Effect of Sand-Filled Tunnels on Seedling Establishment of Some Tree Species on Saline Sodic Soils

Abstract

The study aimed to improve the soil water around seedlings in the irrigated farms south of Jebel Auilia town which is an area that is dry, devoid of trees and with saline and sodic soil. The main objective was to increase water percolation into the subsoil using tunnel filled with sand around seedling to increase lateral water movement. Seedlings from selected five tree species known for their tolerance to drought and salinity were used. The species were Acacia ampliceps, Casuarina equisetifola, Eucalyptus camaldulensis Grewia tenax, and Ziziphus spina-christi. The seedlings were raised in a nursery and transplanted in into irrigation ditches in a farm south of Jebel Auilia. Circular holes about 20 cm from the seedlings were made. They were one meter in depth. The holes were then filled with sandy soil and then covered with mesh. The treatment consisted of zero; one or two sand filled tunnels 20 cm away from each seedling. The seedlings were irrigated weekly. Seedling shoot length, diameter, number of branches and survival were evaluated periodically for 315 days. Generally, the treatment of the tunnels filled with sand didn’t increase the shoot length, diameter or the number of branches for the five tested species. The five tested species showed no significant differences under the three levels of the treatment. However, the shoot length, diameter and number of branches showed continued increase during the test period. Also, the rate of survival was high between 83% and 100% under treatments in the five tested species. These results may indicate that the sand tunnels didn’t improve the lateral water movement due to soil sodicity or there was sufficient xi downward movement of water that satisfied the seedlings requirement of moisture of these drought tolerant species. The study recommends use of drought tolerant species in Jebel Aulia area and further studies that monitor lateral water movement.