Spinach biomass yield and physiological response to interactive salinity and water stress

Authors: ORS, SELDA - Ataturk University; Suarez, Donald

Submitted to: Agricultural Water Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/7/2017
Publication Date: 5/24/2017
Citation: Ors, S., Suarez, D.L. 2017. Spinach biomass yield and physiological response to interactive salinity and water stress. Agricultural Water Management. 190:31-41. doi: 10.1016/j.agwat.2017.05.003.

Interpretive Summary: The western U.S. is facing a critical shortage of fresh water, as are all arid and semi arid regions of the world. Growers are facing increasing salinization of water and soils as well as reduced availability of water for irrigation. There are studies on the impacts of salinity and the impacts of drought on crop yields but very little information on the combined effects of both stresses. We conducted an outdoor study with spinach a relatively salt tolerant high value crop, with treatments grown under various levels of salinity, two levels of water stress (drought) and treatments with the interaction of drought and salinity stress. We evaluated three replicates per treatment for yield, vegetative parameters, ion composition, and physiological parameters. The results show that under water stress the relative salt tolerance of spinach is increased, and under salt stress the relative tolerance to water stress is also increased. We developed a predictive response model that relates spinach yield to both water and salt stress individually and to the interaction of these stresses. This research is of interest to producers, plant response modelers and extension specialists who utilize irrigation in arid regions.

Technical Abstract: Critical shortages of fresh water throughout arid regions means that growers must face the choice of applying insufficient fresh water, applying saline water, or consider the option of combined water and salt stress. The best approach to manage drought and salinity is evaluation of the impact of water stress and salt stress individually and then examine their interactions on plant production. To analyze salinity and water stress responses and their interaction together on spinach growth an experiment was conducted from April 1 to May 21, 2013, using 6 different irrigation waters at electrical conductivity (EC): 4, 7, 9, 12, 15 dS m-1. Soil moisture was recorded by sensors and stress treatments were designed with soil water matric pressure as treatment I1 (-200 to -300 kPa), treatment I2 (-400 to -500 kPa) and control (no water stress). We thus controlled soil matric potential rather than utilizing different water applications and assuming a linear relation between water use and yield. We evaluated three replicates per treatment for yield, vegetative parameters, ion composition, and physiological parameters. The results show that under water stress the relative salt tolerance is increased, and under salt stress the relative tolerance to water stress is also increased. The water and salt stress are not additive. We report a predictive model that relates spinach yield to both water and salt stress individually and to the interaction of these stresses.