Foliar fertilizers .....Article (Issue # 50)

DESPITE BEING an agricultural country, at present Pakistan imports agricultural products from various countries of the world. Mostly our agricultural products have surplus of chemical fertilizers in it. They not only damage our agricultural products but also cause serious effects on human health. The new agrochemical technology to solve this problem is the use of Foliar Fertilizers.

Foliar fertilizers are an excellent way to revive and stimulate stressed, tired, or diseased plants, correcting soil deficiencies and for the addition of micronutrients. The agrochemical technique of feeding a plant through the leaves using foliar fertilizers has proved to be the most valid one to complete traditional soil fertilization as well as to carry out curative treatments. They are mixed specifically for foliar feeding, optimizing nutrient uptake through stomata (plant pores) in the leaves. Sometimes soils that have high pH or low pH, certain nutrients become unavailable for uptake into the plant in the soil. However with the foliar spraying they can get the minerals into the plant until they make corrections to the soil.

Since foliar absorption is limited because of the relative barrier of the cuticle, it is not possible to solely feed plants via the leaves. The foliar fertilizer should be applied as a fine mist. Scheduling of foliar fertilizer that when it should be applied is also important. Spraying early in the morning, while it is light, but temperatures are still cool or in the evening is best and conditions that allow the leaf to dry rather than stay wet for an extended length of time is also important to consider. Foliar fertilizers should not be applied during hot, bright conditions, if the plants are wilting or under water osmotic stress as the plants stomata are likely to be closed making application ineffective.

Foliar feeding can be carried out on a regular, weekly basis, or can be limited to the times when the crop comes under high nutrient demand such as early fruit set and heavy fruit loading. Often the greatest response to foliar feeding will occur during the active growth phases of plants. During these active growth stages, leaves show a particularly high efficiency for absorbing nutrients.

In soil less systems such as hydroponics, imbalance in the combination of nutrients, pH levels, poor physical properties of the media surrounding the root zone, deficiency of iron or any situation which damages the root systems or restricts its growth, development or physical process such as respiration, affects the uptake of minerals or in the presence of any plant pathogens, foliar feeding has its greatest advantage.

Foliar applications can be targeted to a particular stage of crop development to achieve specific objectives and is an excellent way to fine tune a high fertility program. It provides an insurance policy against yield and quality loss limitations in root mineral absorption and transportation. Crops such as capsicum, potatoes and tomatoes have shown both yield and fruit quality improvement when they are given foliar feed.

So it is a quick and efficient way of addressing nutrient deficiencies in crop plants, have greater uptake efficiency as compared to soil application, an effective method of overcoming various factors that reduce the nutrient uptake of the plant and ensure balanced absorption of essential nutrients.

With the help of foliar fertilizers our farmers will not only be able to meet their domestic needs adequately, but they can also contribute to the economy of the Pakistan by making it an exporting country.

http://www.technologytimes.pk/mag/2010/dec10/issue04/foliar_fertilizers.php