Western ragweed effects on herbaceous standing crop in Great Plains grasslands
Issue Date
2000-05-01Keywords
height-weight ratiotallgrass prairie
mixed prairie
mixed pastures
Ambrosia psilostachya
growth curve
rain
Oklahoma
plant communities
plant density
prairies
biomass
botanical composition
plant competition
grazing
grasses
Ambrosia psilostachya
plant competition
grazing effects
Metadata
Show full item recordCitation
Vermeire, L. T., & Gillen, R. L. (2000). Western ragweed effects on herbaceous standing crop in Great Plains grasslands. Journal of Range Management, 53(3), 335-341.Publisher
Society for Range ManagementJournal
Journal of Range ManagementAdditional Links
https://rangelands.org/Abstract
Western ragweed [Ambrosia psilostachya DC. ], a major forb species in mixed and tallgrass prairies, is considered to have little value for cattle grazing but is an important food item for bobwhite quail [Colinus virginianus]. While often thought to be a strong increaser with grazing pressure, information on the actual relationship between western ragweed and grasses is contradictory. Our objectives were to 1) determine the effect of western ragweed on grass standing crop, and 2) determine the effect of vegetation type and grazing on survival and shoot morphology of western ragweed. Western ragweed did not appear to reduce grass standing crop. Instead, standing crop (40 to 620 kg ha-1) and density (6 to 41 shoots m-2) of western ragweed were positively related to grass and grass-forb standing crop in mixed prairie. Standing crop of western ragweed was not related to grass standing crop in tallgrass prairie. Competitive thresholds for western ragweed in mixed and tallgrass prairies appear to be above the levels observed in this study. Density of western ragweed shoots decreased over the growing season under both grazed and ungrazed treatments. Survival of western ragweed shoots from June to September was greater in mixed prairie (81%) than in tallgrass prairie (63%) and was greater in ungrazed (76%) than grazed plots (68%). Western ragweed shoots weighed less per unit of height in tall grassprairie. Western ragweed shoots in ungrazed plots were taller than shoots in grazed plots but weighed less per unit of height. These differences in shoot morphology are consistent with increased competition for light in tallgrass prairie and in ungrazed sites. Western ragweed may not directly reduce grass standing crop but, rather, increase only when grasses are reduced by other stresses such as improper grazing.Type
textArticle
Language
enISSN
0022-409Xae974a485f413a2113503eed53cd6c53
10.2307/4003442