Deposition and droplet spectrum

Why Danfoil can deliver small droplets - with control and efficient penetration

The bottom line

With Danfoil’s spray technology, droplet size and droplet spectrum are primarily controlled by air pressure— not by water volume—so you can focus on crop coverage and drift control through the right air setting for the job.

Why “small droplets”—usually a problem—and why they don’t have to be

Small droplets are attractive because they provide more uniform coverage and better deposition on the leaf. The challenge with conventional spraying technology is that the finest droplets can be difficult to control and are more easily affected by wind. In Danfoil’s system, the droplets are energized by the airflow, which helps them reach the target and penetrate the crop.

Rule of thumb

Air pressure = droplet size (and deposition/penetration) • Water volume = concentration & capacity (but does not change the droplet spectrum when air pressure is kept constant).

The droplet spectrum depends on air pressure—not water volume

The compendium describes that the droplet spectrum from the Eurofoil® atomizer is, in practice, independent of the water volume (within normal operating ranges), as long as the air pressure remains unchanged. This means you can choose a water volume that suits the task and conditions without “ruining” the spray pattern—it’s the air setting that makes the difference.

What happens when you change the air pressure?

Lower air pressure → coarser droplets and lower risk of drift (typically relevant for bare soil/low crops and "difficult" wind conditions).
Higher air pressure → finer droplets and better coverage/deposition, while the airflow aids penetration in denser crops.

The point is not “as much air as possible”—but the right amount of air for the task, so that the crop is gently moved without being “pounded down.”

Documentation in the compendium: moisture-sensitive paper in the crop

The compendium describes experiments with water-sensitive paper placed at the top, middle, bottom, and on the ground within a crop. The experiments clearly show that changes in air pressure result in significant changes in droplet size and the amount of small droplets—and that the droplets are deposited throughout the crop when the setting is correct.

Practical takeaway

When you want to improve placement and penetration: start with the air setting. A higher water volume is not a shortcut to better placement if the air setting doesn’t match the task.

How to use this in practice

1) Look at the crop and growth stage

Air pressure must be adjusted according to the crop’s height, density, and development. Denser crops often require more energy/air to ensure penetration and placement at both the top and bottom.

2) Consider wind and direction

In headwinds, the throw distance may be reduced—so boom height and air settings should be adjusted. The right combination is about keeping drift down while still hitting the target effectively.

3) Keep an eye on the "balance"—

Too low air pressure → risk of insufficient penetration in dense crops.
Too high air pressure → the crop may "close up," and you lose effectiveness + may increase the risk of drift.

The goal is an air pressure that causes the crop to move slightly—so the droplets are “worked into” the crop.

If you want to dive deeper into the specific technology behind the system, start here: