Serpentine and dunite as magnesium fertiliser

Abstract

The uptake of magnesium by plants from the use of the magnesium silicates serpentine and dunite was compared with that from dolomite and talc-magnesite, the latter two minerals being commonly used magnesium fertilisers in Nelson. Tobacco plants, white clover, and perennial ryegrass were grown in pots filled with sawdust. Plant nutrients were supplied in solution, except magnesium, which was applied at different rates of ground fertiliser. Field trials with tobacco and pasture are also described. When the four magnesium fertilisers were compared on an equal weight basis, dunite proved to be the most efficient; serpentine was equal to dolomite in certain cases but superior in the pot trials with tobacco and clover. Talc-magnesite gave variable results. Solubility Itests with water and dilute acids showed that the magnesium silicates serpentine and dunite are readily broken down, releasing magnesium. © Taylor & Francis Group, LLC.