Land-use and topography shape soil and groundwater salinity in central Argentina

• Published in: Agricultural water management 2013-11, Vol.129, p.120-129
• Main Authors: Nosetto, M.D., Acosta, A.M., Jayawickreme, D.H., Ballesteros, S.I., Jackson, R.B., Jobbágy, E.G.
• Format: Article
• Language: English
• Subjects: absorption; Afforestation; Agricultural and forest climatology and meteorology. Irrigation. Drainage; Agronomy. Soil science and plant productions; Animal, plant and microbial ecology; Applied ecology; Biodrainage; Biological and medical sciences; climate; crops; Earth sciences; Earth, ocean, space; Ecohydrology; Environment and sustainable development; Eucalyptus; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; grasslands; groundwater; Hydrology. Hydrogeology; image analysis; land use; Pampas; plantations; roots; salinity; Salinization; salts; soil salinity; solutes; topography; trees; Water resources
• ISSN: 0378-3774; 1873-2283
• DOI: 10.1016/j.agwat.2013.07.017

•Topography and land-use strongly affected salinization patterns.•Land-use had a stronger influence than topography on salinity patterns.•Tree plantations stored >7 times more salts in soils than croplands and grasslands.•Resistivity imaging allowed a cost-effective description of salinity patterns and mechanisms. Being one of the oldest and most serious environmental problems, soil and groundwater salinization poses critical challenges for the managing of agricultural and natural areas. Together with climate, topography and land-use are main controls dictating salt accumulation patterns at different spatial scales. In this paper, we quantified the response of salt accumulation to the interactive effects of topography (lowland-upland gradients) and vegetation (annual crops, tree plantations, native grasslands) across a sub-humid sedimentary landscape with shallow groundwater in the Inland Pampas of Argentina. We measured salt stocks from the surface down to the water-table through soil coring and their horizontal distribution through electrical-resistivity imaging in eleven fields occupied by annual crops, eucalyptus plantations and grasslands, encompassing water-table depth gradients of 1–6m below the surface. Land-use and topography exerted strong influences on salinity and explained together 82% and 66% of the spatial variability of groundwater salinity and soil salt accumulation (0–2m of depth), respectively. As a single explanatory variable, land-use overwhelmed topography dictating salinity patterns. Tree plantations stored 7–8 times more salts than croplands and grasslands throughout the unsaturated soil profile in areas with shallow water-tables (