Effects of shallow saline water table management on the root zone salt balance and date palm growth in South-West Iran

The establishment period of date palm needs special irrigation and drainage management programmes in south and south-west, Iran. To achieve these programmes, lysimeter experiments were conducted. The statistical design was a split-plot arrangement of a randomised complete block design with three replicates that included three levels of ground water salinity (main plot : S-1 <4, S-2 =8 and S-3 = 12 dS/m) and two levels of soil surface cover.(sub-plot : M-1=no mulch and M-2=date palm leaves mulch). These experiments were also conducted for two water table depths (D-1=60 cm and D-2=90 cm). The results showed that mulching helped to increase salt leaching and decreased soil EC in presence of a water table at the depth of 60 cm. The highest amount of decrease was 2.55 dS/m in treatment with D1S1M2. The highest amount of increase in treatments without mulch was 6.31 dS/m in D1S3M1. The soil EC increased in all the treatments of the experiment with D-2 depth. The maximum and minimum changes in soil EC were 6.5 and 2.64 dS/m in D2S3M1 and D1S1M2, respectively. The ANOVA analyses indicated that mulch had a significant effect on the salt change rate of the root zone at a level of 1%. However, the levels of salinity did not have a significant difference. The survival rate of plants was 100% in all the treatments. The highest EC of soil was 14.29 dS/m in treatment with D2S3M1. Mulch improved the growth of date palm. In experiments with a controlled water table at 60 cm, most of new leaf and leaflet numbers were 4.33 and 117.67, respectively, in treatment with D1S3M2. These indices were 4 and 120.33 for a depth of 90 cm obtained from treatment with D2S2M2. Therefore, if shallow saline water tables could be managed and soil surface could be covered, date palm plantation establishments could thrive without harmful symptoms.