Alfalfa Irrigation during Drought

Abstract

Alfalfa yields decrease when water supply is inadequate. In drought years, starting and continuing with full irrigation until the water supply has been exhausted will limit full production to earlier harvests. The objective of this study was to examine the effect of discontinued irrigation on alfalfa yield during the irrigation season and when water supply is restored in the following year. Three irrigation levels, water for two harvests (i1), water for 3 harvests (i2), and water for four harvests (i3), were imposed in 1981–83 and one irrigation level (i3) in 1984. Yield response was compared among il–i3 by harvest for 1981–83 and separately for 1984, between flood and sprinkler irrigation, and between drainage and no drainage. Generally, yields were significantly less for nonirrigation conditions, they fully recovered in 1984 after three years of deficit irrigation, yield of harvests 1 did not differ between 1984 and 1982–83, drainage condition did not affect yield, and irrigation method had a significant influence on yield for harvests 3 and 4 in 1981–83.