An innovative irrigation method being tested in Gozo by local scientists could drastically reduce the amount of water needed to irrigate plants and trees.

The clay-based system involves placing clay elements close to the crops’ root zone. As the surrounding soil dries out, it creates a pressure differential and suction draws water out of the clay elements. The clay’s specific porosity controls the rate of water release, ensuring a slow and steady flow that caters to the crops’ needs.

Researchers led by the Eco-Gozo directorate within the Gozo Ministry are testing out the technology - a variation of a Self-regulating, Low Energy, Clay based Irrigation (SLECI) system that is also being piloted in Portugal and Morocco.

A SLECI system at work.

The initiative is being implemented in three pilot locations: the Government Experimental Farm in Xewkija, as well as two fields in Għarb and Xagħra. Researchers are specifically studying two essential crops: vines and citrus trees.

In Għarb, researchers are using low water emitters (releasing less than 1 litre of water per day) to irrigate vines. In Xagħra, citrus trees are irrigated using high water emitters (releasing less than 3 litres of water per day). Similar to the Xagħra pilot site, vines in Xewkija are irrigated using high water emitters (with a slightly lower capacity, releasing less than 2.5 litres of water per day).

Encouraging results are emerging from the initial trials at two of the Gozo sites, Għarb and Xagħra.  Data collection from the third site is still ongoing. While crop yields from both SLECI and conventional drip irrigation methods appear to be comparable, the water usage with SLECI is demonstrably lower. In fact, early data suggest that irrigation using SLECI technology requires approximately half the amount of water than in conventional drip irrigation.

The clay elements used in the SLECI irrigation system being tested.

Aside from reduced water consumption, SLECI systems also eliminate wasteful water runoff, minimise evaporation, help suppress weed growth thanks to their precise water delivery and promote nutrient retention by delivering water directly to the roots.

Furthermore, once installed, the system operates autonomously, providing water only when necessary.

Local researchers testing the SLECI system are doing so as part of the MED-WET project, which in Malta is funded by the Malta Council for Science and Technology through the EU-backed PRIMA initiative.

MCAST is a project partner leading communication and dissemination efforts.

The MED-WET project is also running tests on the use of constructed wetlands in Egypt that treat wastewater for irrigation purposes, and on the use of a solar desalination greenhouse which uses renewable energy to convert brackish water to a new source of freshwater for irrigation. The latter project is also being piloted in Gozo.

The MET-WET project will conclude in October 2024.

Francesca Busuttil is a researcher working on the MED-WET project at MCAST. This article is brought to you by the Malta Chamber of Scientists.