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

摘要

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: S₁ <4, S₂=8 and S₃=12 dS/m) and two levels of soil surface cover (sub-plot: M₁=no mulch and M₂=date palm leaves mulch). These experiments were also conducted for two water table depths (D₁=60 cm and D₂=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 D₂ 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.