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| ## composite dropseed {#composite-dropseed .Title-Header}             |
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| *Sporobolus compositus* (Poir.) Merr. var. *compositus*               |
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| Plant Symbol = SPCOC2                                                 |
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Contributed by: USDA NRCS Elsberry Plant Materials Center and the
National Plant Data Center

![](media/image3.jpeg){width="2.7993055555555557in"
height="4.229166666666667in"}

##### Alternate Names {#alternate-names .Header-3}

*Sporobolus* *asper*, *Sporobolus* *asper* var. *hookeri*, rough
dropseed, tall dropseed, zacaton

##### Uses {#uses .Header-3}

*Forage:* Composite dropseed is a minor portion of the vegetative
composition in most of the areas in which it grows. It is not a
particularly valuable forage species. The forage value of composite
dropseed, compared to other grasses, is fair for livestock and poor for
wildlife. It is most palatable in the spring when plants are in the
vegetative developmental stage and palatability declines as culms
mature. In Kansas composite dropseed tends to increase in overgrazed
bluestem pastures, but it tends to decrease in short-grass prairies.

*Prairie restoration and Roadside plantings:* On upland hardwood
forest-tallgrass prairies in central Oklahoma, the diet of cottontail
rabbit is dominated by composite dropseed, Heller\'s rosette grass
(*Dichanthelium* *oligosanthes*), and *Croton* species. Disturbed
habitats were maintained by removal of woody overstory vegetation with
herbicide and burning. Differences in the botanical composition and
quality of rabbit diets between disturbed and undisturbed habitats were
of little biological significance.

##### Status {#status .Header-3}

Please consult the PLANTS Web site and your State Department of Natural
Resources for this plant's current status (e.g. threatened or endangered
species, state noxious status, and wetland indicator values).

#####  {#section .Header-3}

##### Description {#description .Header-3}

*General*: Grass Family (Poaceae). Composite dropseed is a tall (2 to 4
ft.), native, perennial, warm-season bunchgrass. Culms are erect,
solitary or in small tufts, simple or branching, 24 to 48 inches tall,
solid and glabrous. Some varieties have short rhizomes. Inflorescences
are narrow panicles, 2 to 12 inches long and partially to completely
included in the upper sheaths. The inflorescences are either white or
pale purple in coloration. Composite dropseed flowers during late summer
to early autumn. The stems and leaves bleach whitish during winter.

*Distribution*: For current distribution, please consult the Plant
Profile page for this species on the PLANTS Web site.

*Habitat*: Composite dropseed occurs on prairies and foothills on dry
clayey to silty soils. It is most abundant on soils that are
intermittently wet and dry. It does not grow on either deep sandy soils
or on soils with a high water table. In the Great Basin composite
dropseed grows on dry often sandy sites in Juniper communities and in
fallow fields below 2,100 ft.

##### Adaptation {#adaptation .Header-3}

Composite dropseed is more drought tolerant than many grasses of the
bluestem prairie, but it is not as drought hardy as sand dropseed
(*Sporobolus* *cryptandrus*).

##### Establishment {#establishment .Header-3}

##### Pretreatment of composite dropseed seeds with potassium nitrate resulted in 39% germination. {#pretreatment-of-composite-dropseed-seeds-with-potassium-nitrate-resulted-in-39-germination. .Header-3}

##### Management {#management .Header-3}

Burning in early spring favors warm-season composite dropseed, whereas
late spring burning favors cool-season species. Forage yield of
composite dropseed increased following a spring burn during both wet and
dry years in an Ashe's juniper (*Juniperus* *ashe*) community in
southeastern Texas. An autumn burn favored the growth of composite
dropseed in a southern Texas chaparral community.

