EFFECTS SOIL COVERING AND CONTROLLED WATER TABLE ON DATE PALM GROWTH AND THE ROOT ZONE SALT BALANCE IN SOUTHWEST OF IRAN

摘要

Drought, shallow saline water table and subsequent salinisation are the major problems in aridrnand semi arid in Iran. The establishment period of date palm plant is highly sensitive to thesernproblems and need special management program. Lysimeter experiments were conductedrnto evaluate the influences of shallow saline water table on the salt balance of root zone andrndate palm growth. These experiments were carried out in three replicated split–plot designrnincluding 3 levels groundwater salinity (main plot; S1= <4, S2= 8 and S3=12 dS/m); two levelsrnsoil surface cover (sub plot: M1= no mulch and M2= date palm leaves mulch) and two waterrntable depths (D1=60 and D2=90 cm). The results showed that mulching help to increase saltrnleaching and decreased soil EC with water table at 60 cm depth. The maximum decrease wasrn2.55 dS/m in treatment D1S1M2. The EC of root zone soil increased in treatments withoutrnmulch, the maximum being 6.31 dS/m in treatment D1S3M1. The soil EC increased in allrntreatments with controlled water table at 90 cm depth. The maximum and minimum changernof soil EC was 6.5 and 2.64 dS/m in treatments D2S3M1 and D1S1M2, respectively. ThernANOVA analyses indicated that mulch has a significant effect on salt change rate of the rootrnzone at 1% level. However, levels of salinity did not have a significant difference. Similar resultsrnwere obtained for both depths of the water table. The survival rate of plants was 100% in allrnof treatments. The date palm plants tolerated soil salinity till 14.29 dS/m. Mulch improvedrnthe growth of date palm plant. With controlled water table at 60 cm, the new leaf and leafletrnnumbers were 4.33 and 117.67 in treatment D1S3M2. These indexes were 4 and 120.33 for.