ABSTRACT

 Two soils of different textures, sandy loam (SL) (Soil A) from Umudike and sandy clay loam(SCL)(Soil B) from Owerri were used to study the effect of wetting and drying cycles on soil aggregate stability. Each of the two soils was subjected to six wetting and drying cycles — C1 , C3, C5, C10, C15, C20 and two controls, continuously dry(CD) and continuously wet(CD) . Aggregate stability and organic matter were measured at the end of each cycle. Data generated were subjected to a 2x8 factorial analysis. Also a correlation of organic matter with MWD was performed. Results showed that the treatments affected MWD of water stable aggregates. Relative to the controls, least aggregation occurred at the fifth cycle of wetting and drying in both soils while aggregation was highest at cycle one. Disaggregation was more pronounced in soil B which contained more clay. Wetting and drying cycles also affected organic matter content, though no regular pattern was observed. These soils under tropical conditions loose their stability especially when their organic matter contents are reduced.