Location: Northwest Irrigation and Soils ResearchTitle: Effect of deficit irrigation timing on sugarbeet Author
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/29/2017
Publication Date: 7/13/2017
Citation: Tarkalson, D.D., King, B.A. 2017. Effect of deficit irrigation timing on sugarbeet. Agronomy Journal. 109(5):2119-2127. doi:10.2134/agronj2017.01.0061. Interpretive Summary: Increased water demands and drought have resulted in a need to determine the impact of deficit water management practices in irrigated sugarbeet production. Understanding the impacts of these alternative water management practices on production are needed to guide irrigation scheduling in water limiting situations. This study was conducted at the USDA Agricultural Research Service, Northwest Irrigation and Soils Research Laboratory in Kimberly, ID. Eight irrigation treatments were compared using a surface drip irrigation system. The treatments consisted of varying rates of water application in relation to the full amount needed for the crop, combined with application timing. Results showed that under deficit irrigation, higher yields were obtained when water was applied evenly throughout the season or 100 percent of crop water needs was applied early with deficit irrigation later in the season. Sugarbeet with severe water stress early in the season followed by 100 percent crop water needs later in the season had lower yield.
Technical Abstract: Increased water demands and drought have resulted in a need to determine the impact of deficit water management in irrigated sugarbeet (Beta vulgaris L.) production. This study was conducted over 3 yr at USDA-ARS in Kimberly, ID, on a Portneuf silt loam soil. Eight irrigation treatments consisted of crop evapotranspiration (ETc) rates combined with application timing. Treatments were: W1 Even: approximately (approximately) 100% ETc evenly throughout the growing season; W2 Even: approximately 65% crop evapotranspiration; W2 Early: approximately 100% ETc early in season, approximately 55% ETc the remainder of the season; W2 Late: rain-fed from emergence to end of July, approximately 100% ETc the remainder of the season; W3 Even: approximately 40% ETc; W3 Early: approximately 100% ETc early in season, approximately 25% the remainder of the season; W3 Late: rain-fed through mid-August, approximately 100% ETc the remainder of the season, and rain-fed: no post emergence irrigation. Results showed that within deficit irrigation treatments, higher yields were obtained when water was applied evenly throughout the season (Even) or approximately 100% of ETc was applied early with deficit irrigation later in the season (Early). Thus, the W2 Even and W2 Early treatments had 31.6, 32.9, and 28.2% greater estimated recoverable sucrose (ERS) yields compared to the W2 Late treatment in 2011, 2012, and 2016, respectively. Across all years, ERS yields increased at rates ranging from 17.3 to 22.0 kg ha–1 mm–1 actual crop water evapotranspiration (ETa). Generally, sugarbeet with greater water stress early in the season followed by approximately 100% ETc later had lower yields and sucrose content (late treatments).