干旱区生态环境知识资源中心

The feasibility to obtain quality agricultural products, irrigated with saline water, makes it necessary to assess areas peripheral to the irrigated oasis in order to determine their suitability for cropping. The goal is to combine diverse methodologies for mapping and assessing ecologically homogeneous units in marginal lands of Mendoza, using plant communities as an indicator of these units. A pilot area was surveyed using LANDSAT/TM image processing, and vegetation, soil and water table were analysed. Assessed vegetation units and their respective salinity ranges (dS m(-1)), up to 50 cm depth, were: steppe of Heterostachys ritteriana, 91-83; shrubland of Allenrolfea vaginata with H. ritteriana, 83-48; open shrubland of A.vaginata con Prosopis strombulifera, 62-55; open steppe of Suaeda divaricata with Atriplex argentina, 52-83; shrubland of S. divaricata con Lycium tenuis-pinosum, 40-43; open woodland of Prosopis flexuosa, 37-26; dense shrubland of Prosopis alpataco, 7-6. The concentration of soluble salts exceeds the critical levels tolerated by cultivated plants. No water tables were detected within 15 m from the surface. It is considered that soils have good drainage conditions, so they can be recovered without high investment. This methodological approach showed good correspondence among plant communities, their spectral expression, and soil salinity and drainage conditions.