March 14, 2013
Drainage Benefits can come Quickly
At £2000-2500/ha, field drainage is expensive, admitted Warwickshire contractor and Nuffield Scholar Rob Burtonshaw at the Agrii-sponsored Soil and Water Management Centre’s latest workshop . But the investment could be recouped sooner than some growers believe.
“Drainage allows you to get onto the land when you want rather than when the water dictates. But the main point is that it increases yields.”
Trials by the Field Drainage Experimental Unit, for instance, show that it boosted winter wheat output by 22.5%, and a Canadian insurance scheme running from 1979-1999 put the figure at 38%.
Even at the lower figure it would take only six years, with wheat at £200/t, to recoup a £2250 outlay where the crop initially yielded only 8t/ha, Mr Burtonshaw calculated. Given an expected life of 30 years, the annual cost was only £60-70/ha.
“Drainage is something the industry has forgotten about – it’s fallen down the priority scale. It’s been largely a case of ‘out of sight out of mind’. And as contractors we’ve failed to talk enough about its benefits.”
Ditching by contractor could be done for as little as £300/day plus transport costs, he added.
The heyday of UK land drainage was in Victorian times, when the equivalent of £12 billion was spent on it between 1850 and 1880. Even after the Second World War 2m hectares were drained through grant-aided schemes. But after the withdrawal of grants in the mid-1980s the area drained each year dropped dramatically.
In 1987 ADAS estimated that 20% of agricultural land in south-east England could be relying on 19th century schemes, and in the north the figure was thought to be as much 70%. At the same time it was suggested that 50,000 ha a year were ceasing to function.
“A large percentage of that was because schemes weren’t being maintained, and today we’re nowhere near putting in 50,000 ha a year,” said Rob Burtonshaw. “My educated guess is that it is under 10,000ha.”
Since then farmers had tended to call on drainage contractors to deal with relatively small areas and often only in emergencies, noted Mr Burtonshaw. “But our experience is that when people have some drainage done they usually want more.”
By kind permission of Farmers Weekly.