Proper nutrition is required for maximizing the yield, health, and fruit quality of mango trees. Unlike many other fruit species, the mango tree’s nutritional demands are highly specific and fluctuate significantly as it progresses through its life stages. A successful fertilization program must be precisely matched to the tree’s current growth phase, delivering the correct balance of macronutrients and micronutrients when they are needed most.
Essential Nutrients and Fertilizer Selection
The three primary nutrients, Nitrogen (N), Phosphorus (P), and Potassium (K), are required in different proportions depending on the tree’s age. Young, non-bearing mango trees need a more balanced ratio, such as a 1:1:1 NPK formulation, to fuel rapid vegetative growth and root development. As the tree matures and begins to bear fruit, the focus shifts, requiring a formula with reduced nitrogen and significantly higher potassium, often moving toward a ratio like 8-3-9 to support fruit filling and quality. High nitrogen levels in mature trees can interfere with flowering and fruit set, so potassium becomes the dominant nutrient to increase fruit size, flavor, and color.
Mango trees frequently exhibit deficiencies in specific micronutrients. Zinc (Zn) is required for cell development, and a deficiency can result in leaf chlorosis and poor fruit set. Iron (Fe) and Manganese (Mn) are essential for chlorophyll production, and a lack of either causes interveinal chlorosis, especially in new leaves. These deficiencies are often corrected through foliar sprays, as high soil pH can make these elements unavailable to the roots. Selecting a commercial fertilizer that includes these minor elements, or supplementing with organic materials like compost and manure, helps ensure a complete nutritional profile.
Fertilization Schedule Based on Tree Age
The timing of fertilizer application is important for mango trees because their nutritional requirements change dramatically between the vegetative and reproductive cycles. Young, non-bearing trees benefit from frequent, small applications to encourage continuous growth. Applying a balanced fertilizer monthly or every eight weeks during the growing season promotes the quick establishment of a strong root system and canopy. This frequent schedule ensures a steady supply of nitrogen to drive vegetative flushes.
Once the tree reaches the mature, bearing stage, the fertilization schedule must align precisely with the fruiting cycle to manage yield. A major application of fertilizer, particularly one high in potassium, is recommended immediately after the harvest to replenish depleted nutrients and prepare the tree for the next season’s bloom. Subsequent, smaller applications can be split throughout the year, often at the start and end of the rainy season, to maintain health.
Nitrogen-heavy fertilization should cease during the period leading up to flowering and during the actual bloom to encourage fruit set rather than new leaf growth. The reproductive phase benefits from foliar applications of potassium nitrate to aid in flower induction and fruit retention. Applying a potassium-rich fertilizer in multiple small doses during the fruit-filling stage is beneficial for increasing fruit size and quality.
Practical Application Techniques
Determining the correct amount of fertilizer is often based on the size of the tree, using simple rules of thumb to calculate the annual dosage. The required amount of certain nutrients can be calculated based on the tree’s trunk circumference. Alternatively, a general guideline suggests gradually increasing the total annual fertilizer quantity from 5–10 kilograms for a young tree to 50 kilograms for a tree over ten years old. This calculated annual amount is then split into the prescribed applications throughout the year.
Granular fertilizer should be spread evenly on the soil surface within the critical root zone, which extends from a distance away from the trunk out to the drip line. It is important to maintain a distance of 45 to 90 centimeters from the trunk to prevent fertilizer burn. The fertilizer should be lightly incorporated into the top few inches of soil or applied in a ring around the tree canopy to maximize uptake.
Alternative methods, such as fertigation, deliver nutrients through the irrigation system, allowing for highly precise and efficient delivery directly to the roots. For specific deficiencies, especially those involving micronutrients like zinc, foliar feeding is the preferred technique, where a diluted nutrient solution is sprayed directly onto the leaves for rapid absorption. Regardless of the method used, fertilizer application must be followed by irrigation to help dissolve the nutrients and move them into the root zone, preventing root burn and ensuring maximum absorption.