Effect of Irrigation Water Salinity on Soil Moisture and Salinity during Growing Season, Barley Yield, and Its Water Productivity

In a 2-year field study, soil moisture and EC of soil extract (ECe) during growing season as well as grain and biological yield and water productivity of barley plant cv. Nosrat were monitored as affected by two salinity levels of irrigation water. Salinity levels of irrigation water were 2 and 12 dS.m-1. The results showed that salinity stress reduced grain, biological yield, and water productivity by, respectively, 36.0%, 52.1%, and 23.0% in the first year, and 48.4%, 69.1% and 31.7% in the second year. Higher losses in the second year were due to lower precipitation. Two-year averages of water productivity in terms of grain yields were 0.87 and 0.64 kg/m3, for 2 and 12 dS.m-1 water, respectively. In all days after imposing salinity treatment, soil moisture in control plots was significantly lower than saline plots. This difference was more distinct in the first depth and continued until the end of the growing season. On average, soil moisture levels in saline plots were higher than the control plots by 16.8% and 22.4% in the first and second years, respectively. In both years, ECe was also affected by salinity treatment, and this effect became more over time. The 2 and 12 dS m-1 salinity treatments decreased and increased ECe, respectively. The highest ECe values were observed at 160 days after planting in all three soil depths. Overall, in this condition, irrigation with saline water increased ECe about twice at the end of season compared to early growth, and increased ECe by 20% over EC of irrigation water. Greater soil moisture in saline conditions is not useful for crops because it is not easily available and has low quality, however, halophytes such as Panicum antidotale, Kochia spp., Salicornia spp. in rotation with barley might use this higher soil moisture and produce acceptable yield with less water.