This research was conducted on three study areas on elk winter
ranges in Northeast Oregon. One was on the Starkey Experimental
Forest and Range and the others were in the same vicinity. Plant
appendages, spring and fall defoliation and fall growth of bluebunch
wheatgrass were evaluated in terms of quality of nutrient content
during September through April of 1986-87 and 1987-88. Four
treatments were applied. Plants were clipped to a 2.5 cm and 7.6 cm
stubble height in the spring before the boot stage of phenological
development; plants were clipped to a 7.6 cm stubble height in the
fall after plant maturity in September; plants were not clipped
during the year. Percent crude protein, dry matter digestibility
(DMD), acid detergent fiber (ADF), and lignin were evaluated
monthly. Samples from the four treatments were also analyzed from
October to April to determine monthly changes in nutrient contents.
Production of growth from all treatments was measured in October and
March each year.
Leaf material had higher percent crude protein and DMD, with
lower percent ADF and lignin than the inflorescence and culm. The
third leaf (the youngest plant material) had the highest nutrient
value of all appendages. The culm and inflorescence values were not
statistically different.
Growth following spring defoliation treatments produced higher
percent crude protein and DMD (P<.05), with a lower percent ADF and
lignin than non-treated plants in both years. This was particularly
pronounced during 1986 when precipitation in late summer initiated
fall growth. Growth following spring defoliation and bluebunch
wheatgrass not defoliated did not produce crude protein or DMD
values sufficient to meet minimum dietary maintenance requirements
for elk.
Fall precipitation adequate to promote fall growth occurred
only in 1986. Growth after fall defoliation had the highest percent
crude protein and DMD with the lowest ADF and lignin values of all
vegetation sampled. However, without 3-5 cm of late summer/early
fall rains, fall growth does not occur. This happened in 1987.
When growth does occur in fall the quality of the growth exceeds the
minimum dietary maintenance requirements for elk.
Freezing and thawing of fall growth plant material had minimal
effect on forage quality. There were differences (P<.05) between
the monthly values for percent crude protein and ADF starting in
October and ending in April. However, the percent DMD and lignin
from October to April were not different (P<.05). / Graduation date: 1993
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/37642 |
| Date | 07 May 1993 |
| Creators | Bryant, Larry Duane |
| Contributors | Krueger, William C. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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