Different methods of Fertilizer application
Application of fertilizer uniformly on the soil surface is known as broadcasting of fertilizer. This is done either before sowing of the crop or in the standing crop (top dressing). Broadcasting is the most widely practiced method in India due to ease in application.
Broadcasting is advantageous with solid and soluble fertilizers.
Broadcasting and Incorporation. Generally, the entire dose of a phosphatic and potassium
fertilizer is applied by broadcasting before sowing. Because of their low mobility in soil, these fertilizers are incorporated into the rooting zone.
Application of fertilizers in narrow bands beneath and by the side of the crop rows is known as band placement of fertilizers. Band placement is done under the following
(I) when the crop needs initial good start,
(2) when soil fertility is low,
(3) when fertilizer materials react with soil constituents leading to fixation, and
(4) where volatilization losses are high.
Depending on the root system, fertilizer band is placed directly beneath the seed or by the side of the row. For crops like castor, redgram, cotton etc., with tap root system, fertilizer band can be 5 cm below the seed. In cereals and millets, which produce fibrous root system, it is advantageous to place fertilizers 5 cm away from the seed row and 5 cm deeper than the seed placement.
Placement of fertilizers near the plant either in a hole or in a depression followed by closing or covering with soil is known as point placement of fertilizers. It is adopted for top dressing of nitrogenous fertilizers in widely spaced crops.
In sugarcane, two or three holes are made around the clump and nitrogenous fertilizers are placed in the holes and closed. Similarly, soil near tobacco plants is scooped and fertilizers are placed and covered with soil. This method is adopted to get high recovery of fertilizer nitrogen. Since the crop roots occupy only a small fraction of soil in the early stages, it is not advisable to apply to the entire field by broadcasting.
Urea supergranules and urea briquetts are placed in the reduced zone by pressing
them into the mud in between the hills of rice plants.
It refers to the placement of fertilizers in the subsoil with the help of high power machinery. This method is recommended in humid and subhumid regions where sub-soils
are acidic Fertigation. Application of fertilizers with irrigation water is known as fertigation. Straight an mixed fertilizers containing N, P and K easily soluble in water, are allowed to dissolve in the irrigation stream.
The nutrients are thus carried into the soil in solution. This saves the application cost and allows the utilization of relatively inexpensive water soluble fertilizers. Usually nitrogenous fertilizers are most commonly applied through irrigation water. It is generally followed with drip irrigation.
Application to plant
The roots of the seedlings are dipped in nutrient solution before transplanting. In
soils deficient in phosphorus, roots of rice seedlings are dipped in phosphorus slurry before
Application of fertilizers to foliage of the crop as spray solution is known as
foliar spray of fertilizers. It is also called non-root feeding. These solutions may be prepared in a low concentration to apply any one of plant nutrient or a combination of nutrients.
This method is suitable for application of small quantities of fertilizers, especially micronutrients. Major nutrients can also be applied by this method when there is not adequate moisture in the top layer of soil.
Among the nutrients N is most frequently foliarly applied. Absorption of N by foliage I
more rapid and nearly 80% of the spray material is absorbed by most of the crops within 24 hours of application