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United States Department of Agriculture

Agricultural Research Service

Title: Tall and Fine Fescue: Relationship Between Growing Degree Days, Developmental Stage, and Nitrogen Acquisition

Authors
item Griffith, Stephen
item Bamberger, Machelle

Submitted to: Seed Production Research at Oregon State University
Publication Type: Experiment Station
Publication Acceptance Date: April 1, 2001
Publication Date: N/A

Interpretive Summary: The use of growing degree days (GDD) is becoming more widely accepted across the U.S. to compare genotypes and predict the rate of plant development. This is an important time scale to use by growers if their agricultural practices are based on plant developmental stages. For example, crop management practices that are linked to plant growth stages, such as pesticide, herbicide, or fertilizer applications or even cultivation can be timed based on an accumulated GDD time scale. From year to year, this time scale is much more consistent in predicting plant development than using calendar date. The technique is simple and does not require complicated plant development staging techniques. GDD accumulations involve the amount of accumulated heat required for plants to reach a certain stage of plant development. The study calculated GDD for two important grass seed production species grown in western Oregon, tall fescue and fine fescue, although this relationship holds true for most organisms if their growth and development is regulated by temperature (e.g., weeds, insects, pathogens). As mentioned, one practical use for the GDD time scale is with timing of fertilizer N application. For western Oregon, N applications between late winter and mid-spring, which equates to 400 to 900 GDD, has been shown to be sufficient for perennial ryegrass. This is different for earlier growing species, such as tall fescue and fine fescue. Both growth and N uptake occur earlier in the season for these two species.

Technical Abstract: The use of growing degree days (GDD) is becoming more widely accepted across the U.S. to compare genotypes and predict the rate of plant development. This is an important time scale to use by growers if their agricultural practices are based on plant developmental stages. For example, crop management practices that are linked to plant growth stages, such as pesticide, herbicide, or fertilizer applications or even cultivation can be timed based on an accumulated GDD time scale. From year to year, this time scale is much more consistent in predicting plant development than using calendar date. The technique is simple and does not require complicated plant development staging techniques. GDD accumulations involve the amount of accumulated heat required for plants to reach a certain stage of plant development. The study calculated GDD for two important grass seed production species grown in western Oregon, tall fescue and fine fescue, although this relationship holds true for most organisms if their growth and development is regulated by temperature (e.g., weeds, insects, pathogens). As mentioned, one practical use for the GDD time scale is with timing of fertilizer N application. For western Oregon, N applications between late winter and mid-spring, which equates to 400 to 900 GDD, has been shown to be sufficient for perennial ryegrass. This is different for earlier growing species, such as tall fescue and fine fescue. Both growth and N uptake occur earlier in the season for these two species.

Last Modified: 4/23/2014
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