FOLIAR NUTRITION AND FERTILIZERS
Nov 01, 2016

Foliar application is a technique of feeding plants by applying liquid fertilizer directly to their leaves. Plants can absorb nutrients through the leaves, foliar nutrition can supplement the parts that can not absorb enough from the soil by the plant roots. 

Foliar application of macronutrients can help plants recover from temporary stress due to moisture problems, pests or disease.Foliar application has been shown to avoid the problem of leaching-out in soils and prompts a quick reaction in the plant. Of the micronutrients, foliar application of phosphorus, zinc and iron brings the greatest benefit in comparison with addition to soil where phosphorus becomes fixed in a form inaccessible to the plant and where zinc and iron are less available.

Foliar fertilizers are applied directly to leaves. The method is almost invariably used to apply water-soluble fertilizers and used especially for high value crops such as fruits and vegetables.

Foliar application fertilizer materials must be soluble in water. Most of these are salts and when applied in too high concentration the solution will cause "burning" of the plant tissue. Often the safe concentration of the fertilizer material in the solution is so low that repeated applications are required to supply the needs of the plant. This is especially true of nitrogen, phosphorus, and potassium. 

Foliar applications become soil applications if excess solution is applied or if rain falls shortly after application. This results in inadequate absorption of the nutrient by the foliage and loss of time, machinery use and labor for the application of the material. However, it is not a complete loss as some of the material that gets to the soil will be absorbed by the plant roots. 

Foliar fertilizer are not compatible with all insecticides, fungicides, etc. If mixed with incompatible materials, loss of effectiveness of the fertilizer, the insecticide, etc. , or of both may result. In addition, this may also increase the danger of burning to the plant.