Supplemental irrigation and fall dormancy effects on alfalfa productivity in a semiarid, subtropical climate with a bimodal precipitation pattern Academic Article uri icon

abstract

  • Alfalfa (Medicago sativa L.) is an important hay crop produced under rainfed conditions or various levels of irrigation in the southern Great Plains of the USA. The objective of this study was to determine the role of fall dormancy (FD) on productivity and forage nutritive value of alfalfa in rainfed and supplemental irrigation systems in a semiarid, subtropical climate with a bimodal pattern of precipitation. Cultivars with FD ratings of 1 to 3 (dormant), 4 to 6 (moderately dormant), and 7 to 8 (nondormant) were planted in November 2001 on a Miles fine sandy loam (fineloamy, mixed, Thermic Udic Paleustalfs) near Vernon, Texas in two adjacent, randomized, completeblock experiments representing rainfed and supplemental irrigation systems. In the supplemental irrigation system, water was supplied during April to October to meet the longterm average monthly precipitation. During 20022005, plants were defoliated to 5 cm height at 5 to 15% bloom in all cultivars. In the rainfed system, FD had no effect on productivity (5.66.0 Mg ha1). Nondormant cultivars produced higher dry matter yield (20.2 Mg ha1) than dormant cultivars (15.9 Mg ha1) under supplemental irrigation. Moderately dormant cultivars were intermediate (18.6 Mg ha1). Forage nutritive value was greater in the spring (rainfed) or spring and autumn (supplemental irrigation) than in the summer. Weather patterns and harvest time interacted with FD in determining forage nutritive value under supplemental irrigation. Cultivars with FD ratings of 5 to 8 may be used in similar environments of the southern Great Plains to maximize productivity of alfalfa.

published proceedings

  • AGRONOMY JOURNAL

author list (cited authors)

  • Malinowski, D. P., Pinchak, W. E., Kramp, B. A., Zuo, H., & Butler, T. J.

citation count

  • 20

complete list of authors

  • Malinowski, DP||Pinchak, WE||Kramp, BA||Zuo, H||Butler, TJ

publication date

  • May 2007

publisher