Broadcasting: Application of fertilizer uniformly on the soil surface is known as broadcasting. This is done either before sowing of the crop or in the standing crop. Broadcasting is advantageous with solid and soluble fertilizers.
Broadcasting and Incorporation: Generally, the entire dose of phosphatic and potassium fertilizers are applied by broadcasting before sowing. Because of their low mobility in soil, these fertilizers are incorporated into the rooting zone.
Band Placement: Application of fertilizers in narrow bands beneath and by the side of the crop rows is known as band placement of fertilizers. Depending on the root system, fertilizer band is placed directly beneath the seed or by the side of the row.
Point 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.
Sub-soil Placement: Refers to the placement of fertilizers in the sub soil with the help of high power machinery. This method is recommended in humid and sub-humid regions where sub soils are acidic.
Fertigation: Application of fertilizers with irrigation water is known as fertigation. It is generally followed with drip irrigation.
Root Dipping: 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 planting.
Foliar Spray: Application of fertilizers to foliage of the crop as spray solution is known as foliar spray of fertilizers. This method is suitable for application of small quantities of fertilizers, especially micronutrients.
Time of Application of Fertilizers
The time of application mainly depends on :
Crop uptake pattern
Soil properties, nature of the fertilizer material
Utilization of carbohydrates
Nitrogen, phosphorus and potassium are taken in large quantities in early stages of crop growth. The uptake of nitrogen is slow at the later stages which is generally met from the soil by mineralisation. Legumes require until nodules are formed. Potassium is taken gradually throughout the growth and development of the crop.
Soil Properties and Nature of Fertilizers
Nitrogenous fertilizers are soluble and highly mobile in soil. Nitrogenous fertilizers are lost into deeper layers beyond root zone if the entire quantity of fertilizer is applied especially in light textured soils. Phosphatic fertilizers are highly reactive are fixed in the soil and become immobile. Potassic fertilizers are less mobile since they are adsorbed on the clay complex. The entire quantity of phosphatic and potassic fertilizer are therefore applied in one dose at the time of sowing.
Utilization of Carbohydrates
Under a sufficient level of nitrogen in the plant, carbohydrates are utilized for synthesis of proteins. The assimilation of nitrogen requires energy which is obtained either from light or the breakdown of carbohydrates. The time of application of nitrogen, therefore, depends on the end product of the crop.
Basal Application: Application of fertilizers before or at the time of sowing is known as basal application.
Split Application: Application of recommended dose of fertilizers in two or three splits during crop period is known as split application of fertilizers. The number of split applications has to be more in light soils and less in heavy soils. Nitrogen is applied in more splits for long duration crops.
Application of fertilizers in the standing crop is known as Top Dressing.
Balanced Fertilization: Balanced fertilization refers to application of N, P, K nutrients to the soil in quantities to bring the balance in nutrients in the soil to meet the requirement of any specific crop. It does not refer to balance or equal proportion of nutrients in a fertilizer.