Suffer or buffer
Suffer or buffer
The hopes of a small Scottish community hang on a buffer strip scheme to control soil erosion. Tom Allen-Stevens reports.
HOW can we be sure that buffer strips are the environmental panacea theyre cracked up to be? FWAG officers love them, the Government wants to divert millions of growers area aid payments into them and hardly a week goes by without a conference or farm visit that discusses their benefits.
Now their environmental worth as a pollution preventer is being put to the test at Loch Leven near Kinross in Scotland.
As well as the farms in its catchment area, several towns and villages sit on Loch Leven and service its £1.5m a year tourist industry. The water also feeds three paper mills, a distillery and a power generating company downstream. All of these suffer from algal blooms generated by phosphate pollution in the loch, so the pressure is on to decrease the amount of phosphorous going into it. But phosphate pollution can come from a number of different sources, so why is the finger of blame pointed at local growers?
"Its a process of elimination, really," reasons Alec Taylor who heads up the local SAC team in Perth. "Roughly a third of the phosphate measured in 1985 was found to come from industry, another third from sewerage and a third from other sources. Clearing up industrial pollution was easy with new technology and is legally required anyway. Phosphate management systems halved phosphorous loadings from waste water treatment works by 1995 and have reduced it further since. The only other significant source is run-off from the burns feeding the loch."
The prime suspect here is soil erosion, so the Loch Leven Catchment Management Project has been set up to try to solve the problem. One of the projects aims is to encourage growers to establish buffer strips in fields abutting the burns that feed the loch. Katrina Castle, of SACs environmental division, who has been monitoring the projects progress, explains the theory: "most of the phosphorous movement occurs through phosphates attached to the soil particles, which is washed into the burns during a period of heavy rainfall. The classic way to prevent this is to put a buffer strip alongside the watercourse. The vegetation in the strip traps the soil particles."
Efforts have concentrated on a pilot scheme on the Pow/Greens burn, one of the main tributaries to the loch. The burns catchment area is only 10% of the lochs total, yet it contributes 30% of the total river-borne load of P to the loch. The soil on this side of the loch is rich and fertile and can support field-grown vegetables and potatoes as well as cereals. This means many fields next to the burn are traditionally left fallow over winter, and some are steeply banked towards the watercourse – increasing the chances of erosion, believes Dr Castle.
Although growers have reacted with varying degrees of enthusiasm, the burn is now thought to be the most extensively buffered watercourse in Scotland. "At least half of the burn is protected on both sides and all of it is protected on one side," points out Sandy Braid, who farms 800 acres of cereals, potatoes, vining peas and vegetables in the lower reaches of the burn on sandy loam soil.
Mr Braid has been actively involved with the plan, and has helped recruit other farmers. All of his burn-side fields are fringed with 10m buffer strips, for which he receives funding from the Countryside Premium Scheme (CPS). He is clear on his motivation for the plan: "weve got to be seen to be cleaner than clean, which is important for our business as well as our reputation in the local community. Were very proud of what were doing here."
Other farmers have received funding to construct river dykes to trap eroded soil or fencing to keep livestock away. But a lack of funding is one of the root causes for a general reluctance by others to take up the cause. "When youre looking at £240/ha for set-aside or £500/ha for CPS, you have to be fairly keen to go for it on land that can bring you £5,000/ha," Mr Braid points out.
Many growers have had problems even getting into the scheme: the Catchment Plan adds few extra points to a farms application to join CPS. Its only through accumulating points awarded for environmental assets worthy of grant-aiding that farms are likely to be successful when applying for funding for CPS. If being in the Catchment Plan is the only asset a farm has, it is likely to be rejected.
Recent research is also casting doubt over the effectiveness of margins next to watercourses. "Any soil erosion will be reduced through using buffer strips. What were not sure about is how much is moving through this route and how much is transferred through the soil itself," reports Dr Castle.
"On some sites, a buffer strip right next to the burn may not do all that much good. Rainwater may concentrate eroded soil into a hollow in the middle of a field. The buffer strip should go in the hollow in this case, but no farmer wants an uncultivated patch in the middle of his field."
Despite the downsides, she is confident that the pilot will be a success. "Its perfectly understandable why farmers are so reluctant to join, but it doesnt have to be all or nothing. Every little bit of margin helps to stop the phosphorous getting into the burn."
As yet there are no conclusive findings from the pilot scheme. The buffer strips have not been in place long enough to test conclusively, and any reduction of phosphorous into the loch will take years to have an overall effect.
The hope is that the scheme will reduce phosphate pollution out of the burn, supporting the role of buffer strips as a pollution preventer.
Loch Leven: battleground background
SCOTLANDS largest nutrient-rich loch, it has a surface area of 13.3sq km and a catchment area of about 145sq km. But this is only three-quarters of its original size: between 1828 and 1832 the loch was deepened to allow the railway to come through, ensure a regular supply of water to downstream mills and increase the land available for agriculture.
Its historical significance lends itself to tourism: in 1567 Mary Queen of Scots was imprisoned on the lochs central island. As a wildlife reserve it is highly protected and home to tens of thousands of migratory, wintering and breeding wildfowl. But for both the day-trippers and the ducks, the loch has one big turn-off: algal blooms, now caused mainly by agricultural activities in its catchment area.
Research during the 1970s showed that the algal blooms are down to eutrophication, or nutrient enrichment of the loch. If the weather conditions are right, the algae feeds off the phosphates in the water and multiply enormously, which can make local industries suffer. In 1992, the summer algal bloom cost the local shops, hotels and B&Bs an estimated £673,000 in lost business, but it is not just tourism that suffers: it cost the local fishery £110,000 and downstream industries incurred an extra £160,000 in increased production costs.