Rangeland Ecology & Management

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Response of spotted knapweed and grass to picloram and fertilizer combinations
Author
Sheley, R. L.
Jacobs, J. S.
Publisher
Society for Range Management
Publication Year
1997-05-01
Body

Spotted knapweed (Centaurea maculosa Lam.) has reduced forage production, increased soil erosion, and lowered biodiversity on millions of hectares of rangeland throughout the western United States. Objectives of this study were to quantify the interaction between picloram (4-amino-3,5,6-trichloropicolinic acid) and fertilizer on spotted knapweed density and grass yield. Four picloram rates (0.0, 0.14, 0.28, and 0.42 kg ha-1) and 4 fertilizer rates (N+P: 0.0+0.0, 10.5+12.2, 21.1+26.4, and 31.7+39.6 kg ha-1) were applied to 3 spotted knapweed infested rangeland sites in a factorial combination arranged in a randomized-complete-block design during the spring of 1994. Grass yield and spotted knapweed density were measured at peak standing grass crop in 1994 and 1995. Data were analyzed as a split-plot in time using analysis of variance. Picloram and fertilizer did not interact to affect either spotted knapweed density or grass yield. All picloram treatments reduced spotted knapweed density to nearly zero. By 1995, all picloram treatments increased grass yield by an average of 1,500 kg ha-1. Fertilization did not affect spotted knapweed density, but the highest rates increased grass yield on those sites with a substantial residual grass understory. Combining fertilizer with picloram may enhance grass yield on sites with a residual of highly productive grasses. The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information. Migrated from OJS platform August 2020

Language
en
Resource Type
Text
Document Type
Journal Issue/Article
Digital Object Identifier (DOI)
10.2307/4003727
Additional Information
Sheley, R. L., & Jacobs, J. S. (1997). Response of spotted knapweed and grass to picloram and fertilizer combinations. Journal of Range Management, 50(3), 263-267.
IISN
0022-409X
OAI Identifier
oai:repository.arizona.edu:10150/644159
Journal Volume
50
Journal Number
3
Journal Pages
263-267
Journal Name
Journal of Range Management
Keywords
plant density
picloram
integrated control
Centaurea maculosa
application rates
fertilizer
Montana