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A new use for gypsum-containing byproducts from coal-burning electric
power plants could make acidic soils more productive. In an ARS
greenhouse study, corn grew two to three times better when gypsum
byproducts were added to acid soil. The gypsum provides calcium, reducing
the effects of soil acidity and aluminum toxicity commonly found in acid
soils. Scientists tested 16 byproducts from coal-burning power plants and
found three high-gypsum byproducts that hold promise as inexpensive
materials for use on farmland. All were safe to use when mixed in soils
at appropriate levels. At optimum levels, all three byproducts not only
increased root length but also grew plants with the fine, extensive,
highly branched roots that mark a healthy plant. Plants grown on highly
acid soils normally produce short, stubby roots.
Appalachian Soil and Water
Conservation Research Laboratory, Beckley, WV
Ralph B. Clark, (304) 252-6426, extension 2854
Photographing the tiny spaces where soil microbes live provides
scientists with a powerful new tool for determining a soil's health.
Researchers take a picture of a soil sliver, encased in a resin coating,
then scan the photo by computer to determine the shape of soil pores.
These tiny openings hold water and provide a home for microbes that keep
soil healthy. Scientists use a new kind of mathematics, called fractal
geometry, to examine the roughness of the pore surfaces to determine soil
quality, as part of a long-term study of organic versus conventional
farming at the Rodale Research Center in Emmaus, PA. ARS scientists
believe there is an ideal soil pore roughness that provides just the right
amount of room for water and the beneficial microbes. So far, they've
found that fields where legumes are grown as green manure had better pore
roughness than fields receiving manure or fertilizer.
Soil-Microbial Systems Laboratory, Beltsville, MD
Larry J. Sikora, (301) 504-9384
Systems Research
Laboratory, Beltsville, MD
Yakov Pachepsky, (301) 504-5872
Microwave radiation produced by soil and measured by satellites could
one day tell farmers how much moisture has been lost in their fields.
As a possible model for satellite use, NASA and ARS scientists are testing
two large antennae on a boom raised 80 feet above a farm field. The
antennae measure soil moisture changes over the entire field by recording
natural microwave emissions from the soil 24 hours a day. The more water
present, the lower the emissions from the surface. Researchers connected
the antennae to sensors tuned to the microwave frequencies best suited for
measuring water at depths of one to two inches. Scientists then correlate
these to soil moisture conditions deeper in the soil. Measurements have
been recorded in Beltsville, MD, since 1983, and began in Davis, CA, last
summer. Satellite measurements were most accurate around 6 a.m. and 6
p.m., representing two moisture extremes.
Hydrology Laboratory,
Beltsville, MD
Thomas J. Jackson, (301) 504-8511
Cover crops planted under trees in orchards reduce soil erosion and
protect the groundwater. The cover crops' roots continually die and
regenerate, providing a carbon-based food supply for soil microorganisms
that help break down pesticides before they reach groundwater. Ground
covers also use some of the available soil nutrients, limiting a young
tree's excess growth of shoots and leaves and reducing the need for
pruning. Excessive vegetative growth can reduce fruit yield by shading
the lower part of the tree, decreasing the tree's total number of
blooms.
Appalachian Fruit Research
Station, Kearneysville, WV
D. Michael Glenn, (304) 725-3451
Last updated: October 28, 1996
Return to: Quarterly Report
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