• IMPORTANCE TO LIVESTOCK AND WILDLIFE
• PALATABILITY
• NUTRITIONAL VALUE
• COVER VALUE
• VALUE FOR REHABILITATION OF DISTURBED SITES
• OTHER USES AND VALUES
• MANAGEMENT CONSIDERATIONS

IMPORTANCE TO LIVESTOCK AND WILDLIFE:

Black grama is considered excellent forage for all livestock classes and wildlife [108].

Cactus wrens in the southern Chihuahua Desert of New Mexico and Arizona use black grama as a minor component of their nests [86].

PALATABILITY:

Black grama provides highly palatable, yearlong forage for domestic cattle [91].

NUTRITIONAL VALUE:

Overall, black grama is one of the most nutritious desert winter grasses for livestock [90]. The protein content of perennial grasses is generally high when individuals are developmentally young, and declines rapidly with maturity. In Texas, high protein percentages for black grama were observed in June, with the lowest percentages occurring in February and March [48]. In New Mexico arid ranges, black grama protein content varied little throughout the year. Calcium values were considered adequate throughout the year. Phosphorus varied from 0.07% to 0.12%, with the highest levels occurring from June to October.

Nutritional value (%) of fresh black grama varied seasonally as follows [88]:

	Aerial Part- immature	Aerial Part- early bloom	Aerial Part- mature
Ash	8.5	9.5	6.7
Crude fiber	30.3	30.7	33.1
Ether extract	1.7	1.8	1.6
Carotene	---	---	26.0
Ca	0.38	0.42	0.22
P	0.16	0.16	0.11
N-free extract	48.0	49.8	52.2
Protein (N × 6.25)	11.5	7.4	6.4
Digestible protein
cattle	7.7	5.8	3.3
horses	7.3	5.4	3.0
domestic sheep	7.7	5.7	3.0

COVER VALUE:

No entry

VALUE FOR REHABILITATION OF DISTURBED SITES:

Black grama is generally not recommended for reseeding projects due to low seed viability. Obtaining high quality seed is difficult; supplies of good seed are scarce [4].

Black grama is a poor competitor with perennial snakeweeds (Gutierrezia spp.), although snakeweeds commonly occur in black grama-dominated grasslands [82].

A "good stand" of black grama was established in the northern Chihuahuan Desert by constructing small dikes on arroyos and then reseeding areas just upland from the dikes with native species. Black grama produced seed 2 years after establishment, in a summer of favorable rains, and floodwaters dispersed the seeds downstream [6].

OTHER USES AND VALUES:

Black grama produces excellent hay when not under water stress [108].

MANAGEMENT CONSIDERATIONS:

Black grama shows variable tolerance to grazing, with several abiotic and biotic factors contributing to overall grazing response. In general, black grama decreases under grazing [71]. Vigor is extremely impaired by heavy grazing; however, black grama is tolerant of light grazing [44]. Black grama in the Southwest showed better response to light grazing than moderate grazing [62].

Population increases for black grama are greatest under grazing exclusion, due to reliance upon stoloniferous regeneration [29]. Stolons growing horizontally outward from tufts are very susceptible to grazing and trampling damage [114], and intense grazing pressure may shift regeneration of black grama from stoloniferous expansion to tillering [91]. Stoloniferous expansion of black grama can be successful with careful grazing management, however. To encourage vegetative reproduction, grazing removal of 30 to 35% of total annual production is recommended. Herbage removal of more than 65% of annual production is not recommended [85].

The season of grazing influences black grama tolerance. In general, black grama is readily damaged under summer grazing. Fall, winter, and spring grazing produce less damage [66]. Defoliating black grama continuously throughout the growing season produces less forage the following year compared to defoliating during culm expansion [85]. Season of grazing also affects black grama regeneration. Protection from summer grazing favors successful black grama regeneration by allowing stolons to root [29].

A simulated grazing study was conducted in the Jornada Experimental Range of New Mexico. Clippings left 1-inch (2.5 cm) and 2-inch (5 cm) black grama stubble heights. After 11 years, neither 1-inch nor 2-inch clipping treatments produced as much as 4% the original tuft area, and there were severe declines in stolon regeneration. The decreased tuft area allowed for wind erosion of the upper loose soil mulch, which is required for successful stolon rooting [28].

All other factors aside, there is a correlation between degree of grazing intensity and black grama regrowth. Black grama vigor was greater on lightly and moderately grazed plots during both below normal and above-normal precipitation during the growing season. Results over a 9-year period comparing a light¹, moderate², and recommended (for maintaining and increasing black grama on range land) ³ grazing regimes are summarized below [114].

Grazing	Seedstalk height (in.)	Stolons/plant	Stolon length (in.)	Rooted sets/plant
Light	14.8	2.8	5.4	0.31
Moderate	13.8	2.6	5.0	0.28
Recommended	13.0	2.1	4.6	0.19

¹ = Average herbage grazed = 19%
² = Average herbage grazed = 25.8%
³ = Average herbage grazed = 36.2%

Seedling establishment of black grama in southern Arizona was greater in ungrazed areas compared to grazed areas. Mean density (new plants/m²) and seedling survivorship was as follows [30]:

New plants/m²  (17-year mean)                

Grazed	Ungrazed
2.8	6.4

1st-year seedling survivorship (%)  (17-year mean)

Grazed	Ungrazed
35.8	38.8

Related categories for SPECIES: Bouteloua eriopoda | Black Grama