WENR30 – Advanced SubSurface Irrigation System using rockwool (ASSIST)

Aanleiding van het project

Water is a precious resource that should manage with the most precautions. Agriculture usually suppose between 70-80% of the water withdrawal. The use of modern irrigation technologies allow us to apply the exact amount of water (and nutrients) required by the plants. However, most of the farmer still use old and inefficient systems. This project aim to develop a new and costly efficient irrigation and water management technology, looking for a more efficient water use and higher crop yields, while saving on labour, operation and maintenance cost.

Hydrorock (HR) is a company focused on sustainable water management. Rockwool is the basic application for all products of the company. HR is specially developed rockwool for water management, as a climate adaptive solutions for water management. The type of rockwool used has a characteristic that it can absorb 95% water of its own weight. That is why it is, among others, suitable as buffer material for water. Moreover, the material also releases water fast to the environment. For the time being, HR was mainly focused in flood management (drainage), thanks to the capacity of their elements to absorb the water from the saturated soil and delivered into drainage pipes. At this moment, HR is active in two areas:
1. Drainage, buffer and infiltration
2. Decoupling of sky water (houses)
Recently, multiple clients have been asking HR if the material can also be used for irrigation. This project aims to investigate if those elements can be used for precision irrigation, providing the required water for crops directly into the root zone, minimizing water losing though direct evaporation or leaching. HR has special interest to test this technology in water scarce areas, such as Middle-East and old Persia, where either water has become so limited that it threatens agricultural production or where modern irrigation techniques are still not widely implemented.

Doel van het project

The aim of the project is to develop a new technology for sub-surface irrigation of crops to save water and reduce operational cost specially adapted (but not limited) for water scarce regions. This technology will be based in the use of the rockwool aquifer blocks developed by HR, in the SFS technology to remotely monitor and operate the system and in the knowledge and tools from WUR to maximize crop production against the lowest water use (water productivity) To achieve this goal, the following sub-objectives are pursued:
• Adapt the current aquifer blocks to be used as a commercial sub-surface irrigation device (from TRL 3-4 to TRL 6-7).
• Optimal design of the irrigation system and test its performance compared with other traditional irrigation methods through a pilot located under semiarid conditions (Dubai).
• Develop a remote monitoring and control system to operate the irrigation scheme in the most efficient way (when to apply water and how much)
• Asses the costs/ benefits of the current irrigation system
• Asses the movement of water between the rockwool and different soils types (and vice versa) in order to re-design the current aquifer blocks into a new subsurface irrigation device suitable for a large spectrum of regions (TRL 6-7). The possibility to use the system as a dual irrigation/drainage system (reverse drainage) will be also assessed.

Omschrijving van de activiteiten

1) Asses the most relevant parameters for adapting the current HR elements for irrigation and design a system to monitor and operate the irrigation scheme.

2) A pilot to test the HR elements and the Monitoring and Operational system is developed in Dubai under a semi-arid conditions (date palms).

3) Lab experiments with different type of soils and Modelling for new type of irrigation elements, suitability for dual irrigation/drainage system.

4) Cost benefit analysis.

Verwachte resultaten

1) A report with a detailed description of the potentiality of the HR elements to be used for irrigation and a pilot lay-out to test the HR elements and the Monitoring and Operational system.

2) A report with the main results from the Pilot.

3) A report on the optimization of the use of rockwool material for irrigation under different conditions and as a dual irrigation/drainage system.

4) Prototype – A new elements is constructed based on Lab experiments and ready for its testing on field conditions.

5) A report with a cost benefit analysis is developed


The aim of this innovation is to develop a more efficiency subsurface irrigation technology, able to provide the required water to the crops while minimizing the water losses by direct evaporation or infiltration. Since the technology is already developed for other purposed, with this innovation we aim to move from a TRL3-4 to a TRL6-7 at the end of the project.
Up to now, the HR elements were not designed or previously used for the purpose of irrigation. This project will assess the suitability of this technology while new innovations are required, in order to adapt the elements to the concrete characteristic of irrigation.
In order to monitor and operate the system, a remotely control system is required. To do that, several innovations are required, in order to adapt the traditional control systems used in irrigation to a one able to measure and control at the same time the water levels in the delivery elements (aquifer blocks) and in the soil, in order to provide only the water required by the plants. This technique has not been applied before and has a great potential for water scarce areas.
Although it is not the core of the project, the system could be also suitable as a dual drainage-irrigation device (reverse drainage), providing or draining water according to the soil conditions. This innovation could be very useful in other context such as The Netherlands, where more drought related problems are occurring during the last years. For example, there are already some developments in Brabant where subsurface soil irrigation is being used for irrigation. In the Bavaria brewery they are using subsurface drainage pipes for irrigation. To improve and optimize these types of systems even more, this research could contribute by gaining knowledge on subsurface irrigation systems.
Regarding the (long term) environmental and health consequences of using rock wool underground, Hydrorock International BV has already the required certifications.


1) Report describing the potential use of rockwool for underground irrigation and lay-out for testing.
WEnR, HR, SFS and other interested partners (open source) to benefit from it.
This information could be used by interested parties to develop new irrigation related products and technologies
based on rockwool
2) Report with the main results from the pilot.
WEnR, HR, SFS and other interested partners (open source) to benefit from it.
HR and SFS can validate the functioning of their system for future commercialization. Other interested parties can
develop new irrigation related products and technologies based on rockwool.
3) Report on optimization.
WEnR, HR, SFS and other interested partners (open source) to benefit from it.
Interested parties can develop new irrigation related products and technologies based on rockwool.
4) Prototype HR.
HR will have a new product for potential commercialization after further development.
5) Cost benefit analysis.
WEnR, HR, SFS and other interested partners (open source) to benefit from it.
This could be used by project partners to scale up the takeover of the technology by other interested parties.