Deficit irrigation: a viable option for sustainable confection sunflower (Helianthus annuus L.) production in the semi-arid US

Abstract

With water resources becoming more limited in arid and semi-arid regions, water-saving strategies are needed to reduce agricultural water use. A furrow-irrigated field experiment was conducted during 3 years (2010–2012) in the western US to evaluate the response of confection sunflower to deficit irrigation. Treatments were full irrigation (FI, irrigation as scheduled by farmers), two deficit irrigation strategies (R1, started irrigation when miniature floral heads appeared; and R4, started irrigation when floral heads began to open), and rainfed (CK) as control. Results showed that growth and yield of confection sunflower were significantly affected by treatments. The FI and deficit irrigation treatments (R1 and R4) led to significantly higher leaf area index (LAI), aboveground biomass, head diameter, and yield compared with the CK treatment. Relative to FI, deficit irrigation decreased sunflower LAI, head diameter, and aboveground biomass. Average yield was 6% and 15% less in R1 and R4 treatments, respectively, compared with the FI treatment. There was no significant difference in yield between FI and R1, except during extremely dry years, suggesting that the R1 strategy may maintain yield while reducing one irrigation event. Based on the growth and yield of sunflower, an irrigation for crop establishment and then resuming of irrigation at the R1 stage could be considered as a water-saving strategy for surface-irrigated confection sunflower grown in water-scarce regions.