from the crops. Fertilizers contains soil, organic matters, macro nutrient, micro nutrients. it has relatively low pH.
Fertilizers are mainly three types
Chemical
Organic – natural or biological origin compost, crop residue, goat dung, cattle dung, green manure, leaf litter, rice husks
- Organic fertilizers advantages – improve the physical properties of the soil, better aeration and permeability, decreases the soil crust, improve tilth, improve the fertility status of the soil (slow release of the nitrogen, prevent the leaching of the non water soluble nutrients
- Organic fertilizers disadvantages – contain less nutrient than the inorganic fertilizers, require large quantities, High transformation cost, composition may vary, improperly process fertilizers may contains plant pathogens.
Bio-fertilizers – large population of specific group of microorganisms incorporated aseptically into sterile carrier materials.
Plant nutrients
Plant mineral nutrients are removed from the by
- Removal of the harvested crop
- Leaching during rain and irrigation
- Gaseous evaporation loss nitrogen as NH3
- Via soil erosion.
There are 17 chemical elements
| C,H,O | Non mineral, obtain via photosynthesis (sugar, starch) |
| N,P,K | Primary nutrient – plants are used in large amounts, since soil nutrient deplete rapidly, hance fertilization is must. |
| Ca,Mg,S | Secondary nutrients – sufficient amount is available in the soil therefore added to fertilizer is not necessary |
| B,Cu,Zn,Mo,Mn,Fe,Ni,Cl | Micro nutrients |