Integrating partial root-zone drying and saline water irrigation to sustain sunflower production in freshwater-scarce regions

Abstract

Applying saline water resources for irrigating croplands requires serious attentions when sustainable agriculture is considered. A two-year field investigation was carried out in a drip-irrigated sunflower field under six irrigation treatments, including (i) full freshwater irrigation (FI), full irrigation with diluted seawater (DS) (SI), alternate DS-freshwater irrigation (FSI), freshwater-PRD (partial root-zone drying) irrigation with 25 % less water than full (PRD1), DS-PRD irrigation with 25 % less water than full (PRD2), alternate DS-freshwater irrigation under PRD with 25 % less water than full (PRD3), in three replicates. Compared to the FI treatment, crop yield was reduced by 3.1–32 %, with the lowest one under PRD1. Among the DS treatments, PRD3, resulted in the highest grain yield (4306 kg ha−1), grain nitrogen content (2.83 %), oil yield (1907 kg ha−1) and irrigation water productivity (1.10). PRD3 also saved freshwater by 20 %, and kept soil salinity of the rooting-zone below the maximum crop tolerance threshold. Based on the results, PRD3 might be a cost-effective pathway which guarantees the sustainable application of diluted seawater in the irrigated sunflower lands.