Madison, Wisconsin
September 29, 2008
The oldest continuous cotton
production experiment shows that winter legumes are as effective
as nitrogen fertilizer in producing non-irrigated, 10-yr average
cotton yields.
A plot of land on the campus of Auburn University shows that 110
years of sustainable farming practices can produce similar
cotton crops to those using other methods.
In 1896, Professor J.F. Duggar at the Agricultural and
Mechanical College of Alabama (now Auburn University) started an
experiment to test his theories that sustainable cotton
production was possible on Alabama soils if growers would use
crop rotation and include winter legumes (clovers and/or vetch)
to protect the soil from winter erosion.
Today, his experiment on the campus of Auburn University is the
oldest, continuous cotton experiment in the world and the third
oldest field crop experiment in the United States on the same
site. The experiment, known as “the Old Rotation,” has continued
with only slight modifications in treatments and was placed on
the National Register of Historical Places in 1988.
Researchers at Auburn University and at USDA-Soil Dynamics
Laboratory in Auburn, AL, have prepared the first ever
comprehensive research publication covering the entire 110-yr
history of this experiment. It was published in the
September-October issue of Agronomy Journal, and provides
insight into issues both past and present that effect
sustainable crop production in the South.
The thirteen plots in the Old Rotation include (i) continuous
cotton, (ii) a 2-yr rotation of cotton with corn, and (iii) a
3-year rotation of cotton-corn-wheat-soybean. These crop
rotations include treatments with and without winter legumes
(usually crimson clover and/or vetch) and with and without
fertilizer nitrogen.
After more than 110 years, the Old Rotation continues to
document the long-term effects of crop rotation and winter
legumes on cotton production in the Deep South. It provides
growers, students, and faculty with a living demonstration of
fundamental agronomic practices that result in sustainable crop
production. Long-term yields indicate that winter legumes are as
effective as nitrogen fertilizer in producing non-irrigated,
10-yr average cotton yields of 1,100 pounds lint per acre.
Winter legumes and crop rotations contribute to increased soil
organic matter. Higher soil organic matter results in higher
crop yields.
In 1997, the Old Rotation entered a new era of agricultural
production where boll weevil eradication, genetically modified
crops, and conservation tillage almost eliminated the need for
the plow and pesticides. In 2003, irrigation was added to half
of each plot. Yields of cotton, corn, wheat and soybean continue
to increase far beyond the yields of Professor Duggar’s
generation. Since initiating conservation tillage practices in
1997, all-time, non-irrigated record yields have been made on
all the crops grown on the Old Rotation: 1,710 pounds cotton
lint per acre in 2006, 95 bushels wheat per acre in 2001, 236
bushels corn per acre in 1999, and 67 bushels of double-cropped
soybean per acre in 1997 after wheat.
The full article is available for no charge for 30 days
following the date of this summary. View the abstract at
http://agron.scijournals.org/cgi/content/abstract/100/5/1493.
A peer-reviewed international journal of agriculture and
natural resource sciences, Agronomy Journal is published six
times a year by the American Society of Agronomy, with articles
relating to original research in soil science, crop science,
agroclimatology and agronomic modeling, production agriculture,
and software. For more information visit:
http://agron.scijournals.org.
The American Society of
Agronomy (ASA), is a scientific society helping its 8,000+
members advance the disciplines and practices of agronomy by
supporting professional growth and science policy initiatives,
and by providing quality, research-based publications and a
variety of member services. |
|
