Measuring calcium in serpentine soils

Serpentine
soils contain highly variable amounts of calcium, making them marginal
lands for farming. Successful management of serpentine soils requires
accurate measurement of the calcium they hold. Research published this
month in the Soil Science Society of America Journal shows that
multiple measurement techniques are needed to accurately measure
calcium content in serpentine soils, according to eurekalert press
release.

To make these marginal growing lands
productive, farmers must apply fertilizers to make up for missing
nutrients like calcium. Over- and under-application of nutrients can
both be harmful to the land and its crop yield. Accurate measurement of
the available calcium in serpentine soils is vital to determining the
fertilizer needed.

Serpentine soils are formed primarily
from serpentinite rocks. These rocks are formed from pieces of the
earth's mantle through a metamorphic process involving heat and water.
Serpentine soils can be found throughout northern California.

Scientists at University of California,
Davis tested five techniques for measuring calcium in serpentine soils:
X-ray diffraction, electron microscopy, polarized and plane light
petrographic microscopy, and elemental analysis of the whole rock.
Researchers found that a combination of all these techniques was
necessary to accurately identify and measure the calcium in
serpentinite rocks.

Researcher Donald McGahan said "The
non-serpentinite rock bodies included in the serpentinite landscape
and, to a lesser extent, calcium-bearing accessory minerals in the
serpentinite rock have the potential to act as a landscape fertilizer."