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THE DROUGHT ISSUE: When is a drought, not a drought?

Publication Date: 
27 July 2018

When there is 'enough' water

Who decides when Great Britain is in a drought?

In an article on the 11 July, AHDB's Dr Nicola Dunn, a water specialist in our Resource Management team, said that "...hot weather and low rainfall has resulted in an agricultural drought."

While bodies such as The Environment Agency and Hydrological Outlook UK are still using terms such as 'prolonged dry spell' and 'heatwave'.

However, The National Drought Group (NDG), chaired by the Environment Agency’s Chief Executive, met on Monday 23 July.

In a statement they said:

"We are in a continuing period of prolonged hot and dry weather. June 2018 was the driest June since 1925, with a rainfall total for England of only 15 mm.

One water company, United Utilities, has announced its intention to impose a hosepipe ban (“Temporary Use Ban”) in parts of the North West from 5 August. The other water companies do not currently intend to introduce hosepipe bans, and there is no threat to essential public water supplies. But continued dry weather into autumn could see the risk of some further restrictions and further environmental impacts across the country.

The water companies, the Environment Agency and others are taking action to reduce the risk of further water restrictions and to ensure that water users and the environment itself continue to get the water they need. Participants agreed to step up their activity on all fronts."

On 19 July, the Scottish Environment Protection Agency Water Scarcity Report increased the alert levels for some regions.

Where water reports are available:

Build your own picture using the AHDB weather hub

Of course, the issue for growers is not the general water availability picture, but whether water can get to crops.

In the July 20 issue of Potato Weekly, we revealed the proportion of the GB crop with irrigation available this season is 49%.

So, with over half the country's potatoes relying on rainfall alone  - a look at the 'long term rainfall analysis' tab on the AHDB Weather Hub shows just how dry this year has been.

Looking at the Eastern Scotland, North East and Central regions on the map above, areas where there are large numbers of potatoes growing, in each region June and July 2018 are showing as the driest June and July ever.

By way of example, the Central region has seen 14mm of rain in the two months combined, though at the time of writing there are still 4 days remaining in the month (and thunderstorms forecast). The next driest two month period for that region was the famous drought year of 1976, which 'enjoyed' over twice as much rain during the same period with 35mm.

The AHDB Weather Hub brings together open-source and procured weather and related data from four key providers including the Met Office, EA, SEPA and Agrii. The tool includes information on air temperatures, rainfall, relative humidity, sunshine duration, wind speed, soil moisture (at 10, 30 and 60cm depths), soil temperature and solar radiation. Explore and use the weather hub here​.

The irrigation picture on our SPot Farms

Will Gagg, Farm Manager Strategic Potato Farm North:

“In the last two months we’ve emptied three reservoirs, we’ve never even emptied one before! It is the equivalent of a year and half’s water, by comparison last year we used about a third of one reservoir.

“We’re doing everything we can to preserve water, including irrigating mostly at night and using boom irrigators (rather than rain guns) wherever possible to avoid evaporation.

“It is so dry that we’re having to do some irrigation in the day too. We had a thunderstorm last night and one field caught 14mm of rain. I’ve just been walking there and you wouldn't know it had rained at all.

“Yields will certainly down, I’d estimate as much as 25% across the farm. We have about 10% of our potato land that is unirrigated and on those fields we will be looking at very small yields and very small potatoes!”

In a report from SPot Scotland Kerr Howatson said that Bruce Farms (Perthshire) have been irrigating far more frequently than normal, he commented:

"[irrigation] is absolutely vital at the moment to keep the soil moisture deficit from rising too high, so the best advice would be to top up little and often. There is no point putting on significant quantities of water only to see your efforts literally evaporate into the air."

While in Suffolk, Andrew Francis said that work conducted last year as part of the SPot programme has help him, and others who have engaged with it:

“After the work we did last year through the SPot Farm programme, we now know our varieties better. We conducted a trial on irrigation and common scab control, and we were able to use the knowledge gained to know which of our varieties can last a day or two longer without an irrigation, and which we need to target more regularly.”

Read reports from Strategic Farms here:

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