Degree-day accumulation is commonly used to predict crop development and harvest dates. Relationships between degree-day accumulation and phenological development of range forage grasses have received less attention. This research tested the hypotheses that leaf development by big bluestem [Andropogon gerardii Vitman] and little bluestem [Schizachyrium scoparium (Michx.) Nash] is related to degree-day accumulation and that these relationships are stable over environments and years within environments. Study environments included native prairie, a space-planted garden, and a growth chamber. Individual tillers of big and little bluestem were permanently marked and fully developed leaves were counted once or twice weekly over 3 growing seasons and 1 growth chamber trial. Quadratic regression models accounted for 94 to 99% of the observed variation in leaf development for all species-environment-year combinations. Regression models were significantly different (p = 0.05) among environments and between years within environments. Lack of model stability over years was a result of high variation in total leaves produced per tiller relative to annual variation in degree-day accumulation. The simple independent variable, day of year, predicted leaf development equally as well as degree-day accumulation. This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries. The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information. Migrated from OJS platform August 2020
Scholarly peer-reviewed articles published by the Society for Range Management. Access articles on a rolling-window basis from vol. 1, 1948 up to 5 years from the current year. Formerly Journal of Range Management (JRM). More recent content is available by subscription from SRM.