Determination of Salinity and Water Sensitivity Coefficient with the approach study water productivity of Kochia Scoparia L. in Ahvaz Climate

The problem of salinity of water resources and lack of quality water resources is one of the main threats to agricultural development in arid and semi-arid areas such as Khuzestan. Regarding existing problems, low irrigation method, using high salinity drainage, planting salinity resistant plants, and increasing water productivity are good management options. So, a study was conducted to determine the water sensitivity coefficient, salinity stress and Kochia water productivity in salinity and low water stress conditions in Ahvaz. The present study was carried out on Kochia plant at four salinity levels including Karoon river water (as the control with EC equal to 2.5 dS/m), 10, 15, 20 (dS/m) (S1, S2, S3 and S4, respectively) as the main factor and three levels of water deficit including 100, 75 and 50% water demand (I1, I2 and I3 respectively) as the sub plots in three replications (R1, R2 and R3) and as lysimetric in split plot and complete block designs. According to the results, the salinity stress coefficient in this study was between 0.06 and 0.89. The results showed that the coefficient of salinity decreased (Ks) by increasing water salinity. Also, the results showed that the Ks coefficients obtained in combination of salinity stress and 50% water deficit were higher than 75% water deficit stress. The average of Ky coefficient obtained in this study in under deficit irrigation conditions of 75% and 50% of water requirement was 0.19 and 0.60, respectively, indicating that Kochia has a low drought coefficient, which indicates high tolerance of this plant is not affected by severe drought stress conditions. The results also showed that the water productivity in the forage production of the Kochia plant is acceptable and high even under severe stress conditions, combined with salinity and water deficit. In this research, it was observed that salinity reduced water productivity and water utilization in deficit irrigation conditions was more than full irrigation. In general, the results of this study showed that kochia can be used as an appropriate forage plant in areas such as Ahvaz, where irrigation water and soil are not of desirable quality even without the need for leaching and soil remediation, which would cost a lot to producers.