School of Agriculture and Land Resources Management, Agricultural and Forestry Experiment Station
Abstract
Forage trials of seeded perennial grasses were conducted at four sites
in three areas of southcentral Alaska on soils with pH readings generally
below 5.5 (down to 4 .35) . Three trials were at forested locations and
one at a subalpine site. Each trial was sustained for three to five harvest
years under a two-harvest system. 'Engmo' timothy (Phleum pratense) ,
the standard forage grass on strongly acidic soils in the region, equaled
or, more often , exceeded the other grasses in first-harvest yields, but
often was surpassed in second-harvest yields. Grasses often substantially
exceeding timothy in second-harvest yields included reed canarygrass
(Phalaris arundinacea) and entries of tufted hairgrass (Deschampsia
caespitosa) and Bering hairgrass (D. beringensis), sometimes providing
more total yield than timothy. Some red fescues (Festuca rubra) and
'Nugget' Kentucky bluegrass .(Poa pratensis) also tended to surpass
timothy in second growth. Smooth bromegrass (Bromus inermis) failed
at sites with soil pH below 5.3, but persisted at one site with pH varying
from 5.3 to 5.7. 'Garrison' creeping foxtail (Alopecurus arundinaceus)
also failed at these sites; its close relative meadow foxtail (A. pratensis),
was better adapted to the strongly acidic sites. Indigenous polargrass
(Arctagrostis latifolia) about equaled or surpassed timothy in yield at
two of the sites, and bluejoint reedgrass (Calamagrostis canadensis) provided
comparable but somewhat lower yields.
Timothy tended to be higher in digestible dry matter than most grasses,
but near to below average in CP, P, K, and Ca concentrations. Some
deficiencies occurred in energy values (DDM) and, except for red fescue,
in Ca concentrations of first-harvest herbage relative to the requirements
of a growing 500-lb steer. Crude protein of second-harvest herbage was
deficient for many grasses at two sites, and DDM was marginal to low
for some, but especially for bluejoint reedgrass