A DROUGHT strategy on an extensive light land estate at Euston, near Thetford, has involved major changes to cropping.

After harvesting just 600kg of wheat an acre, estate manager Andrew Blenkiron has cut the area of irrigated crops by almost 20%. The impact on the Duke of Grafton’s estate was severe because a large area of wheat was drilled after sugar beet.

With an average wheat yield of 1.2 tonnes – although September-sown varieties yielded 2.25 tonnes, close to the estate’s five-year rolling average – Mr Blenkiron’s team drills all cereals as early possible.

A 60m gallon reservoir is proposed, which with the existing 110m gallons of winter storage, would irrigate about 1,400 acres. In three years in five there was enough water but five years ago, significant investment was made in a reservoir and underground mains.

Mr Blenkiron has cut the estate’s vegetable cropping from a five-year average of 1,000 acres to 840 acres. With a second year of drought starting to impact, he said that the 40mm of rainfall last month has kept cereal crops growing. Although the estate’s soil moisture deficit was 10mm, it was very dry at depth.

He said that the Environment Agency had been very helpful in making as much water as possible available and had extended the “winter storage” pumping period by a month to April 30. As a result, the estate’s reservoir was at 70% of capacity – a month ago, it was half-full.

He has drilled his key cereal crops earlier to ensure that autumn-sown wheat and barley developed a good root structure to withstand drought.

On the light soils on the Euston estate, moisture dictated cropping. And sugar beet crops have to be drilled with nurse crops to reduce sand blow.

Oilseed rape, which did amazingly well at almost two tonnes an acre, was established with a sub-soiler. They re-drilled about 60 acres of rape because in the third week of September, the conventionally ploughed and drilled area had been blown away.

On the southern end, the soil has a reasonable clay content and supports a cereal:sugar beet rotation on about 1,000 acres and through the river valley, there is an extensive higher level stewardship scheme on about 1,700 acres of grassland.

The irrigated cropping includes 500 acres of potatoes, 300 acres of onions and a small area of carrots. In the past five years, parsnips and carrots have been over-wintered. “We’ve got about 50 or 60 acres of over-wintered parsnips waiting to be lifted, which were strawed down in November. It is beautiful soil for growing root crops but it is no good without the water,” said Mr Blenkiron.

In 2011, a total of 320mm of rainfall was recorded and between February 28 and June 19, there was just 25mm. As the drought has continued, there has only been about 65mm of rainfall by the end of March. They could pump from the Little Ouse but could only three days last winter because of low flows. However they were taking 200 litres per second from the River Blackbourn, instead of the full 850l rate, for the reservoir, he said.

Instead of drilling wheat after beet, it has been decided to grow 280 acres of forage maize for a nearby biogas plant.

Another aim is to improve the soil structure and profile, so the in-hand element of the 10,500-acre estate, which includes 2,000 acres of woodland, has been soil mapped. “We’re importing about 7,000 or 8,000 tonnes of poultry manure as well as lot of cattle manure and chopping straw to try to put something back into it as well. That’s our plan of attack.”

Mr Blenkiron regretted the lack of incentives to invest in irrigation and water storage, noting that the 4% annual capital allowance had been ended. Last month, farmers’ leader Peter Kendall, who met fellow members of the Sapiston abstractors’ group, had written to the Chancellor, George Osborne, to make the case for long-term investment.