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ARS Home » Midwest Area » Madison, Wisconsin » U.S. Dairy Forage Research Center » Dairy Forage Research » Research » Publications at this Location » Publication #310226

Research Project: Redesigning Forage Genetics, Management, and Harvesting for Efficiency, Profit, and Sustainability in Dairy and Bioenergy Production Systems

Location: Dairy Forage Research

Title: Grass and legume effects on nutritive value of complex forage mixtures

Author
item Brink, Geoffrey
item Sanderson, Matt
item Casler, Michael

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2014
Publication Date: 3/3/2015
Publication URL: http://handle.nal.usda.gov/10113/62452
Citation: Brink, G.E., Sanderson, M.A., Casler, M.D. 2015. Grass and legume effects on nutritive value of complex forage mixtures. Crop Science. 55(3):1329-1337.

Interpretive Summary: Grazing-based producers typically seed complex mixtures of cool-season grasses and legumes to improve pasture productivity and forage quality. Although we know that productivity is often influenced by the growth of one or two dominant species in the mixture, the impact on forage quality by individual species is less known. We seeded combinations of two grasses and two legumes that resulted in forage mixtures having a wide range in composition (0 to 100%) of each of four species. We found that when harvested at an early stage of growth which is typical with grazing, some grasses and legumes did not have a predictable impact on the quality of complex mixtures. The addition of a high-quality grass like meadow fescue improved quality as its contribution increased, while a high-quality legume such as alfalfa had a relatively small effect compared to white clover. The results indicate that meadow fescue and white clover have the greatest potential to positively influence pasture quality. This information is useful to grazing-based livestock producers seeking to improve the nutritive value of pastures.

Technical Abstract: Productivity of complex forage mixtures is typically influenced by a dominant species, but nutritive value may be a function of multiple components. Two experiments with 15 mixtures and monocultures of orchardgrass (Dactylis glomerata L.), quackgrass (Elytrigia repens L.), alfalfa (Medicago sativa L.), and white clover (Trifolium repens L.), and of meadow fescue [Schedonorus pratensis (Huds.) P. Beauv.], reed canarygrass (Phalaris arundinacea L.), red clover (T. pratense L.), and kura clover (T. ambiguum L.) were conducted in Pennsylvania and Wisconsin during two years. Vegetative-stage mixtures were harvested five times each year. Botanical composition was determined in spring, summer, and fall and used to calculate each component’s additive effect, or the expected change in nutritive value associated with a change in botanical composition of a species from 0 to 100%. Nutritive value differences among mixtures attributed to botanical composition were evident the first year, but except for monocultures, had largely disappeared in the second year. White clover and meadow fescue generally had a positive additive effect on herbage digestibility (range of 36 to 80 g kg-1), but alfalfa and reed canarygrass had no significant additive effect on in vitro digestibility. Legumes generally had a negative additive effect (range of -179 to -81 g kg-1) and grasses a positive effect (range of 81 to 166 g kg-1) on herbage neutral detergent fiber (NDF). The results suggest that species with high nutritive value relative to other species within the same functional group have a disproportionate effect on nutritive value of complex mixtures.