Features Applications Other
Tracking phosphorus runoff from livestock manure

June 15, 2010, Madison, WI
– Nutrient runoff from livestock manure is a common source of agricultural
pollution. Looking for an uncommon solution, a team of scientists has developed
an application of rare earth elements to control and track runoff phosphorus
from soils receiving livestock manure.


June 15, 2010, Madison, WI
– Nutrient runoff from livestock manure is a common source of agricultural
pollution. Looking for an uncommon solution, a team of scientists has developed
an application of rare earth elements to control and track runoff phosphorus
from soils receiving livestock manure.

In addition to reducing
the solubility of phosphorus, this method shows particular promise for
researchers interested in tracking the fate of manure nutrients in agricultural
settings.

Led by Anthony Buda, a
team of scientists from the USDA Agricultural Research Service and the Chinese
Academy of Sciences applied two rare earth chlorides (lanthanum chloride and
ytterbium chloride) to poultry, dairy, and swine manures. The goals were to
evaluate the effects of rare earth elements on phosphorus solubility in manures
and to describe the fate of phosphorus and rare earth elements in surface
runoff when manures were surface-applied to packed soil boxes and subjected to
simulated rainfall.

The study was reported in
the May/June 2010 edition of the Journal of Environmental Quality, published by
the American Society of Agronomy, the Crop Science Society of America, and the
Soil Science Society of America.

Common uses for rare earth
elements include industry, technology, and agricultural production, but there
is a growing trend for using them in environmental research, particularly to
label and track soil erosion and sedimentation during storm events on
agricultural and rangeland watersheds.

The results of the study
showed that rare earth elements had a remarkable ability to reduce soluble
phosphorus in livestock manures. In particular, adding lanthanum resulted in
maximum reductions of water extractable phosphorus from dairy and poultry
manures.

While these soluble
phosphorus reductions were comparable to using other chemical treatments such
as alum and lime, widespread use of rare earth elements in this manner would
likely be cost prohibitive.

According to the authors
of the study, the real potential benefit of rare earth elements lies in their
ability to label phosphorus in livestock manures, a boon for researchers. Their
rainfall simulation experiment clearly showed that rare earth elements
precipitated greater than 50 percent of the dissolved phosphorus in runoff. The
results revealed that rare earth elements can be used to track the fate of
phosphorus and other manure constituents from soils treated with manures.

This study introduces rare
earth elements as a potentially valuable new tool for research in agricultural
phosphorus management. Extending this technique to field, landscape, and small
watershed scales will contribute to testing and validating phosphorus
management strategies, including critical source area management. Agriculture,
particularly the dairy, poultry and swine industries, stand to benefit from
improved nutrient containment of their manure-treated soils.

The abstract can be viewed
at http://jeq.scijournals.org/cgi/content/abstract/39/3/1028.