Sorghum [Soghum bicolor (L.) Moench.] growth, and soil moisture and salt content as affected by irrigation water salinity

Abstract

Information on the impact of salinity of irrigation water on  soil moisture and salt content is scant in the literature. Therefore, in the present study, growth of sorghum as well as soil moisture and salt content were investigated as affected by irrigation water salinity. In this experiment, the effect of three salinity levels of irrigation water, i.e., 2, 7 and 14 dS m-1 was monitored on sorghum growth, and changes in soil moisture and salinity of soil saturated extract during the growing season. Irrigation water salinity, depending on the intensity of stress, reduced forage yield, so that 7 and 14 dS m-1 salinity decreased the fresh weight by 11% and 45% and the dry weight by 17% and 62%, respectively, compared to those in non-saline conditions. At two soil depths (0-30 cm and 30-60 cm), the lowest moisture content was observed under non-saline conditions and the highest at 14 dS m-1. The salinity of soil saturated extract was also increased with increasing salinity of irrigation water. By applying salinities of 2 and 14 dS m-1, soil salinity decreased and increased by the end of the growing season, respectively. However, soil salinity  in 7 dS m-1 treatment was decreased first and then increased until the end of the growing season. At the end of the growing season, the average soil salinity in 7 and 14 dS m-1 treatments was 1.8 and 1.4 times, respectively, higher than that of the irrigation water salinity. In a nutshell, in saline conditions, more moisture remains in the soil, which may help sustain the of growth of halophytes to some extent.