Greenhouse 5

Half of Greenhouse 5 at the Al Dahra farm in Al Ain was converted to EPIC in December 2010. The other half stayed on its existing surface drip system as the control, both halves were metered, and the crop on both was cucumber grown for local markets.

The farm owner and the local municipality wanted to make local food production more efficient and were looking at alternatives to surface drip. About 80% of water in the UAE is used for agriculture. Under drip, fertiliser also tends to seep down and away from the root zone, which costs the farm money and puts groundwater at risk of contamination.

Trenches were dug by hand and lined with Firestone EPDM. Ten rows of plants in five sections each got an independent EPIC chamber, connected to the drain header to make a closed loop, then covered with fine gravel and sweet sand. A reservoir tank with a submersible pump supplies the water, and a 90 degree elbow on the drain header sets the level. Fertiliser is dissolved in the reservoir and carried through the system, while trace elements are applied to the leaves.

On the most recent of the two cucumber crops grown after conversion, the drip half used 370 m³ of water and the EPIC half used 55 m³. Water per kilo of cucumber fell from 40 to 3 US gallons, yield per plant rose from 3.57 to 7.22 kg, and fertiliser use fell from 92 to 50 kg. For the 2011 crop, the daily meter log from 17 April to 3 July records 67.2 m³ on EPIC against 403.2 m³ on drip, a saving of 83%.