Forage Nutritive Value and Palatability of Perennial Weeds
- G. C. Marten,
- C. C. Sheaffer and
- D. L. Wyse2
Knowledge of forage quality of individual weed species is essential for making sound management decisions regarding the control of weeds that invade alfalfa (Medicago sativa L.). Our objective was to determine the nutritive value and palatability of nine perennial forb and grass weeds in comparison to alfalfa and smooth bromegrass (Bromus inermis Leyss.). Field trials were conducted on a fine-silty over sandy skeletal, mixed, mesic Typic Hapludoll. We used a randomized complete block design with four replicates. Compared to alfalfa, smooth bromegrass and quackgrass [Agropyron repens (L.) Beauv.] consistently had more neutral detergent fiber (NDF), less crude protein (CP), and similar in vitro digestibility (IVDDM). Grasses consistently had more NDF than forbs. Nutritive value varied considerably among forbs. Jerusalem artichoke (Helianthus tuberosus L.), Canada thistle [Cirsium arvense (L.) Scop.], dandelion (Taraxamum officinale Weber in Wiggers), and perennial sowthistle (Sonchus arvnesis L.) had CP and IVDDM concentrations equal to or greater than those of alfalfa, while Jerusalem artichoke, dandelion, and curly dock (Rumex crispus L.) frequently had lower NDF concentrations than that of alfalfa. Forb weeds generally had lower palatability than alfalfa or smooth bromegrass, with several exceptions. Jerusalem artichoke, curly dock, hoary alyssum [Berreroa incana (L.) DC.], and Canada thistle were either completely or nearly completely rejected by grazing lambs (Ovis spp.). Palatability of a quackgrass biotype selected for wide leaves was equal or superior to smooth bromegrass and was equal to alfalfa in two of three trials. Common quackgrass consistently had lower palatability than smooth bromegrass or alfalfa. Because forage quality of perennial weeds varied considerably among species and was sometimes superior to that of alfalfa, we conclude that decisions on whether to implement weed control in established alfalfa should be specific for each situationPlease view the pdf by using the Full Text (PDF) link under 'View' to the left.
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