Factors Affecting Aggregate Stability and Water Dispersible Clay of Recently Cultivated Semiarid Soils of Argentina

Abstract

The aggregate stability and water dispersible clay of 18 surface soils ranging from 0 to 32 years of soybean monoculture after clearance from a farm of approximately 5000 ha in the semiarid Chacopampeana plain (Argentina) was studied. Both stability variables were correlated with soil properties influencing aggregate stability. Aggregate stability and water dispersible clay were correlated with the length of agricultural use, organic carbon (OC) content, cation exchange capacity, free Al oxides and hydroxides to clay ratio, exchangeable Ca2+ content and exchangeable Na+ percentage. A synergistic effect was observed between OC and free Al oxides and hydroxides. Clay content and electrolyte concentration of the saturation extract had no effect on aggregate stability and on water dispersible clay. From the results of this study it was concluded that the changing factors along agricultural use that affect water aggregate stability and water dispersible clay were exchange able Ca2+ content and OC content.