TCT and drift reduction
When applying crop protection products in open-field crops, drift into surface water, to nearby residents, and to non-target organisms must be minimized as much as possible. The Living Environment Activities Decree (BAL) therefore stipulates that, in many situations, you must use a spraying technique that achieves a specified level of drift reduction compared to a reference technique (in many cases, at least 75%). On this page, you can read about how spraying techniques and nozzles are evaluated, how a new technique is approved, and how the associated lists are related.
The Role of the TCT
The assessment of drift-reducing technologies and spray nozzles is the responsibility of the Technical Committee for Technology Assessment (TCT). As a manufacturer, you must submit measurement results for a new technology or nozzle to the TCT, which assesses—based on established measurement protocols—whether it meets the requirements for a specific drift reduction class.
The procedure is outlined in the Assessment System for Emission-Reducing Measures in Open-Field Cultivation. It explains how to submit an application, what research data is required, and how the assessment process works.
From Innovation to Recognition: The TCT Flowchart
For manufacturers and developers, it is not only important that drift reduction is established, but also how a new technology is ultimately incorporated into the DRT system. The TCT has drawn up a flowchart for this purpose.
The basic principle is simple: when applying crop protection products in open-field cultivation, you must always be able to demonstrate compliance with the legally required drift reduction standards. If a technique is already on the DRT list and you use it in accordance with the conditions specified in the corresponding information sheet, you can apply it immediately. If the technique is not yet on the list, the drift reduction must first be determined.
Strategies for supporting drift reduction
The flowchart describes various ways to substantiate the drift reduction achieved by a new technology:
- Research conducted in accordance with the Dutch measurement protocol. The most common approach is drift research conducted in accordance with the official Dutch measurement protocol for downward, upward, and lateral spraying techniques, carried out by an independent expert institute. You must then submit the results to the TCT for evaluation.
- Comparison with an existing DRT technology. If a new technology closely resembles one that has already been assessed, you can sometimes substantiate the drift reduction by comparing it to a technology already on the DRT list. The TCT also evaluates this substantiation.
- Use of an alternative testing method. International developments regularly lead to new measurement methods. If you wish to use a foreign or alternative testing method, you must submit it in advance to the TCT, which will assess whether the method is sufficiently comparable to the Dutch system.
- New technologies without an existing test method. For highly innovative technologies, a suitable test method may not yet be available. In such cases, you work with the TCT to determine how performance can still be objectively assessed.
More than Just Drift Reduction
A technology is not assessed solely on the basis of drift reduction. The flowchart also assesses compliance with the principles of Best Available Techniques (BAT): Do the proposed settings and conditions align with good agricultural practice? Is the technology effective? And is it feasible and verifiable in practice? A high level of drift reduction alone is therefore not sufficient; a technology must also be practically applicable and deliver good agricultural results under real-world conditions.
Opportunities for developing innovative technologies
For technologies still in the development phase, the flowchart includes a separate track. When the use of crop protection products is necessary for research and development, you can create room for development through a certified TNG company or in consultation with the Ctgb and the competent authority. This allows you to test new techniques before they are formally assessed for inclusion in the DRT system.
In doing so, the flowchart offers manufacturers, importers, and developers a transparent path from innovation to recognition. Especially with the rise of precision applications, sensor-controlled systems, spot sprayers, and future autonomous technologies, such a clear assessment framework is becoming increasingly important: the Dutch system allows room for innovation, provided that performance can be demonstrated and meets the requirements for drift reduction, effectiveness, and practical applicability.
The complete flowchart titled “Drift Reduction Spraying Techniques for the Application of Crop Protection Products in Field Crops” is included as an appendix to this article and is available via IPLO and the TCT documentation.
Drift-reducing techniques (DRT)
If a spraying technique receives a positive evaluation, it is added to the DRT list (Drift-Reducing Techniques). Techniques are classified into drift reduction classes, such as 75%, 90%, 95%, or higher. This classification applies exclusively under the conditions and parameters under which the technique was tested.
Each certified technology comes with an information sheet detailing its technical specifications, operation, application conditions, and prescribed settings—such as requirements for spray nozzles, air assistance, spray pressure, spray height, shielding, or other features. This information sheet is an integral part of the certification: you may only claim the corresponding drift reduction class if you use the technology in accordance with the described conditions. The information sheets help users apply the technology correctly and provide regulators with an objective basis for inspection and enforcement.
Please note: The DRT class does not automatically apply to a machine. The classification is linked to the machine’s specifications and to the conditions listed in the information sheet. Deviating from these conditions may result in the required drift reduction no longer being achieved.
Drift-reducing nozzles (DRD)
Spray nozzles can also be assessed individually. Certified nozzles are included on the DRD list (Drift-Reducing Nozzles) and are classified into the 50%, 75%, 90%, and 95% drift reduction classes, based on measurements taken at specific pressures and settings.
The certification of a drift-reducing nozzle is valid for five years. After that, manufacturers must demonstrate that the nozzle still meets the requirements; therefore, the DRD list includes an expiration date for each nozzle.
Both technology and seed rate determine the outcome
The final drift reduction is often determined by the combination of sprayer, application technique, and spray nozzle. Sometimes, a particular application technique can only achieve the required drift reduction with a specific class of drift-reducing nozzle. Therefore, always refer to the combinations listed in the DRT and DRD lists and the accompanying data sheets; this is the only way to determine which drift reduction class you are actually permitted to use.
Drift-Free Techniques (DVT)
Current regulations for open-field cultivation are based on demonstrating drift reduction compared to a reference technique; the BAL stipulates that in many situations, a minimum of 75% drift reduction must be achieved. However, drift is not an issue in every application. With some techniques, due to the nature of the product or its mode of action, there is no significant drift into the surrounding environment, and in such cases, a drift reduction percentage relative to a reference technique is not always logical or necessary.
That is why the proposal is to introduce a separate category of Drift-Free Techniques (DVT) alongside the existing DRT system. Drift-free techniques are methods used to apply crop protection products in solid or liquid form, whereby the nature of the product and its mode of action prevent drift from occurring.
Assessment by the TCT
Just as with drift-reducing technologies, the TCT could also evaluate drift-free technologies. The focus here is not on the extent to which a technology reduces drift, but rather on whether emissions into the environment can reasonably be ruled out under normal operating conditions. This assessment can be based on a technical analysis of the operating principle, supported by technical documentation, field demonstrations, photo and video material, and, if necessary, limited verification measurements. Based on this, the TCT assesses whether a technology qualifies for inclusion on a future DVT list.
Supplement to the existing DRT system
The introduction of drift-free techniques does not alter the existing DRT system. Drift-reducing techniques remain the basis for assessing spraying techniques where drift may occur; a DVT list supplements this for techniques where drift is effectively eliminated. This creates a logical and future-proof system in which both drift-reducing and drift-free techniques are appropriately integrated, allowing room for innovation while ensuring the protection of people, the environment, and surface water.