Surfactant application on growth characteristics of onion (crystal white var.) under saline water irrigation condition

Successful management of saline water could have significant potential for agricultural development inmany areas, particularly in water-scarce regions. The experiment with a factorial arrangement for treatments was conducted based on a randomized complete block design with four replications at the Research Greenhouse of California State Polytechnic University, Pomona in 2016. Two levels of salinity were employed in the irrigation water during the growth period which maintained the electrical conductivity (EC) of soil at: 0 (control), and 4 dS/m. Also, different non-ionic surfactant types (ACA1848 and ACA2994) and surfactant rates (0, 1, 2, 4 ppm) were treated to the plots. The results of the experiment showed that saline water (4 dS/m) reduced plant height, shoot dry weight, fresh bulb weight, dry bulb weight compared to fresh water condition. Irrigation water treatment by surfactant type 1848 was beneficial for onion growth and development in fresh and saline irrigation water conditions. Surfactant application had a moderating effect against the adverse condition of saline water. Also, Fresh water irrigation with surfactant types 1848 and 2994 were most beneficial at 4 and 2ppm rates, respectively. However, in saline water irrigation, only application of surfactant type 1848 at 2ppm showed a beneficial effect on onion growth and development. In fact, the surfactant application significantly improves all growth traits of onion which indirectly enhances the tolerance of plants to salinity stress.