Magnesium mania risky

Waimarino Bulletin, Volume 3, Issue 16, 10 September 1985, Page 17

Magnesium mania risky

Some farmers have given way to "magnesium madness'Mn their attempts to control grass staggers in cattle by oral drenching, says a Massey University soil scientist. Dr Max Turner says arguments pointing to magnesium deficiency were dismissed not so long ago. "Now we have this wholesale magnesium mania where few seem to believe the problem can be controlled in any other way except oral supplementation," he says. Over the years Dr Turner has suggested magnesium fertilisers could have a role, but the idea has met stiff opposition. While it was accepted that magnesium fertilisers might produce gains, this approach was considered too expensive compared to drenching. But Dr Turner says drenching has risks. Guidelines on timing are not clear and general recommendations on rates can't cover all farm

situations and individual animal requirements. As a result, the rates used by farmers are sometimes close to toxic levels. Dr Turner has just been awarded a research grant to investigate the potential of magnesium fertilisers. He plans long-term trials of up to five years to find out

the effectiveness of regular annual applications of dolomite. He is using dolomite because it is a New Zealand source of magnesium, it is slower acting and expected to last longer, it supplies both calcium and magnesium, and it has a strong liming action.