Water Use and Water Productivity of Sugarbeet, Malt Barley, and Potato as Affected by Irrigation Frequency

Successful irrigation management is one of the most important agronomic practices for achieving profitable yield and maximizing crop water productivity (CWP) while maintaining environmental quality by minimizing water losses to runoff-and deep drainage. This study was conducted to compare the influence of two irrigation frequencies on crop water use (CWU) and CWP of sugarbeet (Beta vagaris L.), malt barley (Hordeum vulgare L.), and potato (Solanum tuberosum L.) on a sandy loam soil in the semiarid northern Great Plains. The irrigation frequencies compared were: high frequency (HF) irrigation with biweekly application of small irrigation quantities, and the conventional low frequency (LF) with weekly application of large irrigation quantities. Irrigation frequency was varied based on either 15 mm (HF) or 30 mm (LF) cumulative crop evapotranspiration replacements. Seasonal CWU amounts were determined using the water balance equation of sugarbeet, malt barley, and potato under HF and LF irrigations for 2007, 2008, 2009, 2010, and 2011. No significant differences due to irrigation frequency were found for yield, CWU, and CWP of sugarbeet (root and sucrose), malt barley, or potato. Small differences in CWU values between HF and LF irrigations were due to variations in soil moisture content in the soil profile and drainage losses below the 0.91-m soil depth. Conventional LF irrigation thus can sustain yield, improve water use, and reduce net economic input as feasibly as HF irrigation practices when a self-propelled automated sprinkler system is used on a sandy loam soil.