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Livestock Grazing Effects on Reclaimed Grasslands
1989
1998
Mercer and Oliver
North Dakota
Center and Beulah |
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| Cattle
grazing a mixed grass reclaimed area on the Freedom Mine |
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Project Partners: North Dakota State University, North Dakota
Lignite Energy Council, and the North Dakota Industrial Commission.
Reasons for Action: Re-establishment of diverse and seasonally
balanced grassland plant communities following surface coal mining
in the Northern Great Plains is difficult to achieve due to the
competitiveness of cool season grass species.
Objectives: Evaluate early season livestock grazing effects
on plant species diversity and seasonality of established reclaimed
grasslands (5-10 years after re-establishment).
History of Site: The research was conducted on the BNI,
Freedom and Indian Head coal mines in Mercer and Oliver Counties
of west central North Dakota. The mines lie within an area used
primarily for agriculture. Grasses and grass-like plants dominate
the principal vegetative community of mixed grass prairie. The study
grasslands were reclaimed between 1983 and 1989 and grazing began
four to eight years after seeding. Grazing was conducted mid to
late May through early to mid July each year to decrease the competitiveness
of cool season grass species.
Design Narrative: Five transects were established on soils
that were considered silty site types at each mine. Basal cover
and species composition were estimated each year using the ten-pin
point-frame method. Ten frame (100 points) readings were taken randomly
at each sampling location (10 per transect) along transects. Alpha
diversity was estimated using this cover data.
Construction Narrative: At the BNI Mine a 65-hectare pasture
was seeded in May 1983, and 1984. Grazing was implemented in the
fall of 1992 at 1.39 animal unit months per ha (AUM/ha). Thereafter
the pasture was grazed in the springs of 1994 to 1998 at an average
stacking rate of 1.46 AUM/ha. A 32.4 hectare reclaimed area on the
Freedom Mine was seeded and fertilized in the fall of 1989. Grazing
was implemented in April 1993. Each year (1994-1998) grazing began
in mid-May and terminated the beginning of July. Stocking rate averaged
2.97 AUM/ha over the five years of grazing. A 26.7 hectare reclaimed
area was seeded, mulched and crimped in 1986 and hayed in 1987 on
the Indian Head Mine. Grazing was implemented in 1994 and continued
annually through 1998 with an annual stocking rate of 0.74 to 0.84
AUM/ha. Grazing began each year in mid-May and continued to late
July.
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| Reclaimed
grasslands were seeded with six to seven native grass species,
mulched and crimped |
Was this project successful? Yes.
How was success determined? Early season grazing increased
the basal cover of warm season grasses at all three mines during
the study. Basal cover of introduced cool season grasses declined
at two mines while remaining similar at the third. At the species
level, the warm season grasses, Bouteloua curtipendula and B. gracilis
increased at three and two mines, respectively. Stipa viridula,
a desirable cool season grass species, decreased at all three mines.
This plant species may need to be monitored closely under early
season grazing to be maintained at an acceptable level in grazed
stands.
Supplementary Narrative: Seasonal balance of warm and cool
season grass species and alpha diversity of the reclaimed grasslands
improved on all three mines following initiation of grazing. Warm
season grass species basal cover increased to comprise >50% of
the cover on the reclaimed grasslands by the end of the study. This
positive trend in warm season grass cover occurred during an unusually
wet climatic cycle during the growing season, which tends to favor
cool season grass dominance. Introduced cool season grasses decreased
with early season grazing.
Management of diverse grasslands following re-establishment should
be aggressive and initiated soon after stand establishment. Grazing
to improve species composition should commence 2-3 years after seeding
reclaimed grasslands to prevent cool-season grass species from becoming
dominant. In addition, grazing cool-season species early in the
spring of the year on reclaimed grasslands and removing animals
from pastures by July 1 should also improve the competitiveness
of warm season grass species.
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| Despite
drastic disturbance of surface coal mining operations, grassland
can be reclaimed to productive agricultural use in only a few
years |
For more information on this project, contact:
Don Kirby
North Dakota State University
Department of Animal and Range Sciences
Hultz Hall
Fargo, N.D. 58105
Phone: (701) 231-8386
E-mail: dkirby@ndsuext.nodak.edu
Available Documentation: Proceedings - 2000 Billings Land Reclamation
Symposium;
Cline, Thomas, M.S. Thesis. 1999. Species Composition Trends Following
Grazing of Reclaimed Grasslands.
Submitted by: Don Kirby
Date: September 22, 2000
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