NEWS HIGHLIGHT
Pelletized manure
reduces runoff
There
is a considerable amount of uncertainty concerning the environmental impacts that
animal hormones have on surface water. However, a study from the University of
Delaware that examined estrogen concentrations in runoff from agricultural fields
fertilized with chicken manure found that it is as much about the application
of the manure as it is about the measurement of the types of estrogen.
November 22, 2010 – There
is considerable amount of uncertainty concerning the environmental impacts that
animal hormones have on surface water. However, a study from the University of
Delaware that examined estrogen concentrations runoff from agricultural fields
fertilized with chicken manure found that it is as much about the application
of the manure as it is about the measurement of the types of estrogen.
|
|
The study was conducted on
the experimental plots on the Coastal Plain agricultural soils in Middletown,
DE. It measured and compared the amounts of both toxic, free forms of estrogen
hormones and less toxic species found in runoff. Corn was planted as a cover
crop and chicken manure was applied in either a pelletized form or a raw litter
form. Reduced tillage and no tillage treatments were also employed. Samples of
surface runoff were collected after 10 rainstorms during the 2008 summer
growing season from April through July.
Sudarshan Dutta, the
author of the study, found that the amounts of estrogen were lower in plots
fertilized with pelletized manure and plots that received no-tillage
treatments.
Additionally, Dutta
discovered the entire range of estrogen concentrations in the samples was
significantly lower than those observed in other previous agricultural studies.
Nevertheless, concentrations of the less toxic conjugate forms of estrogen were
higher than the toxic, free forms.
According to Dutta, prior
studies did not usually measure the conjugate forms of estrogen, saying it is
necessary to measure these forms.
“The higher concentration
of conjugate forms of estrogens underscores the need for reporting all forms of
the hormones. This is especially critical considering that conjugate species
can be converted to the toxic free forms under certain environmental
conditions,” he says.
The study was partly
funded through a grant by the United States Department of Agriculture and the
results are published in the September-October 2010 issue of the Journal of
Environmental Quality.
View the abstract at
www.agronomy.org/publications/jeq/abstracts/39/5/1688.
