Effect of Different Irrigation Systems on Root Distribution of Mature Olive trees in Gravel soils

The recommended strategies in intensifying water shortage condition is changing the surface irrigation system to drip irrigation، in which case notification of the root system of mature trees for drip irrigation management is essential. The goal of this study was to investigate the effects of surface irrigation، automatic drip irrigation and traditional drip irrigation on olive tree root growth. The soil texture was sandy loam with 50% gravel. The fresh weight، dry weight and fresh volume of root were measured within 30 cm of tree under tree shadow area for 80 cm soil depth. The results showed that percent of fresh weigh was reduced 40% to 5% and 5 to 4 gr with increasing of depth and tree trunk distance to 240 cm، respectively. Also existence of gravel in soil was effective in root development، and fresh weigh and fresh volume density were decreased with increased of gravel. The olive root development was affected by irrigation system and dripper layout. The results showed that، changing of surface irrigation system to drip irrigation system for mature olive trees is possible; however، need to consider root growth system under previous irrigation system.