METHODS OF FERTILIZER APPLICATION The different methods of fertilizer application are as follows: a) Broadcasting It refers to spreading fertilizers uniformly all over the field. Suitable for crops with dense stand, the plant roots permeate the whole volume of the soil, large doses of fertilizers are applied and insoluble phosphatic fertilizers such as rock phosphate are used. Broadcasting of fertilizers is of two types. i) Broadcasting at sowing or planting (Basal application) The main objectives of broadcasting the fertilizers at sowing time are to uniformly distribute the fertilizer over the entire field and to mix it with soil. ii) Top dressing It is the broadcasting of fertilizers particularly nitrogenous fertilizers in closely sown crops like paddy and wheat, with the objective of supplying nitrogen in readily available form to growing plants. Disadvantages of broadcasting The main disadvantages of application of fertilizers through broadcasting are: i) Nutrients cannot be fully utilized by plant roots as they move laterally over long distances. ii) The weed growth is stimulated all over the field. iii) Nutrients are fixed in the soil as they come in contact with a large mass of soil. b) Placement It refers to the placement of fertilizers in soil at a specific place with or without reference to the position of the seed.
Placement of fertilizers is normally recommended when the quantity of fertilizers to apply is small, development of the root system is poor, soil have a low level of fertility and to apply phosphatic and potassic fertilizer. The most common methods of placement are as follows: i) Plough sole placement In this method, fertilizer is placed at the bottom of the plough furrow in a continuous band during the process of ploughing. Every band is covered as the next furrow is turned. This method is suitable for areas where soil becomes quite dry upto few cm below the soil surface and soils having a heavy clay pan just below the plough sole layer. ii) Deep placement It is the placement of ammoniacal nitrogenous fertilizers in the reduction zone of soil particularly in paddy fields, where ammoniacal nitrogen remains available to the crop. This method ensures better distribution of fertilizer in the root zone soil and prevents loss of nutrients by run-off. iii) Localized placement It refers to the application of fertilizers into the soil close to the seed or plant in order to supply the nutrients in adequate amounts to the roots of growing plants.
The common methods to place fertilizers close to the seed or plant are as follows: a) Drilling In this method, the fertilizer is applied at the time of sowing by means of a seed-cum-fertilizer drill. This places fertilizer and the seed in the same row but at different depths. Although this method has been found suitable for the application of phosphatic and potassic fertilizers in cereal crops, but sometimes germination of seeds and young plants may get damaged due to higher concentration of soluble salts. b) Side dressing It refers to the spread of fertilizer in between the rows and around the plants. The common methods of side-dressing are Placement of nitrogenous fertilizers by hand in between the rows of crops like maize, sugarcane, cotton etc., to apply additional doses of nitrogen to the growing crops and Placement of fertilizers around the trees like mango, apple, grapes, papaya etc. c) Band placement If refers to the placement of fertilizer in bands. Band placement is of two types. i) Hill placement It is practiced for the application of fertilizers in orchards. In this method, fertilizers are placed close to the plant in bands on one or both sides of the plant. The length and depth of the band varies with the nature of the crop. ii) Row placement When the crops like sugarcane, potato, maize, cereals etc., are sown close together in rows, the fertilizer is applied in continuous bands on one or both sides of the row, which is known as row placement.