VALUE AND USE
SPECIES: Bouteloua gracilis | Blue Grama 



WOOD PRODUCTS VALUE : 
NO-ENTRY


IMPORTANCE TO LIVESTOCK AND WILDLIFE : 
Wildlife and all classes of livestock graze blue grama [4].  The species
has relatively low productivity because of its short growth form [51].
Growth begins in May or June, so blue grama provides little or no green
forage in the spring and early summer when foliage is scarce [47].
Although food value declines when the foliage is mature and dry [41], it
is still consumed and provides good fall and winter forage [47,51].

Blue grama is very tolerant of grazing and trampling [5].  It has
increased on many overgrazed ranges [47].  Large herbivores consume
spikelets throughout the year and disseminate seed widely [54].
Adaptative traits such as extreme resistance to grazing and seed
dispersal mechanisms suggest that this species has coevolved with large
herbivores.  

Many species of small birds and mammals consume blue grama seeds [49].


PALATABILITY : 
Blue grama is highly palatable to many species of wildlife and all
classes of livestock.  It remains palatable during the fall and winter
when the plant is mature and dried [51].  Bison in Oklahoma prefer it
[39].  In some areas, domestic sheep graze it preferentially [41].
Pronghorn graze blue grama sparingly [49].

Blue grama is heavily used by many species of small rodents [47].  It is
an important food of the northern pocket gopher during June, when it
shows maximum growth [48].  It is relatively unpalatable to them the
rest of the the year [48].

The degree of use shown by livestock and wildlife species for blue grama
in several western states is rated as follows [13]:


                      CO       MT       ND       UT       WY

Cattle               Good     Good     Good     Good     Good
Sheep                Good     Good     Good     Good     Good
Horses               Good     Good     Good     Good     Good
Pronghorn            ----     Poor     Poor     Fair     Fair
Elk                  ----     Poor     ----     Fair     Fair
Mule deer            ----     Poor     Poor     Fair     Poor
White-tailed deer    ----     ----     Poor     ----     Poor
Small mammals        ----     ----     Good     Good     Poor
Small nongame birds  ----     ----     ----     Good     Poor
Upland game birds    ----     ----     ----     Fair     Poor
Waterfowl            ----     ----     Fair     Poor     Poor


NUTRITIONAL VALUE : 
Blue grama is rated fair in protein and energy value [13].  In a Wyoming
study, blue grama magnesium and calcium levels decreased throughout the
growing season, and the plant was deficient in phosphorous by mid-August
[41].  By September, it had lost more than 46 percent of the original
crude protein content.  By end of October, it had lost 66 percent [41].
With fall rains and renewed growth, the decline of calcium and magnesium
stopped and protein content increased.

Frequent defoliation of blue grama during the growing season had little
effect on total carbohydrate reserves or nonstructural carbohydrates
[7].  Blue grama nutritional values as established by the National
Academy of Sciences [36] are as follows:
      
                 Aerial       Hay      Aerial     Aerial     Aerial 
                 Part         Early    Part       Part       Part   
                 Fresh        Bloom    Fresh      Fresh      Fresh  
                 Weathered             Immature   Mature     Dormant 
                 Mature        

Ash %                7.9       12.0      11.1       14.2      19.6
Crude Fiber         38.6       30.1      28.7       30.0      39.7    
Ether Extract %      1.1        2.2       1.8        1.7       2.7
N-free Extract %    48.9       44.4      46.9       46.2      31.7 
Protein (Nx6.25) %   3.5       11.3      11.5        7.9       6.3
Dig.Protein-cattle % 0.0        6.7       7.7        4.6       3.2
Dig.Protein-horses % 0.5        7.1       7.3        4.2       2.9
Dig.Protein-sheep %  0.2        7.1       7.7        4.4       2.9 
Ca %                 0.28       6.7       0.40       ---       ---
P %                  0.07       ---       0.16       ---       ---


COVER VALUE : 
Blue grama provides poor cover for small mammals, upland game birds, and
waterfowl [13]. 


VALUE FOR REHABILITATION OF DISTURBED SITES : 
Blue grama is well adapted for use in revegetating drier parts of the
central Great Plains [55].  Once established, it is persistent and
productive; it serves as a soil binder and helps prevent erosion [47].
Seedling establishment can, however, be difficult due to low seed
weight, the potential for only one seminal root, and limited capacity
for water uptake [55].  Attempts to seed abandoned cropland with blue
grama have been generally unsuccessful [54].  Lack of adequate soil
moisture is probably the major cause of planting failures.  The
following measures are recommended to minimize planting failures [56]:
(1) plant during favorable temperature regimes, (2) control weeds, (3)
prepare a firm seedbed so more water will move upward overnight, (4)
form shallow basins that will accumulate water, and (5) apply mulch to
conserve water.  Time of planting is critical for good establishment.
Two possible planting strategies are suggested [6]:  (1) plant early
when temperatures are marginal, but the probability of 2 or more
consecutive wet days is relatively high or (2) plant during midsummer
when temperatures are favorable, but the probability of 2 or more wet
days is low.

Blue grama seedlings can be transplanted.  Survival of 9-week-old
seedlings transplanted onto a Sonoran Desert site averaged 21 percent
after 32 months [9].  Transplant mortality may be related to dry soils
in spring [9].

Numerous blue grama cultivars have been developed including 'Hachita'
and 'Lovington,' both of which originated in New Mexico [23].
'Lovington' is well adapted for upland sites with medium-textured to
fine-textured soils in eastern New Mexico, northwestern Texas, and
southeastern Colorado [23].  Recommended planting dates are as follows
[49]:

                Region                   Planting Dates

           central Great Plains         April to mid-May
           southern Great Plains        April or before
           Southwest                    June 15 to July 15


OTHER USES AND VALUES : 
Blue grama is sometimes used in lawn mixtures [21].


MANAGEMENT CONSIDERATIONS : 
Blue grama is highly tolerant of livestock grazing and trampling [5] and
often increases on heavily grazed sites [51].  This may be due to its
ability to maintain a vigorous root system and adequate carbohydrate
reserves following defoliation [7].  Some of the leaves grow close to
the soil, so some photosynthetic tissue remains after grazing [51].

A greenhouse study showed frequent clipping did not severely reduce blue
grama's aboveground production [43].  Another experiment found optimum
production occurred when blue grama was clipped at 8-week intervals.  At
8-week intervals, aboveground production was maintained and root biomass
did not decrease [43].

Average recommended blue grama stubble height at termination of
season-long sheep grazing is 0.5 inch (1.3 cm) [35].  Rotation or
deferred rotation is advised to maintain production [49].  Blue grama is
more resistant to defoliation injury than western wheatgrass (Pascopyrum
smithii) [43].

Blue grama may compete with pinyon and juniper seedlings.  Like the
roots of those seedlings, its are roots concentrated in upper soil
layers [27].  Even though a blue grama stand may appear sparse, the
surface soil interspaces may be fully occupied by its extensive roots
[27].

Tree removal from old-growth pinyon-juniper woodlands generally results
in an increase in blue grama.  Schott and Pieper [45] noted an average
blue grama cover of 1.9 percent in old-growth stands, and 32.9 percent
cover in bulldozed stands.  Overgrazing may have promoted the spread of
junipers [27] beacuse it reduces the number of main roots and root
branches of blue grama [8].

Related categories for Species: Bouteloua gracilis | Blue Grama