Use of Hydrorock blocks for subsurface irrigation of orchards: "ASSIST - advanced subsurface irrigation system using Hydrorock”

Research output: Book/ReportReportProfessional


Stone wool is an inorganic material derived from molten rock characterised by its lightweight, low thermal conductivity and high porosity, being able to store around 95% of water. Hydrorock (HR) is a company focused on sustainable water management, using compacted stone wool in blocks as the basic application for all products of the company. Traditionally, the company has focused in flood management (drainage), but they want to explore if this material can be also used for subsurface irrigation. The “ASSIST - Advanced subsurface irrigation system using Hydrorock” project, aims to develop a new and cost efficient subsurface irrigation technology based on blocks of stone wool material (Hydrorock blocks), looking for a more efficient water use and higher crop yields, while saving on labour, operation and maintenance cost. The consortium of this project was formed by two Dutch private companies, Hydrorock International BV (HR) and Smart Farm Sensing (SFS) and Wageningen Environmental Research as knowledge institution. As a result of the project it can be stated that stone wool presents interesting water hydraulic properties, making this material unique in terms of capacity to store water and hydraulic conductivity. The density of fibres clearly affect the hydraulic properties of Hydrorock blocks, with a higher water retention capacity and hydraulic conductivity (Ks) for blocks with higher density. However, water release from Hydrorock blocks to the soil is mainly driven by soil properties (i.e. texture) and preliminary soil conditions (moisture) rather than by the block properties (density or fibre direction), since the hydraulic properties of stone wool largely differ from natural soils, especially for loamy and clay soils. Hydrorock blocks can be manufactured in multiple configurations, giving the possibility to adapt the system to several crop patterns and/or existing irrigation systems. The use of pressure compensated drippers to release the water within the block allow a better control of the water, providing more homogeneity in water distribution, within the block but also among different blocks of the irrigation unit. A total of two pilots were developed in Dubai and Bahrein to irrigate date palms on a sandy and loamy soil respectively. From the two pilots carried out during the project, we can state that with 10-30% less water applied to the Hydrorock blocks than in bubblers (control), Hydrorock blocks: • Achieve a similar yield but a higher water use efficiency. • Keep soil moisture in similar values, especially for deeper horizons (60-90 cm depths). • No present evidence of negative effects on date palms or the blocks after two years of operation. • No present evidence of salinity issues (if system is well managed with regular flushing events). • Present a lower cost of operation, specially related to weed removal. The use of machinery (i.e. harvesting) is also easier and creates less damage when compared to conventional surface irrigation systems, since the whole irrigation system is buried.
Original languageEnglish
Place of PublicationWageningen
PublisherWageningen Environmental Research
Number of pages45
Publication statusPublished - 2023

Publication series

NameReport / Wageningen Environmental Research
ISSN (Print)1566-7197


Dive into the research topics of 'Use of Hydrorock blocks for subsurface irrigation of orchards: "ASSIST - advanced subsurface irrigation system using Hydrorock”'. Together they form a unique fingerprint.

Cite this