Put fears aside and use compost from recycled waste, farmers told

Published on Friday 13 August 2010 18:00

Increasing the amount of domestic waste that is being recycled has produced a problem for local authorities, with farmers apparently reluctant to use it for fertiliser.

"The problem is getting farmers to take the compost. The site I look after is now generating more than 5,000 tonnes annually. We send it out to allotments but we could do with more farmers taking it," said Peter Goldie of Dundee City Council's waste management team.

Speaking at the Potatoes in Practice event on the outskirts of Dundee, Will McManus from Zero Waste Scotland said there were now about three million tonnes of compost being generated in the UK every year.

This is ten times the figure of a decade ago, and he said the amount of waste being recycled into this type of fertiliser was still rising rapidly as local authorities sought to cut the amount of material going into landfill.

The local authority site in Dundee is one of about 20 such recycling units throughout Scotland, and McManus estimated that 60 per cent of the end product went onto agricultural land.

He accepted that there were concerns by some farmers over the potential to introduce organisms such as Potato Cyst Nematode onto the farm but said that the maturing process and the requirements laid down in BSI PAS100 were sufficient to prevent any such problems.

Growers with concerns should just go for "green waste" compost, which is made mostly from garden material compared with "food waste" where there might be potato peelings.

In fact, McManus said some research had shown that the end product contained organisms that could "out-compete" any nematodes in the soil, so it could actually be used to clean up fields infested with PCN.

"Compost is a very safe fertiliser with very few potential toxic elements," he said

While it is classified as a fertiliser, McManus said the main benefit came from its ability to improve soil structure - because it contained twice as much lignin as farmyard manure. The improved soil structure brought other benefits such as increasing the water capacity, leaving more moisture available for crops.

Although there has not been a great deal of scientific work on the qualities of composting carried out, some experiments had shown that a long-term increase in yield of between 5 and 10 per cent could be achieved.

McManus advised farmers to consider using it to substitute a percentage of their fertiliser needs. It is a very cost effective compound, costing far less than artificial fertiliser. The potash in the compost is more available to plants than in artificial fertiliser, he added. With prices for artificial fertiliser once again back on the increase, compost was a good buy, he reckoned.