20th December 2006 - TARMAC STUDY PROVES BENEFITS OF 'GREEN FERTILISER'

Green fertiliser, or AgSlag as it's commonly known, which is made from steel slag dust, now has proven benefits for arable and grassland farming, according to Tarmac and Newcastle University.

Steel slag dust is a by-product of the steel manufacturing industry, which currently produces around half a million tonnes of it each year. In a bid to reduce the amount of steel slag dust being sent to landfill, a joint research study led by Tarmac and Newcastle University has been carried out to measure the benefits of using 'green fertiliser' and to demonstrate its long-lasting effects.

Field trials in Scotland have also shown that AgSlag is capable of boosting grass growth; restoring the natural pH balance and mineral content of the land; increasing crop yield and improving the well-being of livestock. Importantly, the product also has a lasting effect and in most cases land only requires treatment every three to five years.

Dr Howard Robinson, head of product development at Tarmac, said:
"Our field trials in Scotland have proven that AgSlag rejuvenates grassland and benefits grazing stock by producing thicker, lush pastures. The treatment can also help to prevent disease in the vegetation and encourage the growth of a more diverse range of grass and plant species."

Dave Merrilees, senior soil and water management specialist at the Scottish Agricultural Association, comments: "The field trials carried out on the benefits of AgSlag in grass production showed that a similar grass yield can be achieved by a single application of AgSlag, compared with separate applications of ground or magnesium limestone and triple-super-phosphate.

"Application of AgSlag to an acid soil with 'low' Phosphorus (P) status resulted in a pH increase from 4.9-5.6 within seven weeks of application and an increase in soil P status to 'moderate' showing a significant net gain in plant P uptake. AgSlag also increased plant uptake of magnesium reducing the risk of hypomagnasaemia in livestock."

Commenting on the long-lasting effect of the product, Howard Robinson adds: "AgSlag acts as a slow release mechanism for soil-locked phosphates, keeping the soil replenished for, on average, three to five years; about two years longer than conventional soil treatments."

Green fertilisers, such as AgSlag, have been used in Britain for many decades, but are only now becoming more widely used as farmers look for more sustainable solutions that bring benefits for the land, crops and livestock.

Howard Robinson concludes: "Farmers are looking for green alternatives that enrich rather than deplete the environment. AgSlag is free from nitrates and harmful leachates, there have even been some reports that animals that graze on treated pastures have higher fertility rates and that weight and stocking levels have also increased."

For more information about AgSlag, contact Tarmac on 01609 771132.