Restoring salinized environments in irrigated arid lands from the Western Argentina: salt tolerance thresholds in Prosopis species.

VILLAGRA, P.E.,; LANA, N.B.; MEGLIOLI, P.; ALVAREZ, J.A.; CONY, M.

Congreso; 8th world conference on ecological restoration; 2019

The irrigated oases of Cuyo present large extensions with low aptitude for traditional crops due to the salinization caused by the bad management of the irrigation or the ascent of the phreatic layer. Forestation with native species such as Prosopis flexuosa and P. chilensis has emerged as an alternative for the environment and productive recovery of these areas. These species could be resistant to stressful conditions and promising for their multiple uses (posts, firewood and wood) and environmental benefits. In order to select suitable genetic material for restoration, the salinity tolerance of different origins of these two species was evaluated. Sixteen plots were experimentally forested in a salinity gradient of the salinized irrigated oasis from Media Agua (31°52' S - 68°23' W, San Juan, Argentina ). In each plot we measured the survival and growth of three origins of each species. In addition, we analyzed the spatial heterogeneity of soil salinity within each plot and we correlated it with spatial variability in survival and growth. A significant and negative correlation between soil electrical conductivity and survival and growth was observed. Survival was higher than 50% up to 40000 µS/cm. Differential growth and mortality within the plot were observed as a response to heterogeneity in soil salinity, with thresholds similar to those of the previous point. The data suggest tolerance of both species up to salinity levels higher than those of seawater. This tolerance is relatively independent of the origin, maintaining the differences in growth observed in the absence of salinity. The spatial heterogeneity of the soil is a determinant of the restoration potential.