Current rates of water use in the UK strawberry industry are already unsustainable and water supplies in the future will be even more limited, according to leading experts.
Despite this, many growers continue to apply more irrigation water than the crop needs, but over-watering can increase disease, reduce fruit shelf life and dilute important flavour compounds because of high berry water contents, they claim.
A study at East Malling Research (EMR) is developing new practical ways for growers to apply irrigation more efficiently. In 2008, the HortLINK programme compared three different methods to determine how field-grown strawberries could be irrigated more effectively.
Crop evaporative demand was estimated with an Evaposensor, changes in the vertical profile of soil moisture content were measured by EnviroSCAN probes and changes in soil moisture across the rooting zone were measured with Decagon probes, the so-called Closed Loop system. The amount of irrigation water needed to maintain yields and berry quality was calculated in each of these three strategies and compared with two treatments using irrigation for 30 minutes or an hour each day to represent current conventional methods.
Once gathered, information from the 2008 season showed that yields of Class 1 fruit were improved by all three scheduling treatments, compared to the commercial controls, and that yields of up to 10.3 tonnes per acre could be achieved. These regimes also proved the most frugal in terms of irrigation water applied and used less than 25 per cent of the irrigation water used by many commercial growers.
The report states: “If irrigation is applied effectively, scheduled, water savings of up to 75 per cent can be delivered compared to current ‘best practice’ without reducing yields. Berry sweetness can also be improved.
“Current abstraction rates in the major strawberry growing regions are unsustainable and new legislation (The Water Act 2003) will limit future water use. Our experiments with potted strawberries have shown that significant water savings can be achieved if irrigation is scheduled effectively.”
Dr Mark Else, research leader at EMR, told freshinfo: “The fact that we can reduce water use by such a large margin without affecting yield or quality is the most exciting thing to come from this research.
“Further developmental work is needed before irrigation can be applied and adjusted automatically to meet the crops’ needs, but both the Closed Loop method and the EnviroSCAN could be used to develop an irrigation control system that would simplify irrigation scheduling.
“We’re at the start of the third year of the five year project and we will soon be testing the techniques on commercial growers’ sites who are keen to give them a try.”
No comments yet