Interspersed Salt Affected and Unaffected Dryland Soils of the Lower Rio Grande Valley: II. Occurrence of Salinity in Relation to Infiltration Rates and Profile Characteristics

Abstract

Thirteen variables including chemical and physical characteristics, topographical features, and water table depth measurements were statistically analyzed for differences between seven saline and adjacent nonsaline soil profiles of Lower Rio Grande Valley salt-affected dryland soils. Cumulative intake and final intake rate, electrical conductivity of soil saturation extract, exchangeable sodium percentage, clay percentage, relative elevation, sand percentage, soil surface slope, and cation-exchange capacity were the variables most consistently different between saline and nonsaline soils. Profile salinity and water intake were both significantly correlated with profile sand and clay content and with soil surface elevation, In addition water infiltration was a function of profile salinity. Consideration of the effects of clay content, ground surface elevation, and soil slope on the processes of runoff and infiltration lead to the conclusion that the observed salinity pattern is due to differential infiltration of rainfall which results in differences in leaching between saline and nonsaline areas