Ecohydrology of productive systems: restoration of saline environments in the western Argentina

LANA, BELÉN NERINA; ALVAREZ, JUAN AGUSTÍN; MEGLIOLI, PABLO ANDRÉS; GUIDA-JHONSON, BÁRBARA; VILLAGRA, PABLO EUGENIO; CONY, MARIANO ANIBAL

San Luis

Workshop; I Regional Workshop on Isotope Ecohydrology; 2020

Grupo de Estudios Ambientales, IMASL (CONICET ? UNSL)

The accumulation of soluble salts in soils is one of the main environmental factors that contribute to the loss of the productive capacity of Argentina´s arid ecosystems. Only 5% of the total productive area in Argentina corresponds to irrigated areas (2.1 million ha), and it is estimated that 24% of this area is affected by salinization or sodicity processes (Sanchez and Guerra, 2017). In the Monte region, the irrigates lands affected by secondary salinization ascends to 25%. Forestation with native trees has emerged as an alternative for the environmental and productive recovery of these areas. The challenge to recover and improve the productivity of such degraded areas is complex because it should consider not only the specie salt-tolerance but also the soil and water physicochemical properties that condition the specie survival. The objective was to evaluate the salinity tolerance of native trees (Prosopis flexuosa and P. chilensis) to different salinity conditions in order to identify the main variable(s) affecting the survival of the species. Two native species were selected from different provenance of Monte region. Four plots with different salinity conditions (low, medium, high, and very high) were forested in a salinized irrigated area from Media Agua, Argentina . Soil and water that affect the spatial heterogeneity of soil salinity were evaluated and integrated with statistical analysis. The tolerance of each specie is relatively independent of the origin. P. flexuosa appears to be less affected by salinity than P. chilensis. The establishment is a critical stage for restoration of salinized areas. P. flexuosa from Fiambalá shows advantages during this period. High spatial heterogeneity of salinity was found within plots, mainly in the topsoil. The EC decreases with increasing soil depth. The phreatic level is relatively shallow so, if the species can access this water reservoir, chances of survival may increase. However the phreatic quality is variable spatially and temporally. Data suggest tolerance to salinity in both species. However P. flexuosa shows some advantages in establishment and higher tolerated salt concentration than P. chilensis. The concentration of salt and its spatial heterogeneity in the soil is a determining factor in the potential for restoration.