Effect of Water Salinity on Survival and Growth of Landscape Trees in Saudi Arabia

Abstract

A 20-week-long greenhouse experiment was carried out to determine the effect of water salinity on the survival and growth of landscape trees and soil properties. The survival period of trees decreased significantly with an increase in soil salinity resulting from irrigation water salinity. The survival period of Acacia nilotica and Prosopis juliflora was significantly more than Eucalyptus camaldulensis and Parkinsonia aculeate under different water salinity levels and soil types. The total biomass decreased significantly with an increase in soil salinity. Soil salinity and sodicity increased significantly with increasing irrigation water salinity and sodicity. P. juliflora tolerated soil salinity (ECe) up to 39.5 dS m−1 and A. nilotica up to 44.9 (ECe) when irrigated with water salinity of 12.80 dS m−1; P. aculeate up to 29.26 (ECe) when irrigated with water salinity of 6.45 dS m−1; and E. camaldulensisup to 34.3 (ECe) when irrigated with water salinity of 6.45 dS m−1. Tree survival and proper establishment is possible provided management practices such as leaching requirement (at least 15%), proper selection of trees, right irrigation water salinity, and proper planting methods are followed. The salt accumulation was significantly more in light than in heavy soil. A strong correlation (r2) was observed between soil salinity and plant biomass which indicated a significant decrease in biomass with an increasing soil salinity resulting from saline irrigation. The experiment proved the sequence in salt tolerance for different landscape trees as P. juliflora and A. nilotica > P. aculeate > E. camalduensis. The research findings suggest that A. nilotica and P. juliflora should be cultivated as landscape trees for controlling desertification, for establishing shelterbelts around oil refineries, and in sand stabilization projects under arid environmental conditions.