Foliar nutrients are widely used in agriculture and horticulture for correcting deficiencies and supplying regular doses of key elements to aid crop development and improve harvest quality.
Although foliar nutrition can be a more precisely targeted method of delivering the crop’s requirements than bulk fertilisers applied to soil, it can be a challenge to achieve rapid uptake through the leaf surfaces.
The main methods of entry are through the stomata (mainly on the undersides of leaves in most plant species) or through the waxy cuticle on the upper leaf surfaces. Environmental conditions at the time of application favouring stomatal opening help with uptake through this route, and applications should be made if possible during periods of high humidity, and not at times of high sunlight or heat intensity.
Studies by leading foliar nutrition experts such as Victoria Fernandez (Technical University of Madrid)¹ and Tom Eichert (Bonn University)² have shown that absorption through the wider leaf surfaces is greatly helped by wetting the whole surface rather than depositing large droplets, and by extending the drying time (humectancy) of the spray droplets, as nutrients move more easily through the cuticle when in solution.
Unfortunately, the typical soluble salt formulations used in most foliar nutrients have poor wetting and spreading characteristics, little better than water in many cases. Including appropriate adjuvants in the formulations themselves presents difficulties with compatibility, and is difficult to get right since these materials are used at a wide range of rates and water volumes.
A better approach is to add a purpose-made adjuvant to the final spray solution. Tests at the OMEX research facility have shown major improvements in leaf wetting by the addition of NA13 to a wide range of commonly used products.
Use NA13 with the products listed in the table below if the nutrient would otherwise be used alone or in tank mix with another nutrient. If the nutrient is being tank mixed with pesticides then it is not necessary to include NA13, although inclusion will improve uptake of all products in the mix. Avoid using NA13 in tank mixes with selective herbicides.
Use 0.1% dilution with foliar nutrients in a minimum of 200 l/ha water.
The spray tank should be filled with half the required water. Add the required amount of NA13 to the water before adding any nutrients, maintain constant agitation. Add remaining water to correct dilution and spray.
¹ See Foliar Fertilization, Scientific Principles and Field Practices, V. Fernández, T. Sotiropoulos and P. Brown, published by the International Fertilizer Industry Association, 2013. Available on line at http://www.fertilizer.org
² See Uptake and Release of Elements by Leaves and Other Aerial Plant Parts, by T. Eichert and V. Fernández, Chapter 4 of Mineral Nutrition of Higher Plants, Ed. P. Marschner, 3rd Ed. 2012.
Do not apply in tank mix with pesticides when crop is showing deficiency symptoms, is under stress, or in adverse weather conditions.
NA13 is particularly effective when used with Bio 18, Bio 20, DP98, the Folex range, Manganese 17.5 and Superphite Plus at 0.1% rate of the total volume.
Turf and Amenity
NA13 is added to the spray tank to maximise the uptake of most foliar nutrients.
It is recommended for tank-mix application with Green Cross and P-Phite Turf, to maximise the uptake of the active ingredient into the turf and ensure maximum root growth.
NA13 acts as a powerful surfactant, spreading the nutrients evenly over and round the sprayed surface, ensuring it is absorbed rapidly and effectively and improving rainfastness.
Trials comparing plant responses with and without NA13 have shown better results and greater nutrient efficiency where it is used, producing a bigger increase in rooting and more effective nutrient uptake.
|When to use
||How much to use
|To increase nutrient uptake
||0.1% of spray volume
||Required with application of Green Cross and P-Phite Turf