Land use Influence on Vadose Water and Salt Fluxes: A Geoelectrical Perspective From Central Argentina

JAYAWICKREME, D; SANTONI, C; NOSETTO, M D; KIM, J H; JOBBÁGY, E G; JACKSON, R

Toronto, Canada

Congreso; American Geophysical Union. Joint Assembly; 2009

Native dry forests continue to be replaced by rain-fed annual crops in the semi arid plains of central Argentina. The resulting changes in vegetation cover alter the partitioning of precipitation affecting recharge rates and solute transport in the vadose zone. Like similar dry forests from other continents, these deep rooted native ecosystems have virtually no drainage below the rooting zone. Their replacement by annual crops can lead to the onset of deep drainage, solute displacements, and rising water tables that could affect the long-term viability of agriculture in the region. To understand the ecohydrological implications of this vegetation change we evaluate deep subsurface water and solute distributions using soil coring and electrical resistivity imaging along a chronosequence of agricultural plots that where converted from forests 1 to 90 years ago. Our findings suggest a progressive increase of soil moisture and leaching of salts in the vadose zone following the onset of cultivation