Renewable Farming

U. of Nebraska research proves benefits of foliar nutrition

Foliar feeding season is coming up fast — and here’s one of the most comprehensive research presentations we’ve seen, documenting benefits of foliar-applied nutrition. Here, we summarize a presentation by the University of Nebraska’s Dr. Roch Gaussoin, based on years of his research on foliar feeding.

May 24, 2021 — The 137-slide presentation, titled “Foliar Feeding DOES work” was presented at an AgriEnergy Solutions seminar, documents how you can enhance crop yields and health with foliar-applied nutrition. We presented this report a few years ago, but it’s more timely now as many growers are searching for ways to coax another 10 to 40 bu. of corn yields from this season’s crop. We’ve also field-tested foliar feeding for more than a decade, focusing on ways that WakeUP amplifies leaf coverage, rapid absorption and accelerated translocation of nutrients into crop metabolism.

We split the presentation into “takes” of 30 slides or fewer, so you can download sections of it quickly. We converted the PowerPoint presentation into PDF (Portable Document File) format, so anyone with Adobe Acrobat Reader can open and read it. We suggest that you print out the PDF of each slide section… the whole show is a “keeper” worthy of a 3-ring binder in your farm office.


This report offers highlights which are more fully explained in the full presentation.

Key points from slides 1-30

1. Foliar uptake of nutrients has been documented thoroughly.

2. It’s a misconception that foliars enter through stomata. They enter through the cuticle via “nanopores.” These leaf pores are called “Ectodesmata” and are very small; less than one nanometer. Solutes such as urea move through readily. (A WakeUP colloid is about 0.8 nanometer)

3. Uncharged molecules move readily when in solution, but not if they’ve dried on the leaf surface. So it’s important for nutrient elements to penetrate quickly, within a few seconds.

4. Increased hydration (more water) improves penetration (permeation) because it weakens ionic charges of the nutrients.

5. Nutrients absorbed through leaves enter cell walls the same way as ions absorbed by roots. The myth that leaves can’t absorb nutrients has been disproven for decades.

6. Foliar-applied nitrogen is 30% to 99% absorbed. (Yet, one of our Iowa clients heard an extension agronomist tell him, “Leaves can’t absorb nitrogen. Only roots can.”)  Soil-applied nitrogen is only 10% to 40% recovered.  Up to 90% of soil-applied N is lost to groundwater leaching.

7. Surfactants are beneficial to critically important.

8. Spray solution pH should be slightly acidic to neutral. Leaf nanopores are negatively charged, so a chelator is beneficial to neutralize the positive charge of most micronutrient metals (manganese, zinc, etc.) 

9. Foliar-applied nutrients are immediately available to plant metabolism.

10. Foliar applications allow for varying rates depending on the crop’s analyzed need for nutrients.

11. “Organic facilitators” bind substantial amounts of nutrient metals. These include humic acids, fulvic acids, glucoheptinates, amino acids, citric acid, and others (look closely at the important slide on this subject).  WakeUP Summer performs the job of an “organic facilitator” because it’s formulated with plant based oils, alcohols, and oleic acids.

12. Using plant-based or organic sources as foliar nutrient complexing agents is beneficial because they are “less phytotoxic” and provide an energy source to microorganisms.  

 Here’s the link to download the first 30 slides.


Key points from slides 31-60

Soybean leaf sprayed with nutrients without WakeUP in spray solution

1. In a normal application of NPK foliars on grass, 70% of the nutrients are absorbed into plant metabolism after two hours. (Our commentary: WakeUP Summer accelerates this penetration. Leaves will appear dry within 10 to 20 minutes because the glossy spray coat has been absorbed.)

Bean leaf sprayed with WakeUP in solution is “clear coated”

2. Calcium and Magnesium are absorbed more slowly, but most other metal micros are quickly taken up.

3. Spraying time of day makes little difference in absorption. Temperature is probably more important. Ambient temps around 70 degrees are favorable, and a little later in the day usually brings slightly warmer temps. [Editor’s note: We’ve learned to avoid spraying at temperatures over 80 degrees F. We favor early morning first, even when dew is on plants. WakeUP quickly disperses dew, which helps with leaf coverage and complete absorption of nutrients. Second choice is late in the day, when temps are lower and winds are often abated.]

4. The nitrate form of nitrogen is more quickly absorbed through leaves and into plant cells than the urea form. The carrier or surfactant will influence speed of absorption.

 Here’s the link to download the second 30 slides.


Key points from slides 61-90

1. Foliar feeding can amplify movement of photosynthetically built carbohydrates to the roots. About half of leaf carbohydrates are sent to growing points. The other half flows to roots, which excrete to the soil about half of the nutrients they receive. Soil organisms use this energy to break down mineral nutrients which plants take up. Also, mycorrhizal fungi thrive on the energy exuded by roots, amplifying nutrient and water uptake. 

2. Foliar nutrient absorption is physical and chemical — and happens quickly.

3. Foliar feeding is especially helpful if root structure is poor, crops are stressed (such as dry weather), or you have pH problems in the soil which block uptake of certain micronutrients. (Our comment: See the slide showing how availability of micronutrients varies by soil pH)

4. Even with optimum soil fertility, there’s not always a continuous supply of nutrients to the plant.

5. Foliar fertilization is by far the most effective way to apply secondary and trace elements. [Editor’s note: most herbicides chelate (lock up) trace elements such as boron, zinc, manganese and others. That’s what causes “yellow flash.” A foliar spray with those traces can shorten the “pause” in growth after hitting a crop with glyphosate or glufosinate.]

6. By making essential micronutrients available, foliar feeding can increase uptake of soil fertility, reducing total fertilizer needed. 

7. Foliar nutrients increase chlorophyll production, which in turn increases uptake of soil-applied fertilizer. 

8. Early, cold and wet conditions constrain soil organisms and hamper soil nutrient availability. Foliar feeding gives nutrients immediately, jump-starting growth until soil warms up.

Here’s the link to download the third 30 slides.


Key points from the fourth group of 14 slides

1. Check the label on the foliar nutrient product to see if you need a buffering agent.  If you are tank-mixing several products, a buffering agent may help.

2. Check pH with a reliable meter or pH paper.

Here’s the link to download the fourth take, which is 14 slides.


Key points from the fifth group, which is 16 slides

1. Phosphite salts are sometimes being recommended to increase plant health and resist soil pathogens.

2. Phosphite is not considered a nutrient which substitutes for the typical forms of phosphorus fertilizers. 

Here’s the link to download the fifth take, which is 16 slides.


Key points from the final group of 18 slides

1. The University of Nebraska is experimenting with organic acids which could be foliar applied to amplify certain growth processes like root development.

2. Low dose, frequent foliar applications have definite agronomic benefits. 

Here’s the link to download the sixth and final take, which is 18 slides.