|Foliar fertilization involves the application of soluble fertilizer to the foliage of crop plants, in the form of a diluted aqueous spray. From the applied solution, the plant takes up the nutrients in ionic form, through the leaves and other aerial organs. Supplying plants with adequate nutrition is an important aspect of maintaining their health and performance, and foliar sprays have been used for a long time as a source of the necessary nutrients. Foliar sprays can give your crops a nutritional boost that results in increased yields higher quality, improved resistance to disease and insect attack, and enhanced drought tolerance.
When to use Foliar Fertilization?
- When root activity is impaired and ineffective because of poor aeration, low soil temperature, nematodes, rodents, etc.
- When the nutrient availability in the soil is reduced - Certain soil conditions, such as high pH, excess moisture, low water content, low temperatures, etc., may render nutrients unavailable to the plant root.
- When deficiencies need a quick correction or prevention - When a shortage of a nutrient is indicated by tissue analysis or visual observation foliar fertilization provides the quickest means to correct the deficiency, as nutrient uptake through the foliage is considerably faster than through the roots.
- When the roots cannot provide the plant with sufficient nutrients in the critical stages of growth - Peak demand for nutrients can exceed the supply, and foliar applications can be timed to coincide with specific vegetative or fruiting stages of growth, and the fertilizer formulation can be adjusted accordingly. Foliar fertilization delivers essential nutrients at key growth stages, when the plant can utilize them most effectively.
- When top quality of crops is desired - Foliar sprays at late growth stages can specifically improve the final quality of agricultural produce.
- When increased pest and disease resistance is desired - It is well known that foliar fertilization with phosphorus and potassium can reduce the development of several diseases in many crops, while improving the yield and quality.
Tips for efficient Foliar Fertilization
- The best times for foliar spraying are early morning and late afternoon, when humidity is highest and the leaves are in a state of complete turgor, with their cells full of water.
- Avoid foliar spraying during the hot part of the day: absorption at high temperatures is very poor, and plants may be exposed to stress and scorching.
- Dew formation after foliar application is an important aid to prolonged penetration, because of re-solubilization of the fertilizers by the dew collected on the leaves.
- Spraying should be done under minimal wind conditions. This is especially important with finely atomized sprays, as they drift readily.
- Always spray when there is adequate soil moisture, when the leaves are turgid and far from water stress. Consider irrigating on the day prior to spraying.
- Avoid foliar spraying just before rain or overhead application of irrigation, to prevent the sprayed material being washed off.
- The optimal pH of a foliar spray is slightly acidic (5 +/- 0.5).
- Use of a suitable wetting agent or surfactant decreases the surface tension of the spray drops, which leads to enhanced spreading of the drops, increases the wetted surface area, reduces burning/scorching of the leaves, and improves the uptake of the product. Always check the compatibility of the surfactant with the foliar fertilizer.
- Ensure that the fertilizer is fully soluble.No special equipment is required - foliar solutions can be applied with conventional spray equipment, e.g., fan sprayer, backpack sprayer, sleeve sprayer, aerial sprayer, etc.
- Select the appropriate spray volume and pressure for each crop. Using the correct volume of spray is essential for achieving full coverage of the plant canopy.