Soil compaction is a major limiting
factor in restoring native vegetation on reclaimed surface mined land in the
Appalachian coal mining region of the eastern USA. It limits available water
and nutrients, reduces pore volume, restricts root elongation and development,
reduces plant growth, and leads to anaerobic conditions that many plants are
unable to tolerate.
Previously,
non-native forage species such as tall fescue (Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.) have been
planted because they easily established on reclaimed mine soil. And some
studies have shown that establishing large-statured, robust prairie species as
an alternative to low-diversity forage complexes might improve soil conditions
on reclaimed mine land over time.
In this study, the
authors conducted a 10-week glasshouse study comparing growth of “Pete” eastern
gamagrass
(Tripsacum dactyloides L.), “Bison”
big bluestem (Andropogon gerardii Vitman),
and “Jesup MaxQ” tall fescue at soil bulk densities (BD) of 1.0, 1.3, and 1.5
g·cm-3. They also examined effects of arbuscular-mycorrhizal fungi
(AMF) on plant growth in relation to compaction. Sources of AMF were a
reclaimed surface coal mine soil and a native tall grass prairie soil.
The results
indicated that shoot and root biomass of tall fescue and big bluestem were
reduced at 1.5 BD while eastern gamagrass growth was not affected. Growth of big
bluestem and eastern gamagrass was greater with AMF than without, but similar
between AMF sources. Tall fescue growth was not enhanced by AMF. Overall, tall
fescue biomass was 3 times greater than eastern gamagrass and 6 times greater
than big bluestem when comparing only AMF-colonized grasses. Eastern gamagrass
and big bluestem were both slower to establish than tall fescue. Eastern
gamagrass appeared to be more tolerant of compaction, while big bluestem appeared
somewhat less tolerant.
In conclusion, the
AMF associated with cool-season forage grasses on reclaimed mine soil in this
study is suitable for establishment of warm-season AMF dependent prairie
grasses like big bluestem and eastern gamagrass. And successful establishment
of warm-season prairie grasses on compacted reclaimed mine soil will require
effective AMF and considerably more time than cool season grasses such as tall
fescue, but could useful in increasing biological diversity.
Article by Mark
Thorne, et al, from The Ohio State University, Columbus, USA.
Full access: http://mrw.so/4py3FG
Image by Bill Harms, from Flickr-cc.
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