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United States Department of Agriculture

Agricultural Research Service

Title: How Does Plant Population Affect the Yield, Quality, and Canopy of Native Bluestem (Andropogon SPP.) Forage?

Authors
item Springer, Timothy
item Gillen, Robert

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 28, 2006
Publication Date: January 22, 2007
Citation: Springer, T.L., Gillen, R.L. 2007. How does plant population density affect the yield, quality, and canopy of Native Bluestem (Andropogon spp.) forage? Crop Science. 47:77-82.

Interpretive Summary: The density at which a crop is grown is known to affect its growth and quality. Little, however, is known about how plant density affects the growth of perennial forage grasses. Springer and Gillen (xxx-xxx) studied the effects of plant density on the forage yield, forage quality, and plant canopy structure of two native bluestem (Andropogon spp.) species. They found that the optimum plant density for forage production was between 6.0 and 8.0 plants m-2, however, this was not the optimum for crude protein (CP) concentration. CP was highest at densities of 1.2 and 10.8 plants m-2. The greatest leaf area m-2 was at the 10.8 plants m-2 density. A plant population density of 10.8 plants m-2 would produce the most palatable and the highest quality forage with only slight reduction in total DM yield.

Technical Abstract: The density at which a crop is grown is known to affect its growth and quality. Little, however, is known about how plant density affects the growth of perennial forage grasses. The objectives of this study were to investigate the effects of plant population density on the forage yield, forage quality, and plant canopy structure of two native bluestem species. Big bluestem (Andropogon gerardii Vitman) and sand bluestem (A. hallii Hack.) were established at six plant densities (1.2, 1.8, 2.7, 3.6, 5.4, and 10.8 plants m'2) in a split plot design with plant density as the main plot factor and bluestem species as the subplot factor. Data were analyzed with a mixed model analysis of variance. Fixed effects were species, plant density, and species x plant density interactions. Blocks within year were random effects. The optimum plant density for forage production was between 6.0 and 8.0 plants m-2. This was not, however, the optimum for crude protein (CP) concentration. As plant density increased, CP followed a quadratic response. CP was highest at 1.2 and 10.8 plants m-2 densities. The greatest leaf area m-2 was at the 10.8 plants m-2 density. At 10.8 plants m-2, the average yield loss from maximum was about 13 % dry matter (DM). Also at 10.8 plant m-2 the CP concentration was 11 % higher than that of forage produced at 5.4 plants m-2. A plant population density of 10.8 plants m-2 would produce the most palatable and the highest quality forage with only slight reduction in total DM yield.

Last Modified: 10/25/2014
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