We are urgently developing research requirements with other European laboratories to make sure we understand and the disease (Schmallenberg) better.Reducing farming's water footprint
'Pumping money down the pipeline' was the theme of the UK Irrigation Association’s spring seminar. Teresa Rush reports on some of cutting the impact of spiralling irrigation energy costs.
CARBON footprinting has become a familiar phrase, now industry and consumers are being asked to consider the ‘water footprint’ of goods and services.
Scientists and environmentalists define water footprint as the total volume of freshwater used to produce goods and services, measured in cubic metres.
However, a water large water footprint is not necessarily bad, unlike its carbon counterpart.
Speaking at the UKIA conference, Tim Hess of Cranfield University, outlined the amount of water required to produce 1kg of a range of agricultural products.
Sheep meat production, for example, requires 6,000 litres of water/kg of production, beef 15,500 and poultry 4,000. To produce 1kg of wheat requires 1,300 litres of water and 1kg of maize, 900.
Analysis of UK crops reveals the growing stage is likely to have the largest impact on its water footprint.
Potatoes use 130 litres of water/kg during growth, 10 litres/kg during processing and 0.1 litres/kg during preparation by the final consumer.
Britain’s agricultural water footprint equates to 30 per cent of annual rainfall or 3,400 litres/person/day and 62 per cent comes via imports from overseas, said Dr Hess.
Crop production accounts for 60 per cent of the agricultural water footprint and livestock production 40 per cent.
Water footprints are coded as green for water used at the point where rain falls; blue where water is abstracted from rivers, lakes and groundwaters and grey for water required to dilute polluted return flows. While blue or irrigation water is taken from renewable resources, there is also competition for this water.
The UK food industry uses around 500 million cu.m of blue water a year, of which 23 per cent is used in livestock production, 27 per cent for irrigation and 50 per cent in the industry.
“Not all abstraction is harmful. It includes water that would have no other use and water in excess of other requirements, such as high winter flows,” said Dr Hess.
However, in water-stressed catchments, abstraction may have severe environmental impacts. Potatoes grown in Cornwall or Pembrokeshire, for example, may have a lower water footprint than crops grown in Norfolk or Suffolk.
There are ways of reducing the water footprint of a production system: production and abstraction can be moved to less stressed catchments, facilitated perhaps by the ‘clawback’ of irrigation licences; high flow or rain water can be stored and more efficient use of water can be made on farms with better equipment or irrigation scheduling.
Dr Hess said there are limited opportunities to reduce the water footprint of livestock production as most water is used for drinking.
Livestock enterprises are also concentrated on the western side of the country, where there are fewer stressed catchments.
At the processing and retail level, water footprints could be reduced through improving water use efficiency by recycling and reducing waste levels. “Food waste is water waste,” said Dr Hess.
Source:
Arable
