Description
Improving the quality of irrigated pastures can increase the profitability of ruminant production systems. Increasing pasture plant biodiversity is beneficial for ruminants, pollinators, and soil health, but it is challenging to manage weed incursion in seeded mixed-species pastures. This study assessed the weed incursion that resulted when forage legumes or grasses were seeded as binary mixtures with one of four non-legume forbs. Defoliation occurred at 6-week intervals as either mowing or mob grazing. Forbs were chicory, plantain, Lewis flax, or small burnet and forages were alfalfa, birdsfoot trefoil, creeping foxtail, intermediate wheatgrass, kura clover, meadow bromegrass, orchardgrass, perennial ryegrass, reed canarygrass, sainfoin, smooth bromegrass, tall fescue, and white clover. Four defoliations per year occurred between May and September for two years. Eight replications were grouped into four blocks and each pair in a block was randomly assigned to the two defoliation treatments, mob grazing or mowing. Plots were 1.5 m2 and were assessed visually before each defoliation for the percentage of forage, forb, and weed. Chicory was the most dominant of the four forbs, and relative to legumes, most grasses suppressed both forb establishment and weed incursion under both grazing and mowing. There were no statistically significant effects of defoliation treatment on weed incursion.
Author ORCID Identifier
Jennifer MacAdam https://orcid.org/0000-0003-2349-9863
Xin Dai https://orcid.org/0000-0001-8821-0042
Document Type
Dataset
DCMI Type
Dataset
File Format
.txt, .xlsx
Publication Date
2-5-2025
Funder
Utah Agricultural Experiment Station
Publisher
Utah State University
Methodology
The cool-season grasses, temperate legumes, and non-legume forbs used in this study were planted 5–9 September 2005; legumes were treated with the relevant species of Rhizobium inoculant. Seeding rates were calculated to deliver 646 pure live seed (PLS) m−2. Sprinkler irrigation was used to apply water at a rate of 3.56 mm h−1 for 14 h for a total of 50 mm every 2 weeks during the growing season. Plots were defoliated on 14–18 May, 25–29 June, 6–10 August, and 17–21 September in 2007 and 26–30 May, 7–11 July, 18–22 August, and 29 September to 3 October in 2008. A single herd of beef heifers and cows grazed each of the four replications assigned to grazing for 24 h on successive days at a density of approximately 225,000 kg live weight ha–1, and paired replications were mowed or grazed over the same time period. The herd consisted of 15 beef heifers with a mean weight of 478 kg, and 10 beef cows with a mean weight of 676 kg. Prior to each defoliation, the proportion of cover provided by each of the two seeded species in each plot was visually estimated along with the proportion of cover due to species that had not been seeded (weeds). Bare soil was calculated by difference.
Referenced by
MacAdam, J., Gibbons, J., & Dai, X. (2025). Weed Incursion of Irrigated Forage–Forb Mixtures Under Mob Grazing or Mowing in the Mountain West USA. Agronomy, 15(1), 25. https://doi.org/10.3390/agronomy15010025
Start Date
2007
End Date
2008
Language
eng
Code Lists
Year
Year Sampled
Graz_Clp
Treatment; Grazed or Clipped
Forage
Seeded Forage Species
Forb
Seeded Forb Species
Tmt
Seeded Forage-Forb Mixture
Block
Replication
lp_forage
log of proportion of forage
lp_forb
log of proportion of forb
lp_weed
log of proportion of weed
lp_bare
log of proportion of bare ground
Paddock
Paddock number
Disciplines
Agricultural Science | Agriculture | Agronomy and Crop Sciences | Weed Science
License
This work is licensed under a Creative Commons Attribution 4.0 License.
Recommended Citation
MacAdam, Jennifer; MacAdam, Jennifer; and Dai, Xin, "Weed Incursion of Irrigated Forage–Forb Mixtures Under Mob Grazing or Mowing in the Mountain West USA" (2025). Browse all Datasets. Paper 241.
https://digitalcommons.usu.edu/all_datasets/241
Included in
Agricultural Science Commons, Agriculture Commons, Agronomy and Crop Sciences Commons, Weed Science Commons
Comments
The study was established with 8 replications. After establishment, pairs of replications were assigned to one of four blocks, and the two replications within each pair were randomly assigned to either grazing or mowing (which we referred to as clipping). The data reported in the paper were back transformed following statistical analysis.