Comparison of Aglime, crushed limestone, G Lime and dolomite
Types of Lime
In WA the main forms of lime are the natural minerals limesand, coastal limestone and dolomite and a chemical byproduct G lime (commonly called burnt lime). Each product is briefly described below:
occurs north of Perth, formed from shells and coral particles; high in lime and very fine in its natural state.
formed from the limesand particles that have been cemented together over time; typically lower neutralising value and much coarser than limesand.
formed in inland lakes; tends to be variable with clay impurities; typically has a lower neutralising value, is less soluble and much coarser than limesand.
a byproduct of quicklime manufacture; contains varying amounts of hydrated lime and calcium carbonate; unstable as the hydrated lime readily reverts to calcium carbonate; typically has a similar neutralising value but contains more coarse particles than limesand.
Quality of Limes
Quality is measured by:
a) Neutralising value
b) Particle size
a) High NV (90-95%)
b) Fine particles (99%<0.6mm)
c) High solubility
Aglime (limesand) is the most effective liming material available in WA as it has:
University of Western Australia research showed limesand increased soil pH more than G lime and crushed limestone (Speechly 1996).
Note: Rates of lime used in this experiment were adjusted to compensate for differences in neutralising value. See prev research.
Limesand increased canola yields more than either G Lime or dolomite in a field trial harvested in 1997 by Chris Gazey (DAFWA).
Adjustments were made to the lime rates to compensate for the lower neutralising value of the dolomite (67%), Both G lime and limesand were applied at 1 and 2 t/ha while dolomite rates were higher - 1.5 and 3.0 t/ha.
The results clearly show that limesand was the superior liming material with dolomite being much less effective even when applied at higher rates.
In fact canola yield increase from 1 t/ha of limesand was more than the yield increase from 3t/ha of dolomite and the same as the yield increase from 2t/ha of G lime.
The high neutralising value, fineness and solubility of Aglime (limesand) makes it the most effective liming material available in WA.
Calcium & Magnesium Bonus
Aglime contains calcium (34%) and magnesium (1.7%) which can supplement low supplies in many soils. Every tonne/ha of Aglime provides around 340kg/ha of calcium and 17kg/ha of magnesium. Trials have proven calcium and magnesium levels increase in plants after applying Aglime. Aglime supplies a good balance of calcium and magnesium as well as being the most effective liming material available in Western Australia.
Chris Gazey (DAFWA)
Andrew Speechly (Student Dept of Soil Science and Plant Nutrition – UWA)