Lysimeter water and salt balance study of the roots of palm trees under different field managements

Salinity and drought are the major problems in arid and semi arid areas. To evaluate the effect of water table control on the root zone salt balance and plant growth, lysimeter experiments were conducted. The statistical design was a split–plot-plot arrangement of randomized complete block design with three replicates that included 3 levels of ground water salinity (main plot; S1= <4, S2= 8 and S3=12 dS/m), 2 water table depths (sub plot: D1=60 and D2=90 cm) and two levels of soil surface cover (sub plot plot: M1= no mulch and M2= date palm leaves mulch). In these experiments, sufficient leaching was not provided. The results showed that shallow water table increased accumulated ETc 4.43-9.23 % in treatments without mulch and 9.28-12.23 in mulched treatment. Also mulching and water table control helps to increase salt leaching and decrease soil EC. The survival rate of plants was 100% in all the treatments. Also mulch improved the growth of date palm. The ANOVA analyses indicated that mulch had a significant effect on water balance and salt change rate of the root zone, new leaf and leaflet numbers at level of 1%. However, the levels of salinity did not have a significant difference.