1 September 2000

Dutch irrigator good for environment and profits

By Nigel Chapman

A PIONEERING irrigation system – the first of its kind in the UK – is undergoing tests in Lincolnshire.

Lansen Nursery in Spalding is home to the new system built by Dutch company Brinkman. Its simplicity and ecological benefits prompts the question why it has not been developed before.

The nursery has done away with traditional sprinklers for the 1.5m outdoor herbaceous pot plants it produces each year in favour of a complete water and feed system.

A key feature is that it reuses the water and fertiliser solution which nursery owner Jan Lansen says saves up to 60% of the water which was once lost.

A membrane has been laid on toughened polystyrene all around the five acres of growing area which prevents the solution seeping into the ground.

Each 25 x 10m section is served by four pump outlets which flood the area on the instructions of a computer program.

The system supplies exactly the same amount of solution to each pot plant, promoting better uniformity, an important factor for the retail sector. When the watering is complete – and it is fast, delivering 72,000 litres in just six minutes – the system shuts off and the outlets become drains.

A slight incline in the beds encourages the unused solution to drain away and be pumped back into one of two massive storage tanks.

Each 150cu m tank stores a separate solution which, at the touch of a button, can be strengthened by adding more fertiliser or, if required, diluted with water supplied from a third storage tank.

"The sprinklers used to be on for an hour each day, but we only use this system, on average, twice every 10 days," says Mr Lansen. "It supplies enough water in six minutes to last the plants about five days."

There are obvious environmental and financial gains in reusing water and preventing fertiliser seeping in the ground.

"It took about four weeks from mid-May to install and, while we have had some teething problems, it has been pretty smooth for us," he says.

Mr Lansen adds that he has had to learn how to grow products in a totally different way, but considers that it all appears to be going very well so far.

"We are a little coy in saying how much the system cost, but I would expect for it to have paid for itself within five or six years."

A similar unit has operated indoors but the stumbling block outdoor was the danger of frost. The solution was to use air to blow the valves dry once the solution has been pumped back into the storage tanks.

"With the possibility of environmental laws in two years that insist fertlisers are not washed into the ground, we believe we have the system of the future," says Mr Lansen. &#42