Seasonal trends in water table level and soil moisture
for four plant community types within an irrigated eastern
Oregon riparian zone were described. Aboveground biomass,
species composition, litter, percent bareground and percent
basal cover of key plant species and life forms were measured.
The relationship between water table levels and soil moisture
content were analyzed using simple linear regression.
Transition zones between plant community types based on soil
moisture and/or depth to water table during the growing season
were determined. The soil moisture-water table relationship
can be used to predict changes in plant community composition
induced by a permanent depth to water table change.
Irrigation impact on meadow water table levels and stream
temperature were determined. Water table levels responded to
irrigation manipulations within days. The permanent cessation
of irrigation would shrink the riparian meadows contained
within this study from widths in excess of 300 m to less than
60 m.
Continuous stream temperature data were collected on a
stream running through adjacent non-irrigated and irrigated
meadows. Daily maximum stream temperatures in the segment
contained within the irrigated meadow were 1.0�� to 3.0�� C
cooler than the reach contained within the non-irrigated
meadow.
Management impact on plant community attributes, forage
production and forage quality were assessed under three
pasture management alternatives. Comparison of stubble
height, litter, forage production, forage quality, species
composition, percent bareground and percent basal cover of key
plant species and life forms indicated all three management
alternatives are sustainable from both a plant community and
a livestock production perspective. / Graduation date: 1996
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/34591 |
| Date | 24 April 1996 |
| Creators | Stringham, Tamzen K. |
| Contributors | Krueger, William C. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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