Applying foliar fertiliser may appear to be a relatively new phenomenon, but did you know that the ability of plants to absorb water and nutrients through their leaves was discovered more than three centuries ago? Foliar fertilisers have therefore been applied in agriculture already since the early 19th century.

Why use foliar fertilisers?

There are various reasons to treat agricultural- and horticultural crops with foliar fertilisers, with the most important reasons being:

1. To quickly correct a nutrient deficiency during growth; foliar fertilisers usually have an effect within a few days.

2. To guarantee the nutrient requirement is met when the uptake of nutrients via the soil is limited.

3. To protect and feed the crop in a single application; in most cases foliar fertilisers can be combined with a crop protection treatment.

4. Providing nutrients to the crop within the limits of the legally permitted standards such as maximum dose rates of nitrogen, phosphate and animal manure.

Important conditions

The effectiveness of foliar fertilisers varies widely among different crop-types. For an optimal application, the following factors are important:

• Plant characteristics: each plant species has its own characteristics. Plants with water-repellent leaves (various brassicas) or a thick waxy layer absorb water and nutrients less easily. The growth stage of the plant is also important. Most plants absorb nutrients best during the vegetative growth phase.
• Weather conditions: plants absorb foliar fertiliser most efficient when the foliar spray does not dry out too quickly. The ideal moment for a treatment with a foliar fertiser is therefor a high relative humidity, a mild temperature, not too much sun and a low wind speed. Hence, preferably spray a foliar fertiliser in the early morning or late evening.
• Quality of the foliar fertiliser: organically complexed foliar fertilisers have a greater stability in the spray-tank and are also more easily absorbed than a fertiliser containing non-complexed nutrients.

Risks

Spraying a foliar fertiliser is not always without risks. Leaf burn is one of the most common consequences of incorrect spraying. Leaf burn is usually the result of an excessive dosage, or a result of the foliar fertiliser drying too rapidly on the leaves. The miscibility can also be an issue, not all foliar fertilisers can be combined with other products. Soiltechs foliar fertilisers are developed not only for efficacy but also for plant safety and compatibility. Check the instructions for use for information on the miscibility or consult your supplier.

Complexed foliar fertilisers

The Soiltech portfolio offers a wide range of liquid foliar fertilisers. These foliar fertilisers are organically complexed, a unique quality of Soiltech's Optima range of foliar fertilisers. This means that the active nutrient (e.g. manganese or copper) is bound to an organic molecule. An organically complexed fertiliser offers several advantages over a non-complexed or chemically complexed fertiliser:

• The fertilisers are safe to use and scores excellent towards crop safety.
• The active nutrient is easily absorbable via the leaf.
• The fertiliser has greater stability and can be more easily combined with other substances in a tank mix.

Research

The R&D department at Soiltech is continuously developing new formulations, and has a professional greenhouse which is used to study the safety and efficacy of foliar fertilisers. An automated spraying installation enables highly accurate dosage. Soiltech tests the safety of foliar fertilisers in the greenhouse on crops including radishes and beans, because these crops are sensitive to burning and scorching. Following extensive screening in the greenhouse, field trials are conducted on crops in practical situations.

Would you like more information about the combinability of Soiltech's (foliar) fertilisers and/or biostimulants? Click here!