See more from this Division: C06 Forage and Grazinglands
See more from this Session: Leguminous Forages for a Nitrogen-Starved World
Wednesday, 8 October 2008: 9:15 AM
George R. Brown Convention Center, 371F
Keith Gerard Pembleton1, Richard Rawnsley2, Jeffrey Volenec3, Danny Donaghy2 and Stuart Smith4, (1)Tasmanian Institute of Agricultural Research, Univ. of Tasmania, Burnie, Australia
(2)Tasmanian Institute of Agricultural Research, University of Tasmania, Burnie, Australia
(3)Purdue Univ., West Lafayette, IN
(4)Tasmanian Department of Primary Industries and Water, Prospect, Australia
Abstract:
The dry matter yield of alfalfa (Medicago sativa L.) is made up of three principle yield components; mass per shoot, shoots per plant and plant density. This study investigated the influence of genotype and environment on alfalfa yield components for one year from establishment in Tasmania, Australia. Four cultivars were established in the spring and summer of 2006/07 at two contrasting environments, Elliott (41°4’48” S, 145°46’12” E, 1200mm annual rainfall, Humic Eutrodox soil) and Cambridge (42°49’48” S, 147°30’00”E, 500mm annual rainfall, Udic Haplustalfs soil) in Tasmania. Cultivars chosen to give a wide representation of fall dormancy (FD) were DuPuits (FD3), Grasslands Kaituna (FD4.5), SARDI-7 (FD7) and SARDI-10 (FD10). Yield and yield components of the rain grown crops were monitored for six harvests at each location.
Yield was affected (P<0.05) by cultivar in the late spring harvest at Elliott and the late summer harvests at Cambridge. Yields of all cultivars were consistently greater at Elliott than at Cambridge apart from the late summer harvest where yields were similar. Cultivar affected (P<0.05) at least one yield component in half the harvests in each environment. However, the yield component that was affected was not consistent, nor was the harvest in which the effects were detected.
Stepwise multiple logistical regressions of yield components against yield at each harvest showed that mass per shoot consistently had the largest influence on yield. At some harvests it was found that plant density also had a significant influence on yield, however, the effect was not consistent across all harvests. Shoots per plant rarely made a significant addition to the multiple regression model.
The development of best management practices for alfalfa in this environment needs to focus on maximising mass per shoot and to a lesser extent plant density to ensure the yield potential of alfalfa is reached.
See more from this Division: C06 Forage and Grazinglands
See more from this Session: Leguminous Forages for a Nitrogen-Starved World