A field study addressed the effects of fire, cattle grazing and the
interaction of these two disturbances on plant species abundance and
community structure in an tallgrass prairie in Oklahoma. Plant species
composition was sampled across 4 levels of increasing disturbance
intensity: ungrazed + unburned (undisturbed), grazed + unburned,
ungrazed + burned, and grazed + burned. Burning occurred during
mid-April. Grazing occurred from mid-May to September at a moderate to
heavy stocking rate. Burning decreased the percentage cover of composite
dropseed from 11.7 to 4.8, when averaged across grazing treatments and
years. Grazing had no effect on the percentage cover of composite
dropseed. The common species in the plant community were classified as
either matrix or non-matrix species. Matrix forming species are superior
competitors that consume the majority of resources, and non-matrix
species occupy areas between the matrix forming dominants. In this study
the matrix species were perennial grasses: big bluestem (*Andropogon*
*gerardii*), little bluestem (*Schizachyrium* *scoparium*), Indiangrass
(*Sorghastrum* *nutans*), and composite dropseed. The non-matrix species
were perennial and annual forbs, and the annual grass cheatgrass
(*Bromus* *tectorum*). Collectively, the matrix and non-matrix species
exhibited an opposite response to both burning and grazing treatments.
Collectively, fire increased the cover of matrix-forming grass;
composite dropseed was an exception. Grazing decreased the cover of
matrix grasses and increased the cover of forbs. Cheatgrass was the most
common non-matrix species. Burning reduced the percentage cover of
cheatgrass from 30.0 to 1.8, when averaged across grazing treatments and
years.

##### Pests and Potential Problems {#pests-and-potential-problems .Header-3}

This plant may become weedy or invasive in some regions or habitats and
may displace desirable vegetation if not properly managed. Please
consult with your local NRCS Field Office, Cooperative Extension Service
office, or state natural resource or agriculture department regarding
its status and use. Weed information is also available from the PLANTS
Web site at plants.usda.gov.

##### Control {#control .Header-3}

Please contact your local agricultural extension specialist or county
weed specialist to learn what works best in your area and how to use it
safely. Always read label and safety instructions for each control
method. Trade names and control measures appear in this document only to
provide specific information. USDA NRCS does not guarantee or warranty
the products and control methods named, and other products may be
equally effective.

##### Seeds and Plant Production {#seeds-and-plant-production .Header-3}

##### An average seed lot of composite dropseed contains 759,362 seeds per pound. Observations indicate that cross-pollination in composite dropseed is possible but probably infrequent. Nevertheless, standard isolation procedures should be used in composite dropseed seed production.  {#an-average-seed-lot-of-composite-dropseed-contains-759362-seeds-per-pound.-observations-indicate-that-cross-pollination-in-composite-dropseed-is-possible-but-probably-infrequent.-nevertheless-standard-isolation-procedures-should-be-used-in-composite-dropseed-seed-production. .Header-3}

#####  {#section-1 .Header-3}

##### Cultivars, Improved, and Selected Materials (and area of origin) {#cultivars-improved-and-selected-materials-and-area-of-origin .Header-3}

Contact your local Natural Resources Conservation Service (formerly Soil
Conservation Service) office for more information. Look in the phone
book under "United States Government". The Natural Resources
Conservation Service will be listed under the subheading "Department of
Agriculture."

"Northern Missouri Germplasm" is a source identified ecotype for
northern Missouri counties. It was collected from native prairie
remnants in Missouri counties north of the Missouri River and from east
to west across northern Missouri. The potential uses of Northern
Missouri Germplasm include roadside plantings, prairie restoration,
landscaping, and increasing species diversity in prairie communities.
Seed is available from the USDA NRCS Elsberry Plant Materials Center,
2803 N. Hwy. 79, Elsberry, Missouri.

##### References {#references .Header-3}

##### Boe, A. 1990. *Variability for seed size and yield in two tall dropseed populations*. J. Range Manage. 43:195-197. {#boe-a.-1990.-variability-for-seed-size-and-yield-in-two-tall-dropseed-populations.-j.-range-manage.-43195-197. .Header-3}

#####  {#section-2 .Header-3}

##### Anderson, K.L., Smith, E.F. & Owensby, C.B. 1970. Burning bluestem range. *J. Range Manage.* 23: 81-92. {#anderson-k.l.-smith-e.f.-owensby-c.b.-1970.-burning-bluestem-range.-j.-range-manage.-23-81-92. .Header-3}

#####  {#section-3 .Header-3}

##### Baskin, C.J. & Baskin, J.M. 1998. *Seeds: Ecology, biogeography and evolution in dormancy and germination*. Academic Press. In: Native Plant Propagation Database <http://nativeplants.for.uidaho.edu/network/PreviewResults.asp> {#baskin-c.j.-baskin-j.m.-1998.-seeds-ecology-biogeography-and-evolution-in-dormancy-and-germination.-academic-press.-in-native-plant-propagation-database-httpnativeplants.for.uidaho.edunetworkpreviewresults.asp .Header-3}

#####  {#section-4 .Header-3}

##### Box, T.W. Powell, J.D. & Lynn, D. 1967. *Influence of fire on south Texas chaparral communities*. *Ecology* 48: 955-961. {#box-t.w.-powell-j.d.-lynn-d.-1967.-influence-of-fire-on-south-texas-chaparral-communities.-ecology-48-955-961. .Header-3}

#####  {#section-5 .Header-3}

##### Collins, S. 1987. *Interaction of disturbances in tallgrass prairie: a field experiment*. *Ecology* 68: 1243-1250.  {#collins-s.-1987.-interaction-of-disturbances-in-tallgrass-prairie-a-field-experiment.-ecology-68-1243-1250. .Header-3}

#####  {#section-6 .Header-3}

##### Kansas Wildflowers and Grasses. Accessed 20 October 2005 <http://www.lib.ksu.edu/wildflower/> {#kansas-wildflowers-and-grasses.-accessed-20-october-2005-httpwww.lib.ksu.eduwildflower .Header-3}

#####  {#section-7 .Header-3}

##### Riggins, R. 1977. *A biosystematic study of the Sporobolus asper complex (Gramineae)*. Iowa State Journal of Research 51: 287-321. {#riggins-r.-1977.-a-biosystematic-study-of-the-sporobolus-asper-complex-gramineae.-iowa-state-journal-of-research-51-287-321. .Header-3}

#####   {#section-8 .Header-3}

##### Peitz, D.G., Lockmiller R.L, Leslie, D.M. & Engle, D.M. 1997. *Protein quality of cottontail rabbit forages following rangeland disturbance*. *J. Range Manage.* 50: 450-458.  {#peitz-d.g.-lockmiller-r.l-leslie-d.m.-engle-d.m.-1997.-protein-quality-of-cottontail-rabbit-forages-following-rangeland-disturbance.-j.-range-manage.-50-450-458. .Header-3}

#####  {#section-9 .Header-3}

##### Stubbendieck, J., Hatch, S.L. & Butterfield, C. 1995. *North American range plants.* ed. 2. University of Nebraska Press, Lincoln.  {#stubbendieck-j.-hatch-s.l.-butterfield-c.-1995.-north-american-range-plants.-ed.-2.-university-of-nebraska-press-lincoln. .Header-3}

#####  {#section-10 .Header-3}

##### USDA Forest Service. *Fire effects information system*. Accessed 20 October 2005 <http://www.fs.fed.us/database/feis/> {#usda-forest-service.-fire-effects-information-system.-accessed-20-october-2005-httpwww.fs.fed.usdatabasefeis .Header-3}

#####  {#section-11 .Header-3}

##### USDA NRCS. 2006. *The PLANTS database*. \<http://plants.usda.gov\>. Accessed: 23March2006. National Plant Data Center, Baton Rouge, Louisiana {#usda-nrcs.-2006.-the-plants-database.-httpplants.usda.gov.-accessed-23march2006.-national-plant-data-center-baton-rouge-louisiana .Header-3}

#####  {#section-12 .Header-3}

##### Wink, R.L. & Wright, H.A. 1973. *Effects of fire on an ashe juniper community*. J. Range Manage. 26: 326-329. {#wink-r.l.-wright-h.a.-1973.-effects-of-fire-on-an-ashe-juniper-community.-j.-range-manage.-26-326-329. .Header-3}

#####  {#section-13 .Header-3}

##### Prepared By {#prepared-by .Header-3}

USDA NRCS Elsberry Plant Materials Center and James Henson, National
Plant Data Center

##### Species Coordinator {#species-coordinator .Header-3}

USDA NRCS Elsberry Plant Materials Center, Elsberry, Missouri

##### Edited: 23March2006 jsp {#edited-23march2006-jsp .Header-4}

For more information about this and other plants, please contact your
local NRCS field office or Conservation District, and visit the PLANTS
Web site\<[http://plants.usda.gov](http://plants.usda.gov/)\> or the
Plant Materials Program Web site
\<[http://Plant-Materials.nrcs.usda.gov](http://Plant-Materials.nrcs.usda.gov/)\>

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large print, audiotape, etc.) should contact USDA\'s [TARGET
Center](http://www.usda.gov/oo/target.htm) at 202-720-2600 (voice and
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*To file a complaint of discrimination write USDA, Director, Office of
Civil Rights, Room 326-W, Whitten Building, 14th and Independence
Avenue, SW, Washington, DC 20250-9410 or call 202-720-5964 (voice or
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*Read about [Civil Rights at the Natural Resources Convervation
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