Use of Combined Saline and Fresh Water for Cultivation of Sorghum and Sunflower in Sistan Region

In recent years, use of brakish water in agriculture, through either mixing fresh and saline water prior to irrigation or through an alternate use of saline and fresh water has become the focus of attention. The aim followed in this study was to investigate the effect of different levels of saline and non-saline water and as well the way of their being mixed on the sunflower and sorghum crops and also on the control and adjustment of salts within soil profile. To follow the aim, an experiment was performed within a randomized complete block design of six treatments and three replications for either of sorghum and sunflower crops (36 blocks in total) in the experiment al fields of Zabol University within 2012-2013. Treatments included control (100 % freshwater), treated with two-third salty, one-half salty, one-third salty, 90% salty, and finally 100% salty water. The investigated cropping indices were comprised of dry weight of stem, leaf and aerial organs of the plant, plant height, and leaf area index. The results indicated that, for both crops, one-third salt treatment had the second most acceptable performance in terms of agronomy measures and also the abundance of salt in the soils profile, as after control. However the difference between one-third and both one-half and two-third treatments for most attributes as for sunflower was not statistically (p≤0.05) significant. Also, for sorghum the average dry weight and leaf area index in one-third treatment was not significantly different from control. Moreover, one-third treatment for either plant has the second lowest EC in layers 0-20 and 20-40 cm (about 2.5 dS/m) and 0-60 cm (less than 2 dS/m), after control. According to the results, it seems that the proposed method of salt and fresh water mixing in any way, highly decreases salt stress on plant, and diminishes salt accumulation in the soil profile